Author name code: sheeley
ADS astronomy entries on 2022-09-14
author:"Sheeley, Neil R." 
------------------------------------------------------------------------  

Title: The Sun's Mean Line-of-Sight Field
Authors: Sheeley, Neil R., Jr
Bibcode: 2022arXiv220803216S
Altcode:
  We regard the Sun-as-a-star magnetic field (i.e. the mean field) as
  a filter for the spherical harmonic components of the photospheric
  field, and calculate the transmission coefficients of this filter. The
  coefficients for each harmonic, $Y_{l}^{m}$, are listed in three tables
  according to their dependence on $B_{0}$, the observer's latitude in
  the star's polar coordinate system. These coefficients are used to
  interpret the 46-yr sequence of daily mean-field measurements at the
  Wilcox Solar Observatory. We find that the non-axisymmetric part of the
  field originates in the $Y_{1}^{1}$, $Y_{2}^{2}$, and a combination of
  the $Y_{3}^{3}$ and $Y_{3}^{1}$ harmonic components. The axisymmetric
  part of the field originates in $Y_{2}^{0}$ plus a $B_{0}$-dependent
  combination of the $Y_{1}^{0}$ and $Y_{3}^{0}$ components. The
  power spectrum of the field has peaks at frequencies corresponding
  to the ~27-day synodic equatorial rotation period and its second
  and third harmonics. Each of these peaks has fine structure on its
  low-frequency side, indicating magnetic patterns that rotate slowly
  under the influence of differential rotation and meridional flow. The
  sidebands of the fundamental mode resolve into peaks corresponding
  to periods of ~28.5 and ~30 days, which tend to occur at the start
  of sunspot maximum, whereas the ~27-day period tends to occur toward
  the end of sunspot maximum. We expect similar rotational sidebands
  to occur in magnetic observations of other Sun-like stars and to be
  a useful complement to asteroseismology studies of convection and
  magnetic fields in those stars.

Title: Acceleration of Coronal Mass Ejection Plasma in the Low Corona
    as Measured by the Citizen CATE Experiment
Authors: Penn, Matthew J.; Baer, Robert; Walter, Donald; Pierce,
   Michael; Gelderman, Richard; Ursache, Andrei; Elmore, David; Mitchell,
   Adrianna; Kovac, Sarah; Hare, Honor; McKay, Myles; Jensen, Logan;
   Watson, Zachary; Conley, Mike; Powers, Lynn; Lazarova, Marianna;
   Wright, Joseph; Young, David; Isberner, Fred; Hart, C. Alexandra;
   Sheeley, N. R., Jr.; Penn, Debbie; Allen-Penn, Kate; Alder, Bruce;
   Alder, Ryan; Hall-Conley, Geri; Gerdes, David; Weber, Katherine;
   Johnson, Jeffrey; Matzek, Gerald; Somes, Steven; Sobnosky, Rob;
   McGowen, Robert; Meo, Michael; Proctor, Damani; Wessinger, Charlie;
   Schilling, Jeannine; Kerr, Jay; Beltzer-Sweeney, Alexander; Falatoun,
   Alex; Higgins, David; Boyce, Grady; Hettick, Jared; Blanco, Philip;
   Dixon, Scott; Ardebilianfard, Sepehr; Boyce, Pat; Lighthill, Richard;
   Lighthill, Denese; Anderson, David; Anderson, Mine; Schad, Thomas;
   Smith, Sonna; Jensen, Declan; Allen, Anthony; Smith, Donavan; Brandon,
   Gage; Earp, Joe; Earp, Jane; Blair, Bob; Claver, Chuck F.; Claver,
   Jennifer A.; Claver, Ryan H.; Hoops, Danielle; Rivera, Esteban;
   Gibson, Llanee; Hiner, Martin; Lann, Rein; Miller, Shaedyn; Briggs,
   Burton; Davis, Karan; Jackson, Brian; Kautzsch, Kaleb; Sandidge,
   Wesley; Lucas, Russell; Gregg, Duane; Kamenetzky, Julia; Rivera,
   Tiffany; Shaw, Joe; Scherrer, Bryan; Sandbak, Dylan; McFate, Richard;
   Harris, Wilson; Brasier, Zachery; McNeil, Stephen; Jensen, Jack;
   Jensen, Makai; Moore, Mason; Temple, Alexandria; Vanderhorst, Thomas;
   Kautz, Richard; Bellorado, Orion; Jenkins, LaVor R.; Pantuso, Corey;
   Carey, Marley; Byrnes, Josh; Scholtens, Kyle; Web, Julian; Baker,
   Brain; Barngrover, Katie; Hathaway, Drew; Smith, Kallen; Chandler,
   Kellyn; Hinkle, Lydia; Chandler, Ione; Gisler, Galen; Benner, Jack;
   Mas, Madison; Rogers, Maya; Moore, Prescott; Pelofske, Elijah;
   Gulley, Stephen; Short, Beth; Crooker, Isabel; Hammock, Jennifer;
   Cardenas, Katsina; Cardenas, Kateri; Wellman, Jennifer; Roy, Mark;
   Meyer, Joe; Brough, Jalynne; Brough, Kameron; Nelson, Tim; Nelson,
   Zack; Russell, Caleb; Bautz, Theresa; Weitzel, Eric; Team; Wistisen,
   Michele; Aagard, Shae; Whipps, Zachary; Neuroth, Logan; Poste, Dawson;
   Worthen, Connor; Gosain, Sanjay; Steward, Mark; Gosain, Vanshita;
   Gosain, Ruchi; Jorgensen, Janet; Doucette, Eleanor; Doucette, Reba;
   Iwen, Elliott; Cochran, Alexus; Stith, James; Scribner, Doug; Kenney,
   Austen; Pisciotti, Kolby; Pease, Irene; Cynamon, Samuel; Cynamon,
   Charles; Cynamon, Dawn; Tolbert, Bart; Dupree, Jean A.; Weremeichik,
   Jeremy; Pindell, Nathan; Stives, Kristen; Simacek, Thomas K.; Simacek,
   Yolanta G.; Simacek, Anne L.; Boeck, Wayne; Boeck, Andreea; Ryan,
   Austin; Wierzorec, Gabriel; Klebe, Dimitri; Costanza, Bryan; Cerny,
   Arnie; Schmale, Trevor; Hoffman, Tessa; Streeter, Sam; Erickson,
   Jack; McClellan, Michele; Erickson, Ella; Brettell, Brynn; Shoffner,
   Savannah; McClellan, Emilie; VanVoorhis, Julie; Bramhall, Cole; Stelly,
   Daniel; Bee, Bentley; Acevedo, Bruno; Kroeger, Madison; Trumpenski,
   Ben; Sump, Nolan; Brook, Liam; Ernzen, Jagert; Lewis, Jessica;
   Maderak, Ryan; Kennedy, Charles; Dembinski, David; Wright, Rita;
   Foster, Michael; Ahmadbasir, Mohammad; Laycox, Monty; Foster, James;
   Orr, Ethan; Staab, Ashley; Speck, Angela; Baldridge, Sean; Kegley,
   Lucy; Bavlnka, Jordan; Ballew, Thomas; Callen, Bruce; Ojakangas,
   Gregory; Bremer, Mark; Angliongto, Maryanne; Redecker, Mark; Bremer,
   Chris; Hill, Peggy; Rodgers, Michael; Duncan, Jordan; Fincher, Sam;
   Nielsen, Ben; Hasler, Samantha; Shivelbine, Taylor; Howard, Tyler;
   Midden, Chris; Patrick, Sean; Glenn, Kerry; Mandrell, Chris; Dawson,
   Kyle; Cortez, Margaret; Levsky, Alyssa; Gallaba, Dinuka; Perrone,
   Mason; Taylor, Jasmyn; Yanamandra-Fisher, Padma A.; Harper, Howard;
   Adams, Lindsay; Springer, Michaela; Menard, BillyJoe; Boggs, Dylan;
   Lynch, Caitlin; Watson, Jacob; York, Andi; Matthews, David; Brown,
   Kiley; Garrison, Dylan; Mangin, Jonathan; Mangin, Isaac; Birriel,
   Jennifer; Birriel, Ignacio; Yess, Capp; Anderson, Jesse; Caudill,
   Ethan; Smith, Allyn; Buckner, Spencer; Longhurst, Russ; Fagan, Ben;
   Nations, Christian; DiMatties, Jeffrey; Thompson, Patricia; Garrison,
   David; Garrison, Thomas; Garrison, William; Kidd, Mary; Baker, Maria;
   Ledford, Mary-Beth; Winebarger, Amy; Freed, Michael; Church, Morgyn;
   Dickens, Jim; Anderson, Bob; Smith, Ned; Dorsey, Lynne; Justice, Doug;
   Zavala, Daniel; Stockbridge, Zach; Brittain, Sean; Jensen, Stanley;
   Leiendecker, Harrison; Thompson, Erin; Deady, Michelle; Quinn-Hughes,
   Kelly; Slimmer, David; Granger, Valerie; LaRoche, Michael; Hill
   LaRoche, Serena; Manspeaker, Rachel; Nguyen, Peter; Smith, Daniel;
   Payne, Jim; Zissett, Jerry; Roberts, Arianna M.; Roberts, Gabrielle
   W.; Roberts, Harrison; Riddle, Amy; Ursache, Corina; Ursache, Elena
Bibcode: 2020PASP..132a4201P
Altcode:
  The citizen Continental-America Telescopic Eclipse (CATE) Experiment
  was a new type of citizen science experiment designed to capture a time
  sequence of white-light coronal observations during totality from 17:16
  to 18:48 UT on 2017 August 21. Using identical instruments the CATE
  group imaged the inner corona from 1 to 2.1 RSun with 1.″43 pixels
  at a cadence of 2.1 s. A slow coronal mass ejection (CME) started on
  the SW limb of the Sun before the total eclipse began. An analysis
  of CATE data from 17:22 to 17:39 UT maps the spatial distribution of
  coronal flow velocities from about 1.2 to 2.1 RSun, and shows the CME
  material accelerates from about 0 to 200 km s<SUP>-1</SUP> across this
  part of the corona. This CME is observed by LASCO C2 at 3.1-13 RSun
  with a constant speed of 254 km s<SUP>-1</SUP>. The CATE and LASCO
  observations are not fit by either constant acceleration nor spatially
  uniform velocity change, and so the CME acceleration mechanism must
  produce variable acceleration in this region of the corona.

Title: Memorable Events During a Research Career
Authors: Sheeley, Neil R.
Bibcode: 2019JGRA..124.4949S
Altcode:
  In this paper, I sketch a path through my research career in solar and
  heliospheric physics, recalling some memorable events and discoveries
  that occurred along the way. This chain of events begins with an
  influential Time magazine article in 1955 and progresses through a
  summer at Bell Labs, 9 years at Caltech, 7 years at the Kitt Peak
  National Observatory, 43 years at the Naval Research Laboratory, and
  ends with a digitized map of the Sun's Ca II K-Line emission in 1919
  when the AGU was born. Accidents and puzzling results are often the
  keys to progress and should be examined carefully.

Title: Observational Evidence for the Associated Formation of Blobs
    and Raining Inflows in the Solar Corona
Authors: Sanchez-Diaz, Eduardo; Rouillard, Alexis P.; Davies, Jackie
   A.; Lavraud, Benoit; Sheeley, Neil R.; Pinto, Rui F.; Kilpua, Emilia;
   Plotnikov, Illya; Genot, Vincent
Bibcode: 2017EGUGA..19.4855S
Altcode:
  The origin of the Slow Solar Wind (SSW) is still a topic of much
  debate. The continual emergence of small transient structures from
  helmet streamers is thought to constitute an important sources of the
  SSW. Determining the height at which these transients are released
  is an important factor in determining the conditions under which the
  SSW forms. To this end, we have carried out a multipoint analysis of
  small transient structures released from a north-south tilted helmet
  streamer into the slow solar wind over a broad range of position
  angles during Carrington Rotation 2137. During this period of time,
  the catalogue in Sheeley &amp; Wang (2014) reported a big number of
  transient structures collapsing back toward the Sun, referred to as
  "raining inflows". Combining the remote-sensing observations taken
  by the Solar-TErrestrial RElations Observatory (STEREO) mission with
  coronagraphic observations from the SOlar and Heliospheric Observatory
  (SOHO) spacecraft, we show that the release of such small transient
  structures (often called blobs), which subsequently move away from
  the Sun, is associated with the concomitant formation of raining
  inflows. This is the first direct association between outflowing blobs
  and raining inflows, which locates the formation of blobs above the
  helmet streamers and gives strong support that the blobs are released
  by magnetic reconnection. This work was made with the funding from
  the HELCATS project under the FP7 EU contract number 606692

Title: Tracking the Magnetic Flux in and around Sunspots
Authors: Sheeley, N. R., Jr.; Stauffer, J. R.; Thomassie, J. C.;
   Warren, H. P.
Bibcode: 2017ApJ...836..144S
Altcode:
  We have developed a procedure for tracking sunspots observed by the
  Helioseismic and Magnetic Imager on the Solar Dynamics Observatory
  and for making curvature-corrected space/time maps of the associated
  line-of-sight magnetic field and continuum intensity. We apply
  this procedure to 36 sunspots, each observed continuously for nine
  days around its central meridian passage time, and find that the
  proper motions separate into two distinct components depending on
  their speeds. Fast (∼3-5 km s<SUP>-1</SUP>) motions, comparable
  to Evershed flows, are produced by weak vertical fluctuations of the
  horizontal canopy field and recur on a timescale of 12-20 min. Slow
  (∼0.3-0.5 km s<SUP>-1</SUP>) motions diverge from a sunspot-centered
  ring whose location depends on the size of the sunspot, occurring in the
  mid-penumbra for large sunspots and at the outer edge of the penumbra
  for small sunspots. The slow ingoing features are contracting spokes of
  a quasi-vertical field of umbral polarity. These inflows disappear when
  the sunspot loses its penumbra, and may be related to inward-moving
  penumbral grain. The slow outgoing features may have either polarity
  depending on whether they originate from quasi-vertical fields of umbral
  polarity or from the outer edge of the canopy. When a sunspot decays,
  the penumbra and canopy disappear, and the moat becomes filled with
  slow outflows of umbral polarity. We apply our procedure to decaying
  sunspots, to long-lived sunspots, and to numerical simulations of a
  long-lived sunspot by Rempel.

Title: Observational Evidence for the Associated Formation of Blobs
    and Raining Inflows in the Solar Corona
Authors: Sanchez-Diaz, E.; Rouillard, A. P.; Davies, J. A.; Lavraud,
   B.; Sheeley, N. R.; Pinto, R. F.; Kilpua, E.; Plotnikov, I.; Genot, V.
Bibcode: 2017ApJ...835L...7S
Altcode: 2016arXiv161205487S
  The origin of the slow solar wind is still a topic of much debate. The
  continual emergence of small transient structures from helmet
  streamers is thought to constitute one of the main sources of the slow
  wind. Determining the height at which these transients are released
  is an important factor in determining the conditions under which the
  slow solar wind forms. To this end, we have carried out a multipoint
  analysis of small transient structures released from a north-south
  tilted helmet streamer into the slow solar wind over a broad range
  of position angles during Carrington Rotation 2137. Combining the
  remote-sensing observations taken by the Solar-TErrestrial RElations
  Observatory (STEREO) mission with coronagraphic observations from the
  SOlar and Heliospheric Observatory (SOHO) spacecraft, we show that
  the release of such small transient structures (often called blobs),
  which subsequently move away from the Sun, is associated with the
  concomitant formation of transient structures collapsing back toward
  the Sun; the latter have been referred to by previous authors as
  “raining inflows.” This is the first direct association between
  outflowing blobs and raining inflows, which locates the formation of
  blobs above the helmet streamers and gives strong support that the
  blobs are released by magnetic reconnection.

Title: The Stereo Electron Spikes and the Interplanetary Magnetic
    Field
Authors: Jokipii, J. R.; Sheeley, N. R., Jr.; Wang, Y. M.; Giacalone,
   J.
Bibcode: 2016AGUFMSH51G..06J
Altcode:
  A recent paper (Klassen etal, 2015) discussed observations of a spike
  event of 55-65 keV electrons which occurred very nearly simultaneously
  at STEREO A and STEREO B, which at the time were separated in longitude
  by 38 degrees. The authors associated the spikes with a flare at the
  Sun near the footpoint of the nominal Archimedean spiral magnetic
  field line passing through STEREO A. The spike at STEREO A was delayed
  by 2.2 minutes from that at STEREOB. We discuss the observations in
  terms of a model in which the electrons, accelerated at the flare,
  propagate without significant scattering along magnetic field lines
  which separate or diverge as a function of radial distance from the
  Sun. The near simultaneity of the spikes at the two spacecraft is a
  natural consequence of this model. We interpret the divergence of the
  magnetic field lines as a consequence of field-line random walk and
  flux-tube expansion. We show that the field-line random walk in the
  absence of flux-tube expansion produces an rms spread of field lines
  significantly less than that which is required to produce to observed
  divergence. We find that observations of the solar wind and its source
  region at the time of the event can account for the observations in
  terms of propagation along interplanetary magnetic field-lines. Klassen,
  A., Dresing, N., Gomez-Herrero, R, and Heber, B., A&amp;A 580, A115
  (2015) Financial support for NS and YMW was provided by NASA and CNR.

Title: Can collisions regulate the He++ abundance of the slow
    solar wind?
Authors: Sanchez Diaz, Eduardo; Blelly, A. P. Rouillard. L.; Pinto,
   R.; Lavraud, B.; Segura, K.; Tao, C.; Sheeley, N. R.; Plotnikov, I.
Bibcode: 2016shin.confE..80S
Altcode:
  At solar maximum, the slow solar wind presents an enhanced alpha
  abundance compared to solar minimum (Aellig et al., 2001; Kasper et al.,
  2007, 2012). Sanchez-Diaz et al. (2016) found that the yearly averages
  of alpha abundance in the slow solar wind is very well correlated
  with the yearly averages of the proton mass flux right above the
  transition region. This correlation is especially remarkable for the
  very slow solar wind (V&lt;300 km/s), where this proton flux is very
  high and variable (5 times bigger than at solar minimum and one order
  of magnitude bigger than in the fast solar wind). We hypothesized that
  the alpha abundance might be enhanced due to a non-negligible amount of
  Coulomb collisions between protons and alphas due to this high proton
  flux. To explore the role of H+ ? He++ collisions in the acceleration of
  He++ ions, we input the proton temperature and expansion factor profiles
  resulting from the combination of a Potential Field Source Model (PFSS)
  and a 1D hydrodynamic solar wind model described in Pinto et al. (2009)
  into a collisional two fluid hydrostatic model. The model assumes that
  there is no heating for the He++ ions in the very slow solar wind. We
  evaluate the possible role of Coulomb collisions on the escape of He++
  for different geometries and boundary conditions. We find that there
  is a region right above the transition region where the collisions
  have the effect of transferring momentum from the protons to the
  alphas. This is the region where the hydrogen may be accelerated by
  collisions with hydrogen. In the upper Corona it is the alphas that
  would transfer momentum to the protons and the collisions have the
  effect of slowing the alphas down. <P />This study was carried out as
  part of the HELCATS FP7 project

Title: Multipoint observation of coronal inflows
Authors: Sanchez Diaz, Eduardo; Rouillard, A.; Davies, J.; Lavraud,
   B.; Plotnikov, I.; Sheeley, N. R.; Pinto, R.
Bibcode: 2016shin.confE.112S
Altcode:
  Corotating Interaction Regions (CIRs) are filled with numerous
  small-scale transients. Outward moving blobs have been commonly
  observed in LASCO and SECCHI (Plotnikov et al. 2016; Rouillard et
  al., 2008, 2009, 2010; Sheeley et al., 1997). Inward moving blobs,
  or inflows, have been observed in LASCO C2 over the last two solar
  cycles (Wang et al., 1999a,b; Sheeley et al., 2001,2002,2007,2014). On
  rare occasions, inflows and outflows are observed together and in
  apparent association. Outward moving blobs and inflows are thought
  to be the products of the same process: magnetic reconnection at
  around 4-5 solar radii producing an inflow-outflow pair. However,
  only one isolated signature (either inflow or outflow) is reported
  in most observations. The second signature is thought to usually lie
  outside the field-of-view (FOV) of the instruments, or below their
  sensitivity limit. <P />Here we show observations of the same CIR by
  combining the SECCHI and LASCO instrument onboard STEREO and SOHO. The
  FOV of SECCHI-COR2 allows us to see the outflow part associated to
  the inflows. This outflow can be followed all the way out in the
  Heliosphere with SECHHI-HI1 and HI2. During May and June 2013, the
  magnetic field topology of the corona, with a nearly vertical neutral
  line, and the lack of CMEs was optimal to observe blobs and inflows at
  all latitudes. We present a 3D reconstruction of all the small-scale
  transients, both inflows and outflows, entrained by this CIR. This
  includes the first observation of inflows with COR2 and the first
  multipoint observation of the inflows entrained by the same CIR from
  two satellites. We evaluate the presumed connection between coronal
  inflows, in-out pairs and blobs and discuss the origin of blobs and
  their likely association to a continuous magnetic reconnection process
  in the Solar Corona. <P />This study was carried out as part of the
  HELCATS FP7 project

Title: The very slow solar wind: Properties, origin and variability
Authors: Sanchez-Diaz, Eduardo; Rouillard, Alexis P.; Lavraud,
   Benoit; Segura, Kevin; Tao, Chihiro; Pinto, Rui; Sheeley, N. R.;
   Plotnikov, Illya
Bibcode: 2016JGRA..121.2830S
Altcode:
  Solar wind slower than 300 km/s, hereafter termed very slow solar
  wind (VSSW), is seldom observed at 1 AU. It was, however, commonly
  measured inside 0.7 AU by the two Helios spacecraft, particularly
  during solar maximum. Magnetohydrodynamic (MHD) modeling reveals that
  the disappearance of VSSW at 1 AU is the result of its interaction
  with faster solar wind. The acceleration and compression of the VSSW
  contributes to the observed highly variable structure of the slow
  solar wind at 1 AU. The VSSW usually contains the heliospheric plasma
  sheet and current sheet. It has higher density and lower temperature
  than the regular slow solar wind, extending the known scaling laws
  below 300 km/s. Its helium abundance increases with solar activity
  even more significantly than the slow solar wind. Contrary to faster
  solar winds, the helium ions in the VSSW are slower than the dominant
  protons. Combining a Potential Field Source Surface (PFSS) model with
  ballistic back tracing, we study the source region of the VSSW. We
  show that the proton density flux for the VSSW is much higher than
  for the faster winds, particularly at solar maximum.

Title: Geographically Distributed Citizen Scientist Training for
    the 2017 Citizen CATE Experiment
Authors: Gelderman, Richard; Penn, Matt; Baer, Robert; Isberner,
   Fred; Pierce, Michael; Walter, Donald K.; Yanamandra-Fisher, Padma;
   Sheeley, Neil R.
Bibcode: 2016AAS...22734902G
Altcode:
  The solar eclipse of 21 August 2017 will be visible to over a half
  billion people across the entire North American continent. The roughly
  100-mile wide path of totality, stretching from Oregon to South
  Carolina, will be the destination for tens of millions of people. In
  the decades since 1979, when the last total solar eclipse was visible
  from the continental USA, the phenomenon of Internet enabled citizen
  science has grown to be an accepted mode for science. The Citizen
  Continental-America Telescopic Eclipse (Citizen CATE) experiment
  has been funded as one of the three 2017 eclipse related NASA STEM
  agreements to engage citizen scientists in a unique, cutting-edge
  solar physics experiment. Teams across the USA will be trained to use
  standardized refracting telescope and digital imager set-ups to observe
  the solar corona during the eclipse, acquiring multiple exposures to
  create one high dynamic range image. After observing during the eclipse,
  the CATE volunteers will upload the combined image to a cloud-storage
  site and the CATE team will then work to properly orient and align all
  the images collected from across the continent to produce a continuous
  90-minutes movie. A time-compressed first cut of the entire sequence
  will be made available to media outlets on the same afternoon of
  the eclipse, with hope that high quality images will encourage the
  most accurate coverage of this Great American Eclipse. We discuss
  overall the project, as well as details of the initial tests of the
  prototype set-up (including in the Faroe Islands during the March 2015
  total solar eclipse) and plans for the future night-time and day-time
  observing campaigns, and for a handful of observing teams positioned
  for overlapping observations of the March 2016 total solar eclipse in
  the South Pacific.

Title: Coronal Mass Ejections and the Solar Cycle Variation of the
    Sun's Open Flux
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 2015ApJ...809L..24W
Altcode: 2021arXiv210407238W
  The strength of the radial component of the interplanetary magnetic
  field (IMF), which is a measure of the Sun’s total open flux, is
  observed to vary by roughly a factor of two over the 11 year solar
  cycle. Several recent studies have proposed that the Sun’s open
  flux consists of a constant or “floor” component that dominates
  at sunspot minimum, and a time-varying component due to coronal mass
  ejections (CMEs). Here, we point out that CMEs cannot account for
  the large peaks in the IMF strength which occurred in 2003 and late
  2014, and which coincided with peaks in the Sun’s equatorial dipole
  moment. We also show that near-Earth interplanetary CMEs, as identified
  in the catalog of Richardson and Cane, contribute at most ∼30% of the
  average radial IMF strength even during sunspot maximum. We conclude
  that the long-term variation of the radial IMF strength is determined
  mainly by the Sun’s total dipole moment, with the quadrupole moment
  and CMEs providing an additional boost near sunspot maximum. Most of
  the open flux is rooted in coronal holes, whose solar cycle evolution
  in turn reflects that of the Sun’s lowest-order multipoles.

Title: The Recent Rejuvenation of the Sun's Large-scale Magnetic
Field: A Clue for Understanding Past and Future Sunspot Cycles
Authors: Sheeley, N. R., Jr.; Wang, Y. -M.
Bibcode: 2015ApJ...809..113S
Altcode:
  The quiet nature of sunspot cycle 24 was disrupted during the second
  half of 2014 when the Sun’s large-scale field underwent a sudden
  rejuvenation: the solar mean field reached its highest value since
  1991, the interplanetary field strength doubled, and galactic cosmic
  rays showed their strongest 27-day modulation since neutron-monitor
  observations began in 1957; in the outer corona, the large increase of
  field strength was reflected by unprecedentedly large numbers of coronal
  loops collapsing inward along the heliospheric current sheet. Here, we
  show that this rejuvenation was not caused by a significant increase in
  the level of solar activity as measured by the smoothed sunspot number
  and CME rate, but instead was caused by the systematic emergence of flux
  in active regions whose longitudinal distribution greatly increased the
  Sun’s dipole moment. A similar post-maximum increase in the dipole
  moment occurred during each of the previous three sunspot cycles,
  and marked the start of the declining phase of each cycle. We note
  that the north-south component of this peak dipole moment provides
  an early indicator of the amplitude of the next cycle, and conclude
  that the amplitude of cycle 25 may be comparable to that of cycle 24,
  and well above the amplitudes obtained during the Maunder Minimum.

Title: Using Running Difference Images to Track Proper Motions of
    XUV Coronal Intensity on the Sun
Authors: Sheeley, N. R., Jr.; Warren, H. P.; Lee, J.; Chung, S.;
   Katz, J.; Namkung, M.
Bibcode: 2014ApJ...797..131S
Altcode:
  We have developed a procedure for observing and tracking proper
  motions of faint XUV coronal intensity on the Sun and have applied
  this procedure to study the collective motions of cellular plumes and
  the shorter-period waves in sunspots. Our space/time maps of cellular
  plumes show a series of tracks with the same 5-8 minute repetition
  times and ~100 km s<SUP>-1</SUP> sky-plane speeds found previously
  in active-region fans and in coronal hole plumes. By synchronizing
  movies and space/time maps, we find that the tracks are produced by
  elongated ejections from the unipolar flux concentrations at the bases
  of the cellular plumes and that the phases of these ejections are
  uncorrelated from cell to cell. Thus, the large-scale motion is not a
  continuous flow, but is more like a system of independent conveyor belts
  all moving in the same direction along the magnetic field. In contrast,
  the proper motions in sunspots are clearly waves resulting from periodic
  disturbances in the sunspot umbras. The periods are ~2.6 minutes, but
  the sky-plane speeds and wavelengths depend on the heights of the waves
  above the sunspot. In the chromosphere, the waves decelerate from 35-45
  km s<SUP>-1</SUP> in the umbra to 7-8 km s<SUP>-1</SUP> toward the outer
  edge of the penumbra, but in the corona, the waves accelerate to ~60-100
  km s<SUP>-1</SUP>. Because chromospheric and coronal tracks originate
  from the same space/time locations, the coronal waves must emerge from
  the same umbral flashes that produce the chromospheric waves.

Title: Coronal Inflows during the Interval 1996-2014
Authors: Sheeley, N. R., Jr.; Wang, Y. -M.
Bibcode: 2014ApJ...797...10S
Altcode:
  We extend our previous counts of coronal inflows from the 5 yr interval
  1996-2001 to the 18 yr interval 1996-2014. By comparing stackplots
  of these counts with similar stackplots of the source-surface
  magnetic field and its longitudinal gradient, we find that the
  inflows occur in long-lived streams with counting rates in excess of
  18 inflows per day at sector boundaries where the gradient exceeds
  0.22 G rad<SUP>-1</SUP>. These streams are responsible for the high
  (86%) correlation between the inflow rate and the longitudinal
  field gradient. The overall inflow rate was several times larger in
  sunspot cycle 23 than it has been so far in cycle 24, reflecting the
  relatively weak source-surface fields during this cycle. By comparison,
  in cycles 21-22, the source-surface field and its gradient had bursts
  of great strength, as if large numbers of inflows occurred during
  those cycles. We find no obvious relation between inflows and coronal
  mass ejections (CMEs) on timescales of days to weeks, regardless of the
  speeds of the CMEs, and only a 60% correlation on timescales of months,
  provided the CMEs are fast (V &gt; 600 km s<SUP>-1</SUP>). We conclude
  that most of the flux carried out by CMEs is returned to the Sun via
  field line reconnection well below the 2.0 R <SUB>⊙</SUB> inner limit
  of the LASCO field of view, and that the remainder accumulates in the
  outer corona for an eventual return at sector boundaries.

Title: Origin of the Wang-Sheeley-Arge Solar Wind Model
Authors: Sheeley, Neil R.
Bibcode: 2014AAS...22420302S
Altcode:
  A correlation between solar wind speed at Earth and the amount of field
  line expansion in the corona was verified in 1989 using 22 years of
  solar and interplanetary observations. This talk will trace the history
  of this discovery from its birth 15 years earlier in the Skylab era
  to its current use as a space weather forecasting technique. This
  research was supported by NASA and ONR.

Title: Memories
Authors: Sheeley, N. R., Jr.
Bibcode: 2013ASPC..478...85S
Altcode:
  This paper highlights some events in solar research, beginning at
  Caltech in 1959 when Leighton described a technique for obtaining
  high-resolution observations of solar magnetic fields, and extending to
  1971 when his ideas were being pursued with the new spectroheliograph
  and 82 cm solar image at the Kitt Peak National Observatory.

Title: Using Coronal Cells to Infer the Magnetic Field Structure
    and Chirality of Filament Channels
Authors: Sheeley, N. R., Jr.; Martin, S. F.; Panasenco, O.; Warren,
   H. P.
Bibcode: 2013ApJ...772...88S
Altcode: 2013arXiv1306.2273S
  Coronal cells are visible at temperatures of ~1.2 MK in Fe XII
  coronal images obtained from the Solar Dynamics Observatory and Solar
  Terrestrial Relations Observatory spacecraft. We show that near a
  filament channel, the plumelike tails of these cells bend horizontally
  in opposite directions on the two sides of the channel like fibrils
  in the chromosphere. Because the cells are rooted in magnetic flux
  concentrations of majority polarity, these observations can be used
  with photospheric magnetograms to infer the direction of the horizontal
  field in filament channels and the chirality of the associated magnetic
  field. This method is similar to the procedure for inferring the
  direction of the magnetic field and the chirality of the fibril pattern
  in filament channels from Hα observations. However, the coronal cell
  observations are easier to use and provide clear inferences of the
  horizontal field direction for heights up to ~50 Mm into the corona.

Title: Fe XII Stalks and the Origin of the Axial Field in Filament
    Channels
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.; Stenborg, G.
Bibcode: 2013ApJ...770...72W
Altcode:
  Employing Fe XII images and line-of-sight magnetograms, we deduce
  the direction of the axial field in high-latitude filament channels
  from the orientation of the adjacent stalklike structures. Throughout
  the rising phase of the current solar cycle 24, filament channels
  poleward of latitude 30° overwhelmingly obeyed the hemispheric
  chirality rule, being dextral (sinistral) in the northern (southern)
  hemisphere, corresponding to negative (positive) helicity. During
  the deep minimum of 2007-2009, the orientation of the Fe XII stalks
  was often difficult to determine, but no obvious violations of the
  rule were found. Although the hemispheric trend was still present
  during the maximum and early declining phase of cycle 23 (2000-2003),
  several high-latitude exceptions were identified at that time. From
  the observation that dextral (sinistral) filament channels form
  through the decay of active regions whose Fe XII features show
  a counterclockwise (clockwise) whorl, we conclude that the axial
  field direction is determined by the intrinsic helicity of the active
  regions. In contrast, generation of the axial field component by the
  photospheric differential rotation is difficult to reconcile with the
  observed chirality of polar crown and circular filament channels, and
  with the presence of filament channels along the equator. The main role
  of differential rotation in filament channel formation is to expedite
  the cancellation of flux and thus the removal of the transverse field
  component. We propose further that, rather than being ejected into
  the heliosphere, the axial field is eventually resubmerged by flux
  cancellation as the adjacent unipolar regions become increasingly mixed.

Title: The Solar Wind and Interplanetary Field during Very Low
    Amplitude Sunspot Cycles
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 2013ApJ...764...90W
Altcode:
  Cosmogenic isotope records indicate that a solar-cycle modulation
  persists through extended periods of very low sunspot activity. One
  immediate implication is that the photospheric field during such grand
  minima did not consist entirely of ephemeral regions, which produce
  a negligible amount of open magnetic flux, but continued to have a
  large-scale component originating from active regions. Present-day
  solar and heliospheric observations show that the solar wind mass
  flux and proton density at the coronal base scale almost linearly
  with the footpoint field strength, whereas the wind speed at Earth is
  uncorrelated with the latter. Thus a factor of ~4-7 reduction in the
  total open flux, as deduced from reconstructions of the interplanetary
  magnetic field (IMF) during the Maunder Minimum, would lead to a
  similar decrease in the solar wind densities, while leaving the
  wind speeds largely unchanged. We also demonstrate that a decrease
  in the strengths of the largest active regions during grand minima
  will reduce the amplitude of the Sun's equatorial dipole relative to
  the axial component, causing the IMF strength to peak near sunspot
  minimum rather than near sunspot maximum, a result that is consistent
  with the phase shift observed in the <SUP>10</SUP>Be record during the
  Maunder Minimum. Finally, we discuss the origin of the 5 yr periodicity
  sometimes present in the cosmogenic isotope data during low and medium
  amplitude cycles.

Title: Calibrating 100 Years of Polar Faculae Measurements:
    Implications for the Evolution of the Heliospheric Magnetic Field
Authors: Muñoz-Jaramillo, Andrés; Sheeley, Neil R.; Zhang, Jie;
   DeLuca, Edward E.
Bibcode: 2012ApJ...753..146M
Altcode: 2013arXiv1303.0345M
  Although the Sun's polar magnetic fields are thought to provide
  important clues for understanding the 11 year sunspot cycle, including
  the observed variations of its amplitude and period, the current
  database of high-quality polar field measurements spans relatively
  few sunspot cycles. In this paper, we address this deficiency by
  consolidating Mount Wilson Observatory polar faculae data from four
  data reduction campaigns, validating it through a comparison with
  facular data counted automatically from Michelson Doppler Imager (MDI)
  intensitygrams, and calibrating it against polar field measurements
  taken by the Wilcox Solar Observatory and average polar field and
  total polar flux calculated using MDI line-of-sight magnetograms. Our
  results show that the consolidated polar facular measurements are in
  excellent agreement with both polar field and polar flux estimates,
  making them an ideal proxy to study the evolution of the polar
  magnetic field. Additionally, we combine this database with sunspot
  area measurements to study the role of the polar magnetic flux in the
  evolution of the heliospheric magnetic field (HMF). We find that there
  is a strong correlation between HMF and polar flux at solar minimum
  and that, taken together, polar flux and sunspot area are better
  at explaining the evolution of the HMF during the last century than
  sunspot area alone.

Title: The Longitudinal Properties of a Solar Energetic Particle
    Event Investigated Using Modern Solar Imaging
Authors: Rouillard, A. P.; Sheeley, N. R.; Tylka, A.; Vourlidas,
   A.; Ng, C. K.; Rakowski, C.; Cohen, C. M. S.; Mewaldt, R. A.; Mason,
   G. M.; Reames, D.; Savani, N. P.; StCyr, O. C.; Szabo, A.
Bibcode: 2012ApJ...752...44R
Altcode:
  We use combined high-cadence, high-resolution, and multi-point imaging
  by the Solar-Terrestrial Relations Observatory (STEREO) and the Solar
  and Heliospheric Observatory to investigate the hour-long eruption of a
  fast and wide coronal mass ejection (CME) on 2011 March 21 when the twin
  STEREO spacecraft were located beyond the solar limbs. We analyze the
  relation between the eruption of the CME, the evolution of an Extreme
  Ultraviolet (EUV) wave, and the onset of a solar energetic particle
  (SEP) event measured in situ by the STEREO and near-Earth orbiting
  spacecraft. Combined ultraviolet and white-light images of the lower
  corona reveal that in an initial CME lateral "expansion phase," the
  EUV disturbance tracks the laterally expanding flanks of the CME,
  both moving parallel to the solar surface with speeds of ~450 km
  s<SUP>-1</SUP>. When the lateral expansion of the ejecta ceases, the
  EUV disturbance carries on propagating parallel to the solar surface
  but devolves rapidly into a less coherent structure. Multi-point
  tracking of the CME leading edge and the effects of the launched
  compression waves (e.g., pushed streamers) give anti-sunward speeds
  that initially exceed 900 km s<SUP>-1</SUP> at all measured position
  angles. We combine our analysis of ultraviolet and white-light images
  with a comprehensive study of the velocity dispersion of energetic
  particles measured in situ by particle detectors located at STEREO-A
  (STA) and first Lagrange point (L1), to demonstrate that the delayed
  solar particle release times at STA and L1 are consistent with the
  time required (30-40 minutes) for the CME to perturb the corona over a
  wide range of longitudes. This study finds an association between the
  longitudinal extent of the perturbed corona (in EUV and white light)
  and the longitudinal extent of the SEP event in the heliosphere.

Title: Calibration Of a Century of Polar Field Measurements and
    what this Tells us About the Long-term Variability of the Solar and
    Heliospheric Magnetic Field
Authors: Munoz-Jaramillo, Andres; Sheeley, N. R.; Zhang, J.; DeLuca,
   E. E.
Bibcode: 2012AAS...22012304M
Altcode:
  In addition to the well known 11-year periodicity, the solar cycle also
  presents long-term modulations of its amplitude and period which play
  a determinant role in the evolution of space weather and climate. To
  this date, the efforts at understanding long-term solar variability
  have focused on the active parts of the cycle using sunspot properties
  as their main source of data. However, the recent extend minimum of
  sunspot cycle 23 has shown us that the quiet parts of the cycle are
  equally important and thus long-term databases complementary to sunspot
  properties are necessary. <P />Here we show how to consolidate Mount
  Wilson Observatory polar faculae data from four observational campaigns
  (1906-1964, Sheeley 1966; 1960-1975, Sheeley 1976; 1975-1990, Sheeley
  1991; 1985-2007, Sheeley 2008), validate it through a comparison
  with facular data counted automatically from MDI intensitygrams,
  and calibrate it against polar field measurements taken by the Wilcox
  Solar Observatory (1977-2011) and average polar field and total polar
  flux calculated using MDI line-of-sight magnetograms (1996-2011). <P
  />We also show that the consolidated polar facular measurements are
  in excellent agreement with both polar field and polar flux estimates,
  making them an ideal proxy to study the evolution of the polar magnetic
  field since 1906 and use this proxy to study the role of polar flux in
  the evolution of the solar cycle and the Heliospheric Magnetic Field
  (HMF).

Title: Coronal Cells
Authors: Sheeley, N. R., Jr.; Warren, H. P.
Bibcode: 2012ApJ...749...40S
Altcode:
  We have recently noticed cellular features in Fe XII 193 Å images of
  the 1.2 MK corona. They occur in regions bounded by a coronal hole
  and a filament channel, and are centered on flux elements of the
  photospheric magnetic network. Like their neighboring coronal holes,
  these regions have minority-polarity flux that is ~0.1-0.3 times
  their flux of majority polarity. Consequently, the minority-polarity
  flux is "grabbed" by the majority-polarity flux to form low-lying
  loops, and the remainder of the network flux escapes to connect with
  its opposite-polarity counterpart in distant active regions of the
  Sun. As these regions are carried toward the limb by solar rotation,
  the cells disappear and are replaced by linear plumes projecting toward
  the limb. In simultaneous views from the Solar Terrestrial Relations
  Observatory and Solar Dynamics Observatory spacecraft, these plumes
  project in opposite directions, extending away from the coronal hole in
  one view and toward the hole in the other view, suggesting that they are
  sky-plane projections of the same radial structures. We conclude that
  these regions are composed of closely spaced radial plumes, extending
  upward like candles on a birthday cake and visible as cells when seen
  from above. We suppose that a coronal hole has this same discrete,
  cellular magnetic structure, but that it is not seen until the
  encroachment of opposite-polarity flux closes part or all of the hole.

Title: On the Nature of the Solar Wind from Coronal Pseudostreamers
Authors: Wang, Y. -M.; Grappin, R.; Robbrecht, E.; Sheeley, N. R., Jr.
Bibcode: 2012ApJ...749..182W
Altcode:
  Coronal pseudostreamers, which separate like-polarity coronal holes, do
  not have current sheet extensions, unlike the familiar helmet streamers
  that separate opposite-polarity holes. Both types of streamers taper
  into narrow plasma sheets that are maintained by continual interchange
  reconnection with the adjacent open magnetic field lines. White-light
  observations show that pseudostreamers do not emit plasma blobs; this
  important difference from helmet streamers is due to the convergence
  of like-polarity field lines above the X-point, which prevents the
  underlying loops from expanding outward and pinching off. The main
  component of the pseudostreamer wind has the form of steady outflow
  along the open field lines rooted just inside the boundaries of the
  adjacent coronal holes. These flux tubes are characterized by very
  rapid expansion below the X-point, followed by reconvergence at greater
  heights. Analysis of an idealized pseudostreamer configuration shows
  that, as the separation between the underlying holes increases, the
  X-point rises and the expansion factor f <SUB>ss</SUB> at the source
  surface increases. In situ observations of pseudostreamer crossings
  indicate wind speeds v ranging from ~350 to ~550 km s<SUP>-1</SUP>,
  with O<SUP>7 +</SUP>/O<SUP>6 +</SUP> ratios that are enhanced compared
  with those in high-speed streams but substantially lower than in the
  slow solar wind. Hydrodynamic energy-balance models show that the
  empirical v-f <SUB>ss</SUB> relation overestimates the wind speeds
  from nonmonotonically expanding flux tubes, particularly when the
  X-point is located at low heights and f <SUB>ss</SUB> is small. We
  conclude that pseudostreamers produce a "hybrid" type of outflow that
  is intermediate between classical slow and fast solar wind.

Title: Observations of Reconnecting Flare Loops with the Atmospheric
    Imaging Assembly
Authors: Warren, Harry P.; O'Brien, Casey M.; Sheeley, Neil R., Jr.
Bibcode: 2011ApJ...742...92W
Altcode: 2011arXiv1109.2474W
  Perhaps the most compelling evidence for the role of magnetic
  reconnection in solar flares comes from the supra-arcade downflows that
  have been observed above many post-flare loop arcades. These downflows
  are thought to be related to highly non-potential field lines that have
  reconnected and are propagating away from the current sheet. We present
  new observations of supra-arcade downflows taken with the Atmospheric
  Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO). The
  morphology and dynamics of the downflows observed with AIA provide new
  evidence for the role of magnetic reconnection in solar flares. With
  these new observations we are able to measure downflows originating
  at larger heights than in previous studies. We find, however,
  that the initial velocities measured here (~144 km s<SUP>-1</SUP>)
  are well below the Alfvén speed expected in the lower corona, and
  consistent with previous results. We also find no evidence that the
  downflows brighten with time, as would be expected from chromospheric
  evaporation. These observations suggest that simple two-dimensional
  models cannot explain the detailed observations of solar flares.

Title: The longitudinal properties of solar energetic particle events
    investigated using modern solar imaging.
Authors: Rouillard, A. P.; Sheeley, N. R.; Tylka, A. J.; Vourlidas,
   A.; Ng, C. K.; Mason, G. M.; Cohen, C. M.
Bibcode: 2011AGUFMSH33D..03R
Altcode:
  On 2011 March 21, the Solar-Terrestrial Relations Observatory
  (STEREO) imaged the launch (at ~02:10UT) and outward propagation of
  a fast (&gt;1300 km s-1) and wide (latitudinal extent greater than
  90 degrees) coronal mass ejection (CME) which emerged W135 degrees
  (behind the west-limb as viewed from near-Earth spacecraft). Protons
  with energies exceeding 90 MeV were first detected by the STEREO-Ahead
  (STA) spacecraft and a few minutes later by near-Earth orbiting
  spacecraft. Velocity dispersion analyses of energetic electrons, protons
  and heavier ions, put the solar particle release (SPR) times along
  magnetic field lines connected to STA at ~02:30UT and along magnetic
  field lines connected to near-Earth spacecraft at ~ 03:00UT. The
  spatial evolution of a pressure wave and its associated shock forming
  around the CME could be tracked using (critical) high-cadence and
  high-resolution STA (extreme ultraviolet and white-light) images. We
  demonstrate that the delay between the SEP onset at STA and Earth is
  consistent with the time required for the pressure wave to propagate
  from the launch-site of the CME to the base of coronal streamers that
  are magnetically connected to near-Earth spacecraft. By considering
  measured shock speeds and inferred shock geometries along different
  longitudes and by deriving spectra of energetic protons, this study
  also presents some interpretation of the longitudinal variability of
  the SEP event in terms of the evolution of the compression wave. Time
  permitting, we will also summarise the results of similar analyses
  carried out for the other energetic CME events in 2010 and 2011.

Title: Observations of the White Light Corona from Solar Orbiter
    and Solar Probe Plus
Authors: Howard, R. A.; Thernisien, A. F.; Vourlidas, A.; Plunkett,
   S. P.; Korendyke, C. M.; Sheeley, N. R.; Morrill, J. S.; Socker,
   D. G.; Linton, M. G.; Liewer, P. C.; De Jong, E. M.; Velli, M. M.;
   Mikic, Z.; Bothmer, V.; Lamy, P. L.
Bibcode: 2011AGUFMSH43F..06H
Altcode:
  The SoloHI instrument on Solar Orbiter and the WISPR instrument on Solar
  Probe+ will make white light coronagraphic images of the corona as the
  two spacecraft orbit the Sun. The minimum perihelia for Solar Orbiter
  is about 60 Rsun and for SP+ is 9.5 Rsun. The wide field of view of the
  WISPR instrument (about 105 degrees radially) corresponds to viewing
  the corona from 2.2 Rsun to 20 Rsun. Thus the entire Thomson hemisphere
  is contained within the telescope's field and we need to think of
  the instrument as being a traditional remote sensing instrument and
  then transitioning to a local in-situ instrument. The local behavior
  derives from the fact that the maximum Thomson scattering will favor
  the electron plasma close to the spacecraft - exactly what the in-situ
  instruments will be sampling. SoloHI and WISPR will also observe
  scattered light from dust in the inner heliosphere, which will be an
  entirely new spatial regime for dust observations from a coronagraph,
  which we assume to arise from dust in the general neighborhood of about
  half way between the observer and the Sun. As the dust grains approach
  the Sun, they evaporate and do not contribute to the scattering. A
  dust free zone has been postulated to exist somewhere inside of 5 Rsun
  where all dust is evaporated, but this has never been observed. The
  radial position where the evaporation occurs will depend on the
  precise molecular composition of the individual grains. The orbital
  plane of Solar Orbiter will gradually increase up to about 35 degrees,
  enabling a very different view through the zodiacal dust cloud to test
  the models generated from in-ecliptic observations. In this paper we
  will explore some of the issues associated with the observation of
  the dust and will present a simple model to explore the sensitivity
  of the instrument to observe such evaporations.

Title: Interpreting the Properties of Solar Energetic Particle Events
    by Using Combined Imaging and Modeling of Interplanetary Shocks
Authors: Rouillard, A. P.; Odstřcil, D.; Sheeley, N. R.; Tylka, A.;
   Vourlidas, A.; Mason, G.; Wu, C. -C.; Savani, N. P.; Wood, B. E.;
   Ng, C. K.; Stenborg, G.; Szabo, A.; St. Cyr, O. C.
Bibcode: 2011ApJ...735....7R
Altcode:
  Images of the solar corona obtained by the Solar-Terrestrial Relations
  Observatory (STEREO) provide high-cadence, high-resolution observations
  of a compression wave forming ahead of a fast (940 km s<SUP>-1</SUP>)
  coronal mass ejection (CME) that erupted at ~9:00 UT on 2010 April
  03. The passage of this wave at 1 AU is detected in situ by the Advanced
  Composition Explorer and Wind spacecraft at 08:00 UT on April 05 as a
  shock followed by a turbulent and heated sheath. These unprecedented and
  complementary observations of a shock-sheath region from the Sun to 1 AU
  are used to investigate the onset of a Solar Energetic Particle (SEP)
  event measured at the first Lagrange point (L1) and at STEREO-Behind
  (STB). The spatial extent, radial coordinates, and speed of the ejection
  are measured from STEREO observations and used as inputs to a numerical
  simulation of the CME propagation in the background solar wind. The
  simulated magnetic and plasma properties of the shock and sheath region
  at L1 agree very well with the in situ measurements. These simulation
  results reveal that L1 and STB are magnetically connected to the western
  and eastern edges of the driven shock, respectively. They also show
  that the 12 hr delay between the eruption time of the ejection and the
  SEP onset at L1 corresponds to the time required for the bow shock to
  reach the magnetic field lines connected with L1. The simulated shock
  compression ratio increases along these magnetic field lines until
  the maximum flux of high-energy particles is observed.

Title: The Solar Origin of Small Interplanetary Transients
Authors: Rouillard, A. P.; Sheeley, N. R., Jr.; Cooper, T. J.; Davies,
   J. A.; Lavraud, B.; Kilpua, E. K. J.; Skoug, R. M.; Steinberg, J. T.;
   Szabo, A.; Opitz, A.; Sauvaud, J. -A.
Bibcode: 2011ApJ...734....7R
Altcode:
  In this paper, we present evidence for magnetic transients with
  small radial extents ranging from 0.025 to 0.118 AU measured in
  situ by the Solar-Terrestrial Relations Observatory (STEREO) and the
  near-Earth Advanced Composition Explorer (ACE) and Wind spacecraft. The
  transients considered in this study are much smaller (&lt;0.12 AU)
  than the typical sizes of magnetic clouds measured near 1 AU (~0.23
  AU). They are marked by low plasma beta values, generally lower magnetic
  field variance, short timescale magnetic field rotations, and are all
  entrained by high-speed streams by the time they reach 1 AU. We use
  this entrainment to trace the origin of these small interplanetary
  transients in coronagraph images. We demonstrate that these magnetic
  field structures originate as either small or large mass ejecta. The
  small mass ejecta often appear from the tip of helmet streamers as
  arch-like structures and other poorly defined white-light features (the
  so-called blobs). However, we have found a case of a small magnetic
  transient tracing back to a small and narrow mass ejection erupting
  from below helmet streamers. Surprisingly, one of the small magnetic
  structures traces back to a large mass ejection; in this case, we show
  that the central axis of the coronal mass ejection is along a different
  latitude and longitude to that of the in situ spacecraft. The small
  size of the transient is related to the in situ measurements being
  taken on the edges or periphery of a larger magnetic structure. In
  the last part of the paper, an ejection with an arch-like aspect is
  tracked continuously to 1 AU in the STEREO images. The associated in
  situ signature is not that of a magnetic field rotation but rather
  of a temporary reversal of the magnetic field direction. Due to its
  "open-field topology," we speculate that this structure is partly formed
  near helmet streamers due to reconnection between closed and open
  magnetic field lines. The implications of these observations for our
  understanding of the variability of the slow solar wind are discussed.

Title: Carrington Maps of Ca II K-line Emission for the Years
    1915-1985
Authors: Sheeley, N. R., Jr.; Cooper, T. J.; Anderson, J. R. L.
Bibcode: 2011ApJ...730...51S
Altcode:
  We have used Mount Wilson Observatory calcium K-line images, digitized
  and flat fielded by the solar group at UCLA, to construct Carrington
  maps of Ca II 3934 Å intensity for the years 1915-1985. These maps have
  a spatial resolution comparable to the resolution of Carrington maps
  of the magnetic field observed at Kitt Peak and a spectral resolution
  comparable to the width of the K<SUB>232</SUB> emission. Consequently,
  they provide a way of tracking the spatial distribution of magnetic
  flux from the present back to the year 1915. In this paper, we compare
  some of the recent K-line maps with corresponding maps of magnetic
  field, and show examples of K-line maps during earlier sunspot
  cycles when high-quality magnetograms were not available. Then, we
  use butterfly diagrams and super-synoptic displays to summarize the
  long-term evolution of the patterns of calcium intensity. Although each
  cycle has characteristics that are similar to the others, cycle 19 is
  remarkable for its broad latitudinal distribution of active regions,
  for its giant poleward surges of flux, and for the emergence of a
  north-south asymmetry that lasted 10 years.

Title: The Wide Field Imager for Solar PRobe (WISPR)
Authors: Plunkett, S. P.; Howard, R. A.; Vourlidas, A.; Korendyke,
   C. M.; Socker, D. G.; Morrill, J. S.; Sheeley, N. R.; Linton, M.;
   Liewer, P. C.; de Jong, E. M.; Mikic, Z.
Bibcode: 2010AGUFMSH11B1622P
Altcode:
  The Wide Field Imager for Solar PRobe (WISPR) will image the
  Thomson-scattered light from the coronal plasma in the inner corona,
  with unprecedented spatial resolution, cadence, and sensitivity. WISPR
  follows on the SECCHI Heliospheric Imager (HI) aboard the STEREO
  mission, and addresses all four key objectives in the Solar Probe Plus:
  Report of the STDT (2008): (1) Determine the structure and dynamics of
  the magnetic fields at the sources of the fast and slow solar wind, (2)
  Trace the flow of energy that heats the solar corona and accelerates
  the SW, (3) explore the mechanisms that accelerate and transport
  energetic particles, (4) explore dusty plasma phenomena and their
  influence on the solar wind and energetic particle formation. Situated
  in the ram direction of the Solar Probe Plus (SPP) spacecraft (S/C),
  WISPR will have the unique ability to image the coronal structures when
  they are close to the Sun, as they approach, and as they pass over the
  spacecraft. As a remote sensor, WISPR will connect the structures close
  to the Sun to the spacecraft and provide important spatial and temporal
  information; measuring, for example, the properties of the structures
  generating the shocks and SEPs that will be measured in a few minutes at
  the S/C. Since the S/C is embedded in the corona, WISPR and the in situ
  instruments will measure for the first time the same plasma. Also as
  the SPP transits through the corona, the rapidly-varying viewpoint and
  high spatial resolution of WISPR will enable tomographic imaging of the
  corona, and lead to higher fidelity and finer scale 3D reconstructions
  than are possible with the STEREO mission or single-view rotational
  tomography. The wide field of view will include at times other inner
  heliospheric probes (e.g. Solar Orbiter) and will image the outflowing
  wind that is impinging on that probe. In addition to this standard
  imaging mode, WISPR opens a new capability for imaging instruments,
  the measurement of pressure turbulence by employing a high cadence mode
  (~1 sec) to image a small region in the corona. For the first time,
  the slopes of the power spectral density from images can be compared
  directly to the density and magnetic field fluctuations seen in situ as
  a function of coronal spatial structure and heliocentric distance. In
  addition, the 1 sec cadence can be generated anywhere within the WISPR
  field, enabling the study of the transition of the solar wind injected
  at the tops of the helmet streamers to inertial dissipation scales.

Title: White Light and In Situ Comparison of a Forming Merged
    Interaction Region
Authors: Rouillard, A. P.; Lavraud, B.; Sheeley, N. R.; Davies, J. A.;
   Burlaga, L. F.; Savani, N. P.; Jacquey, C.; Forsyth, R. J.
Bibcode: 2010ApJ...719.1385R
Altcode:
  The images taken by the Heliospheric Imager (HI) instruments, part of
  the SECCHI imaging package on board the pair of STEREO spacecraft,
  provide information on the radial and latitudinal evolution of the
  plasma transported by coronal mass ejections (CMEs). In this case
  study, a CME, appearing near 15 UT on 2007 November 15 in SECCHI
  coronagraph images, leads to the formation of two out-flowing density
  structures (DSs) in the heliosphere. The analysis of time-elongation
  maps constructed from images obtained by the HI instruments shows that
  these DSs were propagating along the Sun-Earth line. A direct comparison
  of HI images and in situ measurements taken near Earth could therefore
  be performed. These two DSs are separated by a cavity associated with
  little brightness variation or equivalently little electron density
  variation. In situ measurements made in the solar wind near Earth on
  2007 November 20 show that this cavity corresponds to a magnetic cloud
  (MC). While the leading DS is related to the sheath in front of the MC,
  the second DS is located on the sunward side of the MC where high-speed
  solar wind from a coronal hole catches up and interacts with the MC. We
  conclude that HI observes the sub-structures of a merged interaction
  region (MIR), a region of the interplanetary medium where the total
  solar wind pressure is greatly enhanced by the interaction of an MC
  with the ambient solar wind. This MIR caused the largest geomagnetic
  storm in 2007.

Title: Observations of the magnetic field and plasma in the
    heliosheath by Voyager 2 from 2007.7 to 2009.4
Authors: Burlaga, L. F.; Ness, N. F.; Wang, Y. -M.; Sheeley, N. R.;
   Richardson, J. D.
Bibcode: 2010JGRA..115.8107B
Altcode: 2010JGRA..11508107B
  The density and temperature profiles of the plasma measured by Voyager
  2 (V2) behind the termination shock changed abruptly near 2008.6
  from relatively large average values and large fluctuations during
  2007.7 to 2008.6 (interval A) to relatively low average values and
  very small-amplitude fluctuations during 2008.6 to 2009.4 (interval
  B). This paper shows that the change in the magnetic field strength B(t)
  was less abrupt than the plasma changes, and the fluctuations of the
  magnetic field strength in interval B were of moderate amplitude, with
  indications of a quasiperiodic structure in part of the interval. The
  magnetic field was directed away from the sun (positive polarity)
  ∼ 78% ± 5% of the time in both interval A and interval B, changing
  in an irregular way from positive to negative polarities throughout
  the interval. The polarity distribution indicates that the minimum
  latitudinal extent of the heliospheric current sheet (HCS) was
  near V2 throughout the interval, consistent with the extrapolated
  minimum latitudes of the HCS computed from solar magnetic field
  observations. Thus, V2 was observing magnetic fields from the southern
  polar coronal hole most of the time. The distribution of B was lognormal
  in interval A and Gaussian interval B.

Title: On the "Extended" Solar Cycle in Coronal Emission
Authors: Robbrecht, E.; Wang, Y. -M.; Sheeley, N. R., Jr.; Rich, N. B.
Bibcode: 2010ApJ...716..693R
Altcode:
  Butterfly diagrams (latitude-time plots) of coronal emission show a
  zone of enhanced brightness that appears near the poles just after
  solar maximum and migrates toward lower latitudes; a bifurcation seems
  to occur at sunspot minimum, with one branch continuing to migrate
  equatorward with the sunspots of the new cycle and the other branch
  heading back to the poles. The resulting patterns have been likened to
  those seen in torsional oscillations and have been taken as evidence
  for an extended solar cycle lasting over ~17 yr. In order to clarify
  the nature of the overlapping bands of coronal emission, we construct
  butterfly diagrams from green-line simulations covering the period
  1967-2009 and from 19.5 nm and 30.4 nm observations taken with the
  Extreme-Ultraviolet Imaging Telescope during 1996-2009. As anticipated
  from earlier studies, we find that the high-latitude enhancements mark
  the footpoint areas of closed loops with one end rooted outside the
  evolving boundaries of the polar coronal holes. The strong underlying
  fields were built up over the declining phase of the cycle through
  the poleward transport of active-region flux by the surface meridional
  flow. Rather than being a precursor of the new-cycle sunspot activity
  zone, the high-latitude emission forms a physically distinct, U-shaped
  band that curves upward again as active-region fields emerge at
  midlatitudes and reconnect with the receding polar-hole boundaries. We
  conclude that the so-called extended cycle in coronal emission is a
  manifestation not of early new-cycle activity, but of the poleward
  concentration of old-cycle trailing-polarity flux by meridional flow.

Title: What's So Peculiar about the Cycle 23/24 Solar Minimum?
Authors: Sheeley, N. R., Jr.
Bibcode: 2010ASPC..428....3S
Altcode: 2010arXiv1005.3834S
  Traditionally, solar physicists become anxious around solar minimum,
  as they await the high-latitude sunspot groups of the new cycle. Now,
  we are in an extended sunspot minimum with conditions not seen in recent
  memory, and interest in the sunspot cycle has increased again. In this
  paper, I will describe some of the characteristics of the current solar
  minimum, including its great depth, its extended duration, its weak
  polar magnetic fields, and its small amount of open flux. Flux transport
  simulations suggest that these characteristics are a consequence of
  temporal variations of the Sun's large-scale meridional circulation.

Title: Tracking Streamer Blobs into the Heliosphere
Authors: Sheeley, N. R., Jr.; Rouillard, A. P.
Bibcode: 2010ApJ...715..300S
Altcode: 2010arXiv1006.5379S
  In this paper, we use coronal and heliospheric images from the Solar
  Terrestrial Relations Observatory (STEREO) spacecraft to track streamer
  blobs into the heliosphere and to observe them being swept up and
  compressed by the fast wind from low-latitude coronal holes. From an
  analysis of their elongation/time tracks, we discover a "locus of
  enhanced visibility" where neighboring blobs pass each other along
  the line of sight and their corotating spiral is seen edge-on. The
  detailed shape of this locus accounts for a variety of east-west
  asymmetries and allows us to recognize the spiral of blobs by its
  signatures in the STEREO images: in the eastern view from STEREO-A,
  the leading edge of the spiral is visible as a moving wavefront where
  foreground ejections overtake background ejections against the sky
  and then fade. In the western view from STEREO-B, the leading edge is
  only visible close to the Sun-spacecraft line where the radial path
  of ejections nearly coincides with the line of sight. In this case,
  we can track large-scale waves continuously back to the lower corona
  and see that they originate as face-on blobs.

Title: Formation and Evolution of Coronal Holes Following the
    Emergence of Active Regions
Authors: Wang, Y. -M.; Robbrecht, E.; Rouillard, A. P.; Sheeley,
   N. R., Jr.; Thernisien, A. F. R.
Bibcode: 2010ApJ...715...39W
Altcode:
  The low level of solar activity over the past four years has provided
  unusually favorable conditions for tracking the formation and evolution
  of individual coronal holes and their wind streams. Employing
  extreme-ultraviolet images recorded with the Solar Terrestrial
  Relations Observatory during 2007-2009, we analyze three cases
  in which small coronal holes first appear at the edges of newly
  emerged active regions and then expand via flux transport processes,
  eventually becoming attached to the polar holes. The holes form
  gradually over timescales comparable to or greater than that for
  the active regions to emerge, without any obvious association with
  coronal mass ejections. The evolving hole areas coincide approximately
  with the footpoints of open field lines derived from potential-field
  source-surface extrapolations of the photospheric field. One of these
  coronal-hole systems, centered at the equator and maintained by a
  succession of old-cycle active regions emerging in the same longitude
  range, persists in one form or another for up to two years. The other
  two holes, located at midlatitudes and originating from new-cycle
  active regions, become strongly sheared and decay away after a few
  rotations. The hole boundaries and the small active-region holes, both
  of which are sources of slow wind, are observed to undergo continual
  short-term (lsim1 day) fluctuations on spatial scales comparable to
  that of the supergranulation. From in situ measurements, we identify
  a number of plasma sheets associated with pseudostreamers separating
  holes of the same polarity.

Title: Intermittent release of transients in the slow solar wind:
    1. Remote sensing observations
Authors: Rouillard, A. P.; Davies, J. A.; Lavraud, B.; Forsyth, R. J.;
   Savani, N. P.; Bewsher, D.; Brown, D. S.; Sheeley, N. R.; Davis,
   C. J.; Harrison, R. A.; Howard, R. A.; Vourlidas, A.; Lockwood, M.;
   Crothers, S. R.; Eyles, C. J.
Bibcode: 2010JGRA..115.4103R
Altcode: 2010JGRA..11504103R
  The Heliospheric Imager (HI) instruments on board the STEREO spacecraft
  are used to analyze the solar wind during August and September 2007. We
  show how HI can be used to image the streamer belt and, in particular,
  the variability of the slow solar wind which originates inside and
  in the vicinity of the streamer belt. Intermittent mass flows are
  observed in HI difference images, streaming out along the extension of
  helmet streamers. These flows can appear very differently in images:
  plasma distributed on twisted flux ropes, V-shaped structures, or
  “blobs.” The variety of these transient features may highlight the
  richness of phenomena that could occur near helmet streamers: emergence
  of flux ropes, reconnection of magnetic field lines at the tip of
  helmet streamers, or disconnection of open magnetic field lines. The
  plasma released with these transient events forms part of the solar
  wind in the higher corona; HI observations show that these transients
  are frequently entrained by corotating interaction regions (CIRs),
  leading to the formation of larger, brighter plasma structures in HI
  images. This entrainment is used to estimate the trajectory of these
  plasma ejecta. In doing so, we demonstrate that successive transients
  can be entrained by the same CIR in the high corona if they emanate
  from the same corotating source. Some parts of the streamers are more
  effective sources of transients than others. Surprisingly, evidence
  is given for the outflow of a recurring twisted magnetic structure,
  suggesting that the emergence of flux ropes can be recurrent.

Title: On the Weakening of the Polar Magnetic Fields during Solar
    Cycle 23
Authors: Wang, Y. -M.; Robbrecht, E.; Sheeley, N. R., Jr.
Bibcode: 2009ApJ...707.1372W
Altcode:
  The Sun's polar fields are currently ~40% weaker than they were during
  the previous three sunspot minima. This weakening has been accompanied
  by a corresponding decrease in the interplanetary magnetic field (IMF)
  strength, by a ~20% shrinkage in the polar coronal-hole areas, and by
  a reduction in the solar-wind mass flux over the poles. It has also
  been reflected in coronal streamer structure and the heliospheric
  current sheet, which only showed the expected flattening into the
  equatorial plane after sunspot numbers fell to unusually low values
  in mid-2008. From latitude-time plots of the photospheric field,
  it has long been apparent that the polar fields are formed through
  the transport of trailing-polarity flux from the sunspot latitudes
  to the poles. To address the question of why the polar fields are
  now so weak, we simulate the evolution of the photospheric field and
  radial IMF strength from 1965 to the present, employing a surface
  transport model that includes the effects of active region emergence,
  differential rotation, supergranular convection, and a poleward bulk
  flow. We find that the observed evolution can be reproduced if the
  amplitude of the surface meridional flow is varied by as little as 15%
  (between 14.5 and 17 m s<SUP>-1</SUP>), with the higher average speeds
  being required during the long cycles 20 and 23.

Title: A solar storm observed from the Sun to Venus using the STEREO,
    Venus Express, and MESSENGER spacecraft
Authors: Rouillard, A. P.; Davies, J. A.; Forsyth, R. J.; Savani,
   N. P.; Sheeley, N. R.; Thernisien, A.; Zhang, T. -L.; Howard, R. A.;
   Anderson, B.; Carr, C. M.; Tsang, S.; Lockwood, M.; Davis, C. J.;
   Harrison, R. A.; Bewsher, D.; Fränz, M.; Crothers, S. R.; Eyles,
   C. J.; Brown, D. S.; Whittaker, I.; Hapgood, M.; Coates, A. J.; Jones,
   G. H.; Grande, M.; Frahm, R. A.; Winningham, J. D.
Bibcode: 2009JGRA..114.7106R
Altcode: 2009JGRA..11407106R
  The suite of SECCHI optical imaging instruments on the STEREO-A
  spacecraft is used to track a solar storm, consisting of several coronal
  mass ejections (CMEs) and other coronal loops, as it propagates from
  the Sun into the heliosphere during May 2007. The 3-D propagation
  path of the largest interplanetary CME (ICME) is determined from the
  observations made by the SECCHI Heliospheric Imager (HI) on STEREO-A
  (HI-1/2A). Two parts of the CME are tracked through the SECCHI images, a
  bright loop and a V-shaped feature located at the rear of the event. We
  show that these two structures could be the result of line-of-sight
  integration of the light scattered by electrons located on a single
  flux rope. In addition to being imaged by HI, the CME is observed
  simultaneously by the plasma and magnetic field experiments on the Venus
  Express and MESSENGER spacecraft. The imaged loop and V-shaped structure
  bound, as expected, the flux rope observed in situ. The SECCHI images
  reveal that the leading loop-like structure propagated faster than
  the V-shaped structure, and a decrease in in situ CME speed occurred
  during the passage of the flux rope. We interpret this as the result
  of the continuous radial expansion of the flux rope as it progressed
  outward through the interplanetary medium. An expansion speed in the
  radial direction of ∼30 km s<SUP>-1</SUP> is obtained directly from
  the SECCHI-HI images and is in agreement with the difference in speed
  of the two structures observed in situ. This paper shows that the flux
  rope location can be determined from white light images, which could
  have important space weather applications.

Title: Radial and solar cycle variations of the magnetic fields in
the heliosheath: Voyager 1 observations from 2005 to 2008
Authors: Burlaga, L. F.; Ness, N. F.; Acuña, M. H.; Wang, Y. -M.;
   Sheeley, N. R.
Bibcode: 2009JGRA..114.6106B
Altcode: 2009JGRA..11406106B
  We discuss the magnetic field strength B(t) and polarity observed by
  Voyager 1 (V1) in the heliosheath at the heliographic latitude ≈34°
  as it moved away from the Sun from 2005 through 2008.82 (where 2008.0
  is the beginning of 1 January 2008). The pattern of the polarity of the
  magnetic field changed from alternating positive and negative polarities
  to predominantly negative polarities (magnetic fields pointing along
  the Archimedean spiral field angle toward the Sun) at ≈2006.23). This
  transition indicates that the latitudinal extent of the heliospheric
  current sheet (HCS) was decreasing in the supersonic solar wind, as
  expected for the declining phase of the solar cycle, and as predicted
  by extrapolation of the magnetic neutral line near the photosphere to
  the position of V1. However, the polarity was not uniformly negative
  in during 2008, in contrast to the predicted polarity. This difference
  suggests that the maximum latitudinal extent of the HCS was tending
  to increase in the northern hemisphere in the heliosheath, while it
  was decreasing in the supersonic solar wind. The large-scale magnetic
  field strength B(t) was observed by V1 from 2005 through 2008.82. During
  this interval of decreasing solar activity toward solar minimum, B(t)
  at 1 AU was decreasing, and the solar wind speed V at the latitude of
  V1 was increasing. Adjusting the temporal profile of B(t) observed by V1
  for the solar cycle variations of B and V in the supersonic solar wind,
  we find that the radial gradient of B(R) in heliosheath from the radial
  distance R = 94.2 AU to 107.9 AU between 2005.0 and 2008.82 was 0.0017
  nT/AU ≤ grad B ≤ 0.0055 nT/AU, or grad B = (0.0036 ± 0.0019) nT/AU.

Title: Remote-sensing Observations of the Corona and Solar Wind
Authors: Sheeley, Neil R., Jr.
Bibcode: 2009AAS...21410701S
Altcode:
  On June 25, 1908, George Ellery Hale used the 60-foot Tower Telescope
  on Mount Wilson to make the first measurements of magnetic fields
  in sunspots. This began a series of studies that led to Hale's Law
  of sunspot polarities and established the Mount Wilson Observatory
  as a leading center of solar magnetic field research. The magnetic
  aura was still present in 1962 when I began solar research there as a
  Caltech graduate student. Mount Wilson astronomer Horace Babcock and
  his father had invented the solar magnetograph, discovered the polar
  fields of the Sun, and observed their reversal near the 1958 sunspot
  maximum. Caltech physicist Robert Leighton had added new instrumentation
  to the Mount Wilson spectroheliograph and obtained high-resolution
  maps of the magnetic field. Babcock had just published his classic
  paper on the topology of the field and its 22-year cycle. The paper
  contained a sketch, illustrating the coronal field-line reconnection,
  which he thought must occur in response to changes of the photospheric
  field. Some loops flew away in the yet-to-be-discovered solar wind
  and other loops collapsed back to the Sun. <P />In this talk, I will
  present new observations from the SOHO and STEREO spacecraft, which
  show such coronal changes. Loops stretch out in the expanding corona
  and tear away from the Sun like drops from a leaky faucet. Simultaneous
  observations with different perspectives show that the detached loops
  are really helices in 3-D. Off-pointed heliospheric imagers allow us
  to track these ejections outward past planets (including Earth) and
  comets, and to observe their compression into a heliospheric spiral,
  as a consequence of longitudinal speed gradients on the rotating
  Sun. And XUV observations of the solar disk show brightness changes
  associated with reconnections high in the corona, like auroral displays
  in the magnetosphere.

Title: A Multispacecraft Analysis of a Small-Scale Transient Entrained
    by Solar Wind Streams
Authors: Rouillard, A. P.; Savani, N. P.; Davies, J. A.; Lavraud, B.;
   Forsyth, R. J.; Morley, S. K.; Opitz, A.; Sheeley, N. R.; Burlaga,
   L. F.; Sauvaud, J. -A.; Simunac, K. D. C.; Luhmann, J. G.; Galvin,
   A. B.; Crothers, S. R.; Davis, C. J.; Harrison, R. A.; Lockwood, M.;
   Eyles, C. J.; Bewsher, D.; Brown, D. S.
Bibcode: 2009SoPh..256..307R
Altcode:
  The images taken by the Heliospheric Imagers (HIs), part of the
  SECCHI imaging package onboard the pair of STEREO spacecraft,
  provide information on the radial and latitudinal evolution of the
  plasma compressed inside corotating interaction regions (CIRs). A
  plasma density wave imaged by the HI instrument onboard STEREO-B was
  found to propagate towards STEREO-A, enabling a comparison between
  simultaneous remote-sensing and in situ observations of its structure to
  be performed. In situ measurements made by STEREO-A show that the plasma
  density wave is associated with the passage of a CIR. The magnetic
  field compressed after the CIR stream interface (SI) is found to have
  a planar distribution. Minimum variance analysis of the magnetic field
  vectors shows that the SI is inclined at 54° to the orbital plane of
  the STEREO-A spacecraft. This inclination of the CIR SI is comparable
  to the inclination of the associated plasma density wave observed by
  HI. A small-scale magnetic cloud with a flux rope topology and radial
  extent of 0.08 AU is also embedded prior to the SI. The pitch-angle
  distribution of suprathermal electrons measured by the STEREO-A SWEA
  instrument shows that an open magnetic field topology in the cloud
  replaced the heliospheric current sheet locally. These observations
  confirm that HI observes CIRs in difference images when a small-scale
  transient is caught up in the compression region.

Title: Two Years of the STEREO Heliospheric Imagers. Invited Review
Authors: Harrison, Richard A.; Davies, Jackie A.; Rouillard, Alexis
   P.; Davis, Christopher J.; Eyles, Christopher J.; Bewsher, Danielle;
   Crothers, Steve R.; Howard, Russell A.; Sheeley, Neil R.; Vourlidas,
   Angelos; Webb, David F.; Brown, Daniel S.; Dorrian, Gareth D.
Bibcode: 2009SoPh..256..219H
Altcode:
  Imaging of the heliosphere is a burgeoning area of research. As
  a result, it is awash with new results, using novel applications,
  and is demonstrating great potential for future research in a wide
  range of topical areas. The STEREO (Solar TErrestrial RElations
  Observatory) Heliospheric Imager (HI) instruments are at the heart
  of this new development, building on the pioneering observations of
  the SMEI (Solar Mass Ejection Imager) instrument aboard the Coriolis
  spacecraft. Other earlier heliospheric imaging systems have included
  ground-based interplanetary scintillation (IPS) facilities and the
  photometers on the Helios spacecraft. With the HI instruments, we now
  have routine wide-angle imaging of the inner heliosphere, from vantage
  points outside the Sun-Earth line. HI has been used to investigate the
  development of coronal mass ejections (CMEs) as they pass through the
  heliosphere to 1 AU and beyond. Synoptic mapping has also allowed us to
  see graphic illustrations of the nature of mass outflow as a function
  of distance from the Sun - in particular, stressing the complexity of
  the near-Sun solar wind. The instruments have also been used to image
  co-rotating interaction regions (CIRs), to study the interaction of
  comets with the solar wind and CMEs, and to witness the impact of CMEs
  and CIRs on planets. The very nature of this area of research - which
  brings together aspects of solar physics, space-environment physics,
  and solar-terrestrial physics - means that the research papers are
  spread among a wide range of journals from different disciplines. Thus,
  in this special issue, it is timely and appropriate to provide a review
  of the results of the first two years of the HI investigations.

Title: Remote-sensing Observations of the Corona and Solar Wind
Authors: Sheeley, Neil R., Jr.
Bibcode: 2009SPD....40.2801S
Altcode:
  On June 25, 1908, George Ellery Hale used the 60-foot Tower Telescope
  on Mount Wilson to make the first measurements of magnetic fields
  in sunspots. This began a series of studies that led to Hale's Law
  of sunspot polarities and established the Mount Wilson Observatory
  as a leading center of solar magnetic field research. The magnetic
  aura was still present in 1962 when I began solar research there as a
  Caltech graduate student. Mount Wilson astronomer Horace Babcock and
  his father had invented the solar magnetograph, discovered the polar
  fields of the Sun, and observed their reversal near the 1958 sunspot
  maximum. Caltech physicist Robert Leighton had added new instrumentation
  to the Mount Wilson spectroheliograph and obtained high-resolution
  maps of the magnetic field. Babcock had just published his classic
  paper on the topology of the field and its 22-year cycle. The paper
  contained a sketch, illustrating the coronal field-line reconnection,
  which he thought must occur in response to changes of the photospheric
  field. Some loops flew away in the yet-to-be-discovered solar wind
  and other loops collapsed back to the Sun. <P />In this talk, I will
  present new observations from the SOHO and STEREO spacecraft, which
  show such coronal changes. Loops stretch out in the expanding corona
  and tear away from the Sun like drops from a leaky faucet. Simultaneous
  observations with different perspectives show that the detached loops
  are really helices in 3-D. Off-pointed heliospheric imagers allow us
  to track these ejections outward past planets (including Earth) and
  comets, and to observe their compression into a heliospheric spiral,
  as a consequence of longitudinal speed gradients on the rotating
  Sun. And XUV observations of the solar disk show brightness changes
  associated with reconnections high in the corona, like auroral displays
  in the magnetosphere.

Title: White-light and in-situ observations of an Earth-impacting
    CME using the STEREO spacecraft
Authors: Rouillard, A. P.; Savani, N. P.; Sheeley, N. R.; Burlaga,
   L. F.; Lavraud, B.; Davies, J. A.; Forsyth, R. J.; Davis, C.;
   Lockwood, M.
Bibcode: 2009EGUGA..11.8052R
Altcode:
  We use the heliospheric imagers (HIs) onboard the STEREO A and B
  spacecraft to analyse the propagation of an Earth-impacting Coronal
  Mass Ejection (CME) during November 2007. The transient is observed
  continuously in white-light images from the Sun to 1 AU. The 3-D
  propagation path is determined and a method is outlined to obtain the
  acceleration profile of the transient. The CME comprises two large
  density increases in white-light images. Comparison of white-light
  and in-situ observations shows that the flux-rope is embedded inside
  these two density increases. The evolution of the CME brightness in
  white-light images is discussed in terms of the kinematic evolution
  of the transient and its interaction with the ambient solar wind.

Title: The Structure of Streamer Blobs
Authors: Sheeley, N. R., Jr.; Lee, D. D. -H.; Casto, K. P.; Wang,
   Y. -M.; Rich, N. B.
Bibcode: 2009ApJ...694.1471S
Altcode:
  We have used Sun-Earth Connection Coronal and Heliospheric Investigation
  observations obtained from the STEREO A and B spacecraft to study
  complementary face-on and edge-on views of coronal streamers. The
  face-on views are analogous to what one might see looking down on a flat
  equatorial streamer belt at sunspot minimum, and show streamer blobs
  as diffuse arches gradually expanding outward from the Sun. With the
  passage of time, the legs of the arches fade, and the ejections appear
  as a series of azimuthal structures like ripples on a pond. The arched
  topology is similar to that obtained in face-on views of streamer
  disconnection events (including in/out pairs and streamer blowout
  mass ejections), and suggests that streamer blobs have the helical
  structure of magnetic flux ropes.

Title: Understanding the Geomagnetic Precursor of the Solar Cycle
Authors: Wang, Y. -M.; Sheeley, N. R.
Bibcode: 2009ApJ...694L..11W
Altcode:
  Geomagnetic activity late in the sunspot cycle has been used
  successfully to forecast the amplitude of the following cycle. This
  success is somewhat surprising, however, because the recurrent
  high-speed wind streams that trigger the activity are not proxies of
  the Sun's polar fields, whose strength is a critical factor in many
  solar dynamo models. Instead, recurrent geomagnetic activity signals
  increases in the Sun's equatorial dipole moment, which decays on the
  ~1-2 yr timescale of the surface meridional flow and does not survive
  into the next cycle. In accordance with the original empirical method
  of Ohl, we therefore argue that solar cycle predictions should be based
  on the minimum level of geomagnetic activity, which is determined by
  the Sun's axial dipole strength, not on the peak activity during the
  declining phase of the cycle. On physical grounds, we suggest that
  an even better indicator would be the total open flux (or strength of
  the radial interplanetary field component) at sunspot minimum, which
  in turn can be derived from the historical aa index by removing the
  contribution of the solar wind speed. This predictor yields a peak
  yearly sunspot number R <SUB>max</SUB> = 97 ± 25 for solar cycle 24.

Title: A synoptic view of solar transient evolution in the inner
    heliosphere using the Heliospheric Imagers on STEREO
Authors: Davies, J. A.; Harrison, R. A.; Rouillard, A. P.; Sheeley,
   N. R.; Perry, C. H.; Bewsher, D.; Davis, C. J.; Eyles, C. J.; Crothers,
   S. R.; Brown, D. S.
Bibcode: 2009GeoRL..36.2102D
Altcode:
  By exploiting data from the STEREO/heliospheric imagers (HI) we extend
  a well-established technique developed for coronal analysis by producing
  time-elongation plots that reveal the nature of solar transient activity
  over a far more extensive region of the heliosphere than previously
  possible from coronagraph images. Despite the simplicity of these plots,
  their power in demonstrating how the plethora of ascending coronal
  features observed near the Sun evolve as they move antisunward is
  obvious. The time-elongation profile of a transient tracked by HI can,
  moreover, be used to establish its angle out of the plane-of-the-sky an
  illustration of such analysis reveals coronal mass ejection material
  that can be clearly observed propagating out to distances beyond
  1AU. This work confirms the value of the time-elongation format in
  identifying/characterising transient activity in the inner heliosphere,
  whilst also validating the ability of HI to continuously monitor solar
  ejecta out to and beyond 1AU.

Title: Remote Sensing of the Slow Solar Wind
Authors: Sheeley, N. R.
Bibcode: 2008AGUFMSH43B..05S
Altcode:
  We are using SECCHI (Sun Earth Connection Coronal and Heliospheric
  Imager) observations from the STEREO (Solar Terrestrial Relations
  Observatory) spacecraft to construct elongation/time maps of material
  moving outward from about 2 solar radii to distances beyond the orbit
  of Earth. These maps span all position angles within the low-latitude
  fields of the Heliospheric Imagers and provide synoptic coverage of the
  motions observed since April 2007. These motions include the gradual
  acceleration of streamer blobs to solar wind speeds in the range
  300-400 km/s. They also include streamer detachments and eruptions,
  in which the inflating streamers stretch until they separate into
  collapsing loops and outgoing arches that reach terminal speeds in
  the range 300-500 km/s. During 2008, the two STEREO spacecraft have
  separated by 68 degrees, and are now providing complementary views of
  these ejecta. Recent observations show that some of the streamer blobs
  and ejections have the helical topology expected for magnetic flux
  ropes produced by field line reconnection in the corona and solar wind.

Title: On the Solar Origins of Open Magnetic Fields in the Heliosphere
Authors: Rust, David M.; Haggerty, Dennis K.; Georgoulis, Manolis K.;
   Sheeley, Neil R.; Wang, Yi-Ming; DeRosa, Marc L.; Schrijver, Carolus J.
Bibcode: 2008ApJ...687..635R
Altcode:
  A combination of heliospheric and solar data was used to identify open
  magnetic fields stretching from the lower corona to Earth orbit. 35
  near-relativistic electron beams detected at the ACE spacecraft
  "labeled" the heliospheric segments of the open fields. An X-ray
  flare occurred &lt;20 minutes before injection of the electrons
  in 25 events. These flares labeled the solar segment of the open
  fields. The flares occurred in western-hemisphere active regions (ARs)
  with coronal holes whose polarity agreed with the polarity of the
  beam-carrying interplanetary fields in 23 of the 25 events. We conclude
  that electron beams reach 1 AU from open AR fields adjacent to flare
  sites. The Wang &amp; Sheeley implementation of the potential-field
  source-surface model successfully identified the open fields in
  36% of cases. Success meant that the open fields reached the source
  surface within 3 heliographic deg of the interplanetary magnetic field
  connected to ACE at 1 AU. Inclusion of five near misses improves
  the success rate to 56%. The success rate for the Schrijver &amp;
  DeRosa PFSS implementation was 50%. Our results suggest that, even
  if the input magnetic data are updated frequently, the PFSS models
  succeed in only ~50% of cases to identify the coronal segment of open
  fields. Development of other techniques is in its infancy.

Title: A Century of Polar Faculae Variations
Authors: Sheeley, N. R., Jr.
Bibcode: 2008ApJ...680.1553S
Altcode:
  The numbers of faculae at the poles of the Sun have been estimated from
  white-light images obtained at the Mount Wilson Observatory during
  1985-2006 and combined with prior estimates extending back to 1906,
  when the observations began. The combined data show an 11 yr cyclic
  variation with faculae maxima occurring during sunspot minima in each
  of the past 10 sunspot cycles. Also, these numbers of polar faculae are
  well correlated with the line-of-sight component of the polar magnetic
  field measured at the Wilcox Solar Observatory since 1976. The numbers
  of polar faculae show a secular decrease since 1986, suggesting that
  the polar fields are now weaker than they have been during any cycle
  in the past century.

Title: A Century of Polar Faculae Variations
Authors: Sheeley, N. R.
Bibcode: 2008AGUSMSP23A..04S
Altcode:
  The numbers of faculae at the poles of the Sun have been estimated
  from white-light images obtained at the Mount Wilson Observatory
  during 1985-2006 and combined with prior estimates extending back
  to 1906 when the observations began. The combined data show an 11-yr
  cyclic variation with faculae maxima occurring during sunspot minima
  in each of the past 10 sunspot cycles. Also, these numbers of polar
  faculae are well correlated with the line-of-sight component of the
  polar magnetic field measured at the Wilcox Solar Observatory since
  1976. The numbers of polar faculae show a secular decrease since 1986,
  suggesting that the polar fields are now weaker than they have been
  during any cycle in the past century.

Title: Heliospheric Images of the Solar Wind at Earth
Authors: Sheeley, N. R., Jr.; Herbst, A. D.; Palatchi, C. A.; Wang,
   Y. -M.; Howard, R. A.; Moses, J. D.; Vourlidas, A.; Newmark, J. S.;
   Socker, D. G.; Plunkett, S. P.; Korendyke, C. M.; Burlaga, L. F.;
   Davila, J. M.; Thompson, W. T.; St. Cyr, O. C.; Harrison, R. A.;
   Davis, C. J.; Eyles, C. J.; Halain, J. P.; Wang, D.; Rich, N. B.;
   Battams, K.; Esfandiari, E.; Stenborg, G.
Bibcode: 2008ApJ...675..853S
Altcode:
  During relatively quiet solar conditions throughout the spring and
  summer of 2007, the SECCHI HI2 white-light telescope on the STEREO
  B solar-orbiting spacecraft observed a succession of wave fronts
  sweeping past Earth. We have compared these heliospheric images with
  in situ plasma and magnetic field measurements obtained by near-Earth
  spacecraft, and we have found a near perfect association between the
  occurrence of these waves and the arrival of density enhancements
  at the leading edges of high-speed solar wind streams. Virtually
  all of the strong corotating interaction regions are accompanied by
  large-scale waves, and the low-density regions between them lack such
  waves. Because the Sun was dominated by long-lived coronal holes and
  recurrent solar wind streams during this interval, there is little
  doubt that we have been observing the compression regions that are
  formed at low latitude as solar rotation causes the high-speed wind
  from coronal holes to run into lower speed wind ahead of it.

Title: SECCHI Observations of the Sun's Garden-Hose Density Spiral
Authors: Sheeley, N. R., Jr.; Herbst, A. D.; Palatchi, C. A.; Wang,
   Y. -M.; Howard, R. A.; Moses, J. D.; Vourlidas, A.; Newmark, J. S.;
   Socker, D. G.; Plunkett, S. P.; Korendyke, C. M.; Burlaga, L. F.;
   Davila, J. M.; Thompson, W. T.; St. Cyr, O. C.; Harrison, R. A.;
   Davis, C. J.; Eyles, C. J.; Halain, J. P.; Wang, D.; Rich, N. B.;
   Battams, K.; Esfandiari, E.; Stenborg, G.
Bibcode: 2008ApJ...674L.109S
Altcode:
  The SECCHI HI2 white-light imagers on the STEREO A and B spacecraft
  show systematically different proper motions of material moving outward
  from the Sun in front of high-speed solar wind streams from coronal
  holes. As a group of ejections enters the eastern (A) field of view,
  the elements at the rear of the group appear to overrun the elements
  at the front. (This is a projection effect and does not mean that the
  different elements actually merge.) The opposite is true in the western
  (B) field; the elements at the front of the group appear to run away
  from the elements at the rear. Elongation/time maps show this effect
  as a characteristic grouping of the tracks of motion into convergent
  patterns in the east and divergent patterns in the west, consistent
  with ejections from a single longitude on the rotating Sun. Evidently,
  we are observing segments of the "garden-hose" spiral made visible
  when fast wind from a low-latitude coronal hole compresses blobs of
  streamer material being shed at the leading edge of the hole.

Title: Global structure and dynamics of large-scale fluctuations in
the solar wind: Voyager 2 observations during 2005 and 2006
Authors: Burlaga, L. F.; Ness, N. F.; Acũna, M. H.; Wang, Y. -M.;
   Sheeley, N. R.; Wang, C.; Richardson, J. D.
Bibcode: 2008JGRA..113.2104B
Altcode:
  The Voyager 2 (V2) observations of daily averages of the solar
  wind during 2005 and 2006 from 75.3 AU to 81.6 AU between ~25.7°S
  and 27.1°S show both a step-like trend in the speed V(t) and
  ``large-scale fluctuations'' of the magnetic field strength B, speed
  V, density N and temperature T. The distribution functions of B,
  N, and NV<SUP>2</SUP> observed by V2 are lognormal and that of V
  is approximately Gaussian. We introduce a method for specifying
  the boundary conditions at all latitudes (except near the poles)
  on a Sun-centered surface of radius of 1 AU, based on solar magnetic
  field observations. This paper uses only the boundary conditions at
  the latitude of V2 and a 1-D time-dependent MHD model to calculate
  the radial evolution of the large-scale fluctuations of B(t), V(t)
  and N(t) at distances between 1 and 90 AU. This model explains the
  V2 observations of a lognormal distribution of B and the Gaussian
  distribution of V, but not the observed lognormal distributions of
  N and NV<SUP>2</SUP>. The lognormal distribution of B observed by V2
  was produced primarily by dynamical processes beyond 1 AU.

Title: Limits to the Radiative Asymmetry of the Quiet Solar Disk
Authors: Livingston, W.; Sheeley, N. R., Jr.
Bibcode: 2008ApJ...672.1228L
Altcode:
  Precise data on the uniformity of photospheric radiation over the solar
  disk seems not to exist. Such information is necessary to separate
  the radiative behavior of the quiet basal atmosphere from the active
  (magnetic) atmosphere. Is the latter the sole source of known irradiance
  variation? How uniform can a solar-like stellar disk be? To obtain this
  information we have made monochromatic scans along the central meridian
  of the quiet Sun using single element detectors which do not require
  flat fielding. The scans were in continua and in selected Fraunhofer
  lines ranging from 3134 to 46880 Å the observational epoch was near
  solar minimum: 2006 October to 2007 February. The meridian was chosen
  to avoid rotational Doppler shifts. We extract the asymmetry between
  the north and south hemispheres and present it as our main product. In
  the near-infrared and visible continuum, averaging over granulation and
  avoiding sunspots, we found that such asymmetry was as low as 0.05%
  (at 34168 Å on 2007 February 8). In the violet and ultraviolet this
  asymmetry typically increases to 1%. Asymmetry is larger in the cores
  of the medium strong photospheric and chromospheric lines, which refer
  to higher levels in the atmosphere, and may reach 15%. The contrast of
  faculae increases in the blue (and with improved spatial resolution or
  seeing), and is the probable source for the measured asymmetries. We
  also find that line core scans are in general flatter than continuum
  scans.

Title: A Streamer Ejection with Reconnection Close to the Sun
Authors: Sheeley, N. R., Jr.; Warren, H. P.; Wang, Y. -M.
Bibcode: 2007ApJ...671..926S
Altcode:
  We previously described coronal events that expand gradually outward
  over an interval of 1-2 days and then suddenly tear apart in the
  coronagraph's 2-6 R<SUB>solar</SUB> field of view to form an outgoing
  flux rope and an inward system of collapsing loops. Now, we combine
  LASCO white-light images of the outer corona with spectrally resolved
  EIT images of the inner corona to describe a similar event for which the
  separation occurs closer to the Sun. The evolution of this 2006 July
  1-2 event had four phases: (1) an expansion phase in which magnetic
  loops rise slowly upward and increase the amount of open flux in the
  adjacent polar coronal hole and in the low-latitude hole of opposite
  polarity; (2) a stretching phase in which the legs of the rising
  loops pinch together to form a current sheet; (3) a transition phase
  in which field line reconnection produces an outgoing flux rope and a
  hot cusp of new loops; and (4) an end phase in which the reconnected
  loops become visible at lower temperatures, and the outgoing flux rope
  plows through the slow material ahead of it to form a traveling bow
  wave. During this time, the photospheric field was relatively weak and
  unchanging, as if the eruption had a nonmagnetic origin. We suppose
  that coronal heating gradually overpowers magnetic tension and causes
  the streamer to separate into a system of collapsing loops and a flux
  rope that is carried outward in the solar wind.

Title: Secchi Observations of Mass Flows in the Inner Heliosphere
Authors: Sheeley, N. R.; Herbst, A. D.; Palatchi, C. A.; Wang, Y.
Bibcode: 2007AGUFMSH42A..01S
Altcode:
  We use SECCHI (Sun Earth Connection Coronal and Heliospheric
  Investigation) observations to construct "height/time" maps of material
  flows in the heliosphere from the Sun to elongation angles beyond
  90 degrees. Close to the Sun, we see accelerating tracks of ejecta
  (like streamer blobs) close to the sky plane. Farther from the Sun,
  we see groups of parallel tracks, some near the sky plane and some
  out of the plane. At the greatest elongations, we see a collection of
  non-parallel tracks, some merging and some crossing, and mainly from
  directions well out of the sky plane. These maps and their associated
  time- lapse movies are providing a new view of mass flows and their
  interactions in the inner heliosphere.

Title: The Solar Eclipse of 2006 and the Origin of Raylike Features
    in the White-Light Corona
Authors: Wang, Y. -M.; Biersteker, J. B.; Sheeley, N. R., Jr.;
   Koutchmy, S.; Mouette, J.; Druckmüller, M.
Bibcode: 2007ApJ...660..882W
Altcode:
  Solar eclipse observations have long suggested that the white-light
  corona is permeated by long fine rays. By comparing photographs of
  the 2006 March 29 total eclipse with current-free extrapolations of
  photospheric field measurements and with images from the Solar and
  Heliospheric Observatory (SOHO), we deduce that the bulk of these
  linear features fall into three categories: (1) polar and low-latitude
  plumes that overlie small magnetic bipoles inside coronal holes,
  (2) helmet streamer rays that overlie large loop arcades and separate
  coronal holes of opposite polarity, and (3) ``pseudostreamer'' rays
  that overlie twin loop arcades and separate coronal holes of the
  same polarity. The helmet streamer rays extend outward to form the
  plasma sheet component of the slow solar wind, while the plumes and
  pseudostreamers contribute to the fast solar wind. In all three cases,
  the rays are formed by magnetic reconnection between closed coronal
  loops and adjacent open field lines. Although seemingly ubiquitous
  when seen projected against the sky plane, the rays are in fact rooted
  inside or along the boundaries of coronal holes.

Title: Limits To The Radiative Asymmetry Of The Quiet Solar Disk
Authors: Livingston, W. C.; Sheeley, N. R.
Bibcode: 2007AAS...210.2503L
Altcode: 2007BAAS...39..131L
  Precise data on the uniformity of photospheric radiation over the solar
  disk seems not to exist. Such may be needed for the future detection
  of planets crossing solar-like stellar disks, for example. To obtain
  this information we have made monochromatic scans along the central
  meridian of the quiet Sun using single element detectors which do not
  require ’flat fielding’. The scans were in continua and selected
  Fraunhofer lines ranging from 3129 to 46880 A; the observational epoch
  was near solar minimum: Oct 2006 to Feb 2007. The meridian was chosen
  to avoid rotational doppler shifts. We extract the asymmetry between
  the N and S hemispheres and this is our main product. In the near IR
  and visible continuum, averaging over granulation and discounting
  sunspots, such asymmetry is as low as 0.01%; 0.005% at 34168 A on
  8 Feb 2007. In the violet and UV this increases to 1%. In the cores
  of medium strength photospheric lines and in chromospheric lines the
  asymmetry is up to 15%. Faculae are the probable source of our measured
  quiet disk asymmetries, and the continuum at 34168 A is favorable for
  this reason. Line core scans are in general flatter than continuum
  scans because they sample thinner, higher layers of the atmosphere,
  where the temperature gradient is less.

Title: Coronal Pseudostreamers
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.; Rich, N. B.
Bibcode: 2007ApJ...658.1340W
Altcode:
  In a recent study of the 2006 solar eclipse, we noted that there are
  two kinds of coronal streamers: ``helmet streamers,'' which separate
  coronal holes of opposite magnetic polarity, and ``pseudostreamers,''
  which overlie twin loop arcades and separate holes of the same
  polarity. It is well known that the heliospheric plasma and current
  sheets represent the outward extension of helmet streamers. Using
  white-light data from the Large Angle and Spectrometric Coronagraph
  (LASCO), we here show that pseudostreamers likewise have plasma sheet
  extensions, across which the polarity does not reverse; these multiple
  sheets contribute significantly to the brightness of the K corona,
  although their internal densities tend to be lower than those in
  the heliospheric plasma sheet. We use current-free extrapolations of
  photospheric field measurements to simulate the observed brightness
  patterns in the outer corona, including the contributions of both
  helmet streamer and pseudostreamer plasma sheets. Running-difference
  images show that pseudostreamers are relatively quiescent, resembling
  large-scale plumes; preliminary analysis suggests flow speeds as
  high as 200 km s<SUP>-1</SUP> at heliocentric distances of only ~3
  R<SUB>solar</SUB>, supporting the prediction (based on their low
  flux tube divergence rates) that pseudostreamers are sources of fast
  solar wind.

Title: In/Out Pairs and the Detachment of Coronal Streamers
Authors: Sheeley, N. R., Jr.; Wang, Y. -M.
Bibcode: 2007ApJ...655.1142S
Altcode:
  We previously described coronal events that originate in the 2-6
  R<SUB>solar</SUB> field of view of the LASCO white-light coronagraph
  and involve the simultaneous ejection of material inward toward the
  Sun and outward away from it. Now, in a study of more than 160 in/out
  pairs, we have found that these features are density enhancements at
  the leading and trailing edges of depletions that occur when slowly
  rising coronal structures separate from the Sun. The outward component
  is shaped like a large arch with both ends attached to the Sun, and the
  inward component is often resolved into loops. We also found about 60
  additional events in which the outward components began near the edge of
  the occulting disk and inward components were not visible, as if these
  events were in/out pairs that originated below the 2 R<SUB>solar</SUB>
  radius of the occulting disk. We conclude that in/out pairs belong to a
  broad class of streamer detachments, which include ``streamer blowout''
  coronal mass ejections, and we suppose that all of these events occur
  when rising magnetic loops reconnect to produce an outgoing helical
  flux rope and an ingoing arcade of collapsing loops.

Title: Sources of the Solar Wind at Ulysses during 1990-2006
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 2006ApJ...653..708W
Altcode:
  The Ulysses spacecraft is now well into its third polar orbit around
  the Sun. Using stackplot displays, we summarize the wind speeds and
  interplanetary sector polarities recorded by Ulysses since its launch
  in 1990 and relate the observed patterns to the global evolution of
  open magnetic regions (coronal holes) over the solar cycle. We verify
  that the wind speeds are inversely correlated with the rate of flux-tube
  divergence in the corona, as derived from a current-free extrapolation
  of the measured photospheric field. We identify the source of each of
  the long-lived, high-speed streams encountered by Ulysses and discuss
  their formation, evolution, and rotational properties.

Title: Observations of Flux Rope Formation in the Outer Corona
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 2006ApJ...650.1172W
Altcode:
  In previous studies employing the Large Angle and Spectrometric
  Coronagraph (LASCO), we identified a class of white-light ejections
  that separate into incoming and outgoing components at distances of
  ~3-5 R<SUB>solar</SUB> from Sun center. These events, of which up to
  several per month are observed during high solar activity, are generally
  preceded by a gradual outward expansion of faint loops over a period
  of a day or more. The expansion terminates when the streamer material,
  in the form of an elongated stalk or a sheetlike structure, suddenly
  tears apart. The collapsing material is sometimes recognizable as a
  collection of loops, while the ejected component is usually poorly
  resolved. Here we describe a streamer detachment observed on 2005
  December 11, in which the outgoing component can be clearly identified
  as a cylindrical flux rope with its ends anchored in the Sun. Based
  on simple three-dimensional white-light reconstructions, we conclude
  that in/out pairs in general represent the pinching off of streamer
  loop arcades to form flux ropes, as seen from different viewing angles.

Title: Role of the Sun's Nonaxisymmetric Open Flux in Cosmic-Ray
    Modulation
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.; Rouillard, A. P.
Bibcode: 2006ApJ...644..638W
Altcode:
  We reexamine the empirical relationship between the Sun's open magnetic
  flux and the cosmic-ray (CR) intensity over the solar cycle. The
  single parameter that correlates best with the inverted CR rate is
  found to be the nonaxisymmetric or longitudinally varying component
  of the total open flux, rather than the sunspot number or the rate
  of coronal mass ejections (CMEs). The nonaxisymmetric open flux in
  turn tracks the evolution of the Sun's equatorial dipole component,
  which is a function of both the strength and the longitudinal
  distribution of sunspot activity. Year-long peaks in the equatorial
  dipole strength coincide with steplike decreases in the CR intensity
  and with the formation of global merged interaction regions (GMIRs)
  in the outer heliosphere. During these periods, nonaxisymmetric open
  flux (in the form of low-latitude coronal holes) is created through the
  organized emergence of large active regions, resulting in the global
  injection of magnetic energy into the heliosphere. At the same time,
  strengthenings of the equatorial dipole are generally accompanied
  by large increases in the number of fast CMEs. Rotationally induced,
  compressional interactions between the nonaxisymmetric open flux, fast
  CMEs, and high-speed streams then give rise to outward-propagating
  diffusive barriers that extend over all longitudes and to a latitude
  (&gt;~45°) again determined by the equatorial dipole strength.

Title: Solar physics: Back to the next solar cycle
Authors: Wang, Y. -M.; Sheeley, N. R.
Bibcode: 2006NatPh...2..367W
Altcode:
  Many solar physicists expect the peak sunspot activity during the
  next solar cycle to be at its weakest in almost a century. A recent
  prediction to the contrary could turn this prevailing wisdom on
  its head.

Title: Probing Solar Open Magnetic Fields With Near-relativistic
    Electron Beams.
Authors: Haggerty, Dennis K.; Rust, D.; Sheeley, N. R.; Wang, Y.
Bibcode: 2006SPD....37.1102H
Altcode: 2006BAAS...38R.238H
  To achieve better understanding of our Sun-Earth environment,
  NASA's Living with a Star (LWS) program addresses question that
  cut across discipline boundaries. We present preliminary results on
  probing solar open magnetic fields with near-relativistic electron
  beams. This effort is directed at the major question: What determines
  the topology and evolution of the magnetic fields that stretch from the
  surface of the Sun to the outer boundary of the heliosphere? During
  nine years of operation, nearly an entire solar cycle, the ACE/EPAM
  instrument has measured well over 600 near-relativistic electron
  events. Approximately 30% of these electron events are impulsive
  with beam-like anisotropies and are predominantly from flares on the
  western hemisphere. Near-relativistic electrons are accelerated in the
  low corona and are released onto open coronal field lines, where they
  propagate nearly scatter-free out to 1 AU. Near-relativistic electrons
  are ideal probes of coronal open field lines because the transit time
  to 1 AU is 10 minutes as compared to lower energy ions that spend more
  time in the interplanetary medium and are therefore much more subject
  to transport processes. In this work we use observations of electrons
  from 1 AU, observations of various electromagnetic emissions associated
  with electron acceleration at the Sun, and observations and models
  of open magnetic field lines at the Sun to pinpoint the location of
  electron acceleration.

Title: Carrington Maps of the Upper Photosphere
Authors: Sheeley, N. R., Jr.; Warren, H. P.
Bibcode: 2006ApJ...641..611S
Altcode:
  We have used images of the Sun's disk, obtained in the 6767 Å
  continuum with the Michelson Doppler Interferometer (MDI) on the
  Solar and Heliospheric Observatory (SOHO), to make Carrington
  maps of the upper photosphere during the years 1996-2005. Each map
  is constructed from observations near the limb where the continuum
  radiation originates relatively high in the photosphere and faculae have
  their greatest visibility. Consequently, the Carrington maps resemble
  spectroheliograms in temperature-sensitive photospheric lines and show
  the global distribution of faculae and all but the smallest sunspots
  (which are obscured by overlying faculae). A time-lapse sequence of the
  combined east-limb and west-limb maps shows the emergence of active
  regions and the evolution of large-scale patterns of faculae with an
  average temporal resolution of 14 days during the sunspot cycle. Also,
  a longitudinally averaged butterfly diagram of these maps shows that in
  each hemisphere there is a facula-free zone separating the old-cycle
  polar field from trailing-polarity flux that is migrating poleward
  from the sunspot belts. These facula-free zones coincide with the
  neutral zones of the axisymmetric component of photospheric magnetic
  field and their arrival at the poles in 2001 marks the reversal of the
  polar fields. We think that this mapmaking technique can be applied
  to white-light images obtained daily at the Mount Wilson Observatory
  since 1905 and that the resulting Carrington maps will provide details
  about the polar-field reversal process during past sunspot cycles when
  high-quality magnetograms were unavailable.

Title: Multi-Wavelength Observations of CMEs and Associated Phenomena.
    Report of Working Group F
Authors: Pick, M.; Forbes, T. G.; Mann, G.; Cane, H. V.; Chen, J.;
   Ciaravella, A.; Cremades, H.; Howard, R. A.; Hudson, H. S.; Klassen,
   A.; Klein, K. L.; Lee, M. A.; Linker, J. A.; Maia, D.; Mikic,
   Z.; Raymond, J. C.; Reiner, M. J.; Simnett, G. M.; Srivastava, N.;
   Tripathi, D.; Vainio, R.; Vourlidas, A.; Zhang, J.; Zurbuchen, T. H.;
   Sheeley, N. R.; Marqué, C.
Bibcode: 2006SSRv..123..341P
Altcode: 2006SSRv..tmp...60P
  This chapter reviews how our knowledge of CMEs and CME-associated
  phenomena has been improved, since the launch of the SOHO mission,
  thanks to multi-wavelength analysis. The combination of data obtained
  from space-based experiments and ground based instruments allows us
  to follow the space-time development of an event from the bottom of
  the corona to large distances in the interplanetary medium. Since CMEs
  originate in the low solar corona, understanding the physical processes
  that generate them is strongly dependant on coordinated multi-wavelength
  observations. CMEs display a large diversity in morphology and kinematic
  properties, but there is presently no statistical evidence that those
  properties may serve to group them into different classes. When a CME
  takes place, the coronal magnetic field undergoes restructuring. Much
  of the current research is focused on understanding how the corona
  sustains the stresses that allow the magnetic energy to build up and
  how, later on, this magnetic energy is released during eruptive flares
  and CMEs. Multi-wavelength observations have confirmed that reconnection
  plays a key role during the development of CMEs. Frequently, CMEs
  display a rather simple shape, exhibiting a well known three-part
  structure (bright leading edge, dark cavity and bright knot). These
  types of events have led to the proposal of the ‘`standard model’'
  of the development of a CME, a model which predicts the formation
  of current sheets. A few recent coronal observations provide some
  evidence for such sheets. Other more complex events correspond to
  multiple eruptions taking place on a time scale much shorter than the
  cadence of coronagraph instruments. They are often associated with
  large-scale dimming and coronal waves. The exact nature of these waves
  and the physical link between these different manifestations are not
  yet elucidated. We also discuss what kind of shocks are produced during
  a flare or a CME. Several questions remain unanswered. What is the
  nature of the shocks in the corona (blast-wave or piston-driven?) How
  they are related to Moreton waves seen in Hα? How they are related
  to interplanetary shocks? The last section discusses the origin of
  energetic electrons detected in the corona and in the interplanetary
  medium. “Complex type III-like events,”which are detected at
  hectometric wavelengths, high in the corona, and are associated with
  CMEs, appear to originate from electrons that have been accelerated
  lower in the corona and not at the bow shock of CMEs. Similarly,
  impulsive energetic electrons observed in the interplanetary medium
  are not the exclusive result of electron acceleration at the bow shocks
  of CMEs; rather they have a coronal origin.

Title: Multi-Wavelength Observations of CMEs and Associated Phenomena
Authors: Pick, M.; Forbes, T. G.; Mann, G.; Cane, H. V.; Chen, J.;
   Ciaravella, A.; Cremades, H.; Howard, R. A.; Hudson, H. S.; Klassen,
   A.; Klein, K. L.; Lee, M. A.; Linker, J. A.; Maia, D.; Mikic,
   Z.; Raymond, J. C.; Reiner, M. J.; Simnett, G. M.; Srivastava, N.;
   Tripathi, D.; Vainio, R.; Vourlidas, A.; Zhang, J.; Zurbuchen, T. H.;
   Sheeley, N. R.; Marqué, C.
Bibcode: 2006cme..book..341P
Altcode:
  This chapter reviews how our knowledge of CMEs and CME-associated
  phenomena has been improved, since the launch of the SOHO mission,
  thanks to multi-wavelength analysis. The combination of data obtained
  from space-based experiments and ground based instruments allows us
  to follow the space-time development of an event from the bottom of
  the corona to large distances in the interplanetary medium. Since
  CMEs originate in the low solar corona, understanding the physical
  processes that generate them is strongly dependant on coordinated
  multi-wavelength observations. CMEs display a large diversity in
  morphology and kinematic properties, but there is presently no
  statistical evidence that those properties may serve to group them
  into different classes. When a CME takes place, the coronal magnetic
  field undergoes restructuring. Much of the current research is focused
  on understanding how the corona sustains the stresses that allow the
  magnetic energy to build up and how, later on, this magnetic energy is
  released during eruptive flares and CMEs. Multiwavelength observations
  have confirmed that reconnection plays a key role during the development
  of CMEs. Frequently, CMEs display a rather simple shape, exhibiting a
  well known three-part structure (bright leading edge, dark cavity and
  bright knot). These types of events have led to the proposal of the
  "standard model" of the development of a CME, a model which predicts
  the formation current sheets. A few recent coronal observations provide
  some evidence for such sheets. Other more complex events correspond
  to multiple eruptions taking place on a time scale much shorter than
  the cadence of coronagraph instruments. They are often associated with
  large-scale dimming and coronal waves. The exact nature of these waves
  and the physical link between these different manifestations are not
  yet elucidated. We also discuss what kind of shocks are produced during
  a flare or a CME. Several questions remain unanswered. What is the
  nature of the shocks in the corona (blast-wave or piston-driven?) How
  they are related to Moreton waves seen in Hα? How they are related
  to interplanetary shocks? The last section discusses the origin of
  energetic electrons detected in the corona and in the interplanetary
  medium. "Complex type III-like events," which are detected at
  hectometric wavelengths, high in the corona, and are associated with
  CMEs, appear to originate from electrons that have been accelerated
  lower in the corona and not at the bow shock of CMEs. Similarly,
  impulsive energetic electrons observed in the interplanetary medium
  are not the exclusive result of electron acceleration at the bow shocks
  of CMEs; rather they have a coronal origin.

Title: Surface Evolution of the Sun's Magnetic Field: A Historical
    Review of the Flux-Transport Mechanism
Authors: Sheeley, Neil R., Jr.
Bibcode: 2005LRSP....2....5S
Altcode:
  This paper reviews our attempts to understand the transport of
  magnetic flux on the Sun from the Babcock and Leighton models to
  the recent revisions that are being used to simulate the field over
  many sunspot cycles. In these models, the flux originates in sunspot
  groups and spreads outward on the surface via supergranular diffusion;
  the expanding patterns become sheared by differential rotation, and
  the remnants are carried poleward by meridional flow. The net result
  of all of the flux eruptions during a sunspot cycle is to replace the
  initial polar fields with new fields of opposite polarity. A central
  issue in this process is the role of meridional flow, whose relatively
  low speed is near the limit of detection with Doppler techniques. A
  compelling feature of Leighton's original model was that it reversed the
  polar fields without the need for meridional flow. Now, we think that
  meridional flow is central to the reversal and to the dynamo itself.

Title: The Transport of Photospheric Magnetic Flux (Invited)
Authors: Sheeley, N. R., Jr.
Bibcode: 2005ESASP.592..233S
Altcode: 2005soho...16E..35S; 2005ESASP.592E..35S
  No abstract at ADS

Title: Modeling the Sun's Magnetic Field and Irradiance since 1713
Authors: Wang, Y. -M.; Lean, J. L.; Sheeley, N. R., Jr.
Bibcode: 2005ApJ...625..522W
Altcode:
  We use a flux transport model to simulate the evolution of the
  Sun's total and open magnetic flux over the last 26 solar cycles
  (1713-1996). Polar field reversals are maintained by varying the
  meridional flow speed between 11 and 20 m s<SUP>-1</SUP>, with the
  poleward-directed surface flow being slower during low-amplitude
  cycles. If the strengths of the active regions are fixed but their
  numbers are taken to be proportional to the cycle amplitude, the
  open flux is found to scale approximately as the square root of the
  cycle amplitude. However, the scaling becomes linear if the number of
  active regions per cycle is fixed but their average strength is taken
  to be proportional to the cycle amplitude. Even with the inclusion
  of a secularly varying ephemeral region background, the increase in
  the total photospheric flux between the Maunder minimum and the end of
  solar cycle 21 is at most ~one-third of its minimum-to-maximum variation
  during the latter cycle. The simulations are compared with geomagnetic
  activity and cosmogenic isotope records and are used to derive a
  new reconstruction of total solar irradiance (TSI). The increase in
  cycle-averaged TSI since the Maunder minimum is estimated to be ~1 W
  m<SUP>-2</SUP>. Because the diffusive decay rate accelerates as the
  average spacing between active regions decreases, the photospheric
  magnetic flux and facular brightness grow more slowly than the sunspot
  number and TSI saturates during the highest amplitude cycles.

Title: Solar Subsurface Flows of Active Region AR~0696
Authors: Komm, R.; Howe, R.; Donaldson Hanna, K.; Hill, F.; Sheeley, N.
Bibcode: 2005AGUSMSP24A..02K
Altcode:
  We use a ring-diagram analysis to determine the subsurface flows in
  the upper 16~Mm of the convection zone from high-resolution Global
  Oscillation Network Group (GONG) data obtained during the first two
  weeks of November 2004. The active region AR~0696 emerges near the
  eastern limb and moves across the disk during this time period. The
  region produced several terrestrially effective flares and halo
  CMEs during its transit across the disk. During its disk passage,
  AR~0696 is the only large active region in the northern hemisphere
  and almost the only flare producing region on the sun. This makes it a
  good candidate for investigating the relation between active regions,
  their flare activity, and associated subsurface flows. We will present
  the latest results. This work was supported by NASA grant NAG 5-11703.

Title: Global Structure of the Out-of-ecliptic Solar Wind
Authors: Whang, Y.; Wang, Y.; Sheeley, N.; Burlaga, L.
Bibcode: 2005AGUSMSH13A..03W
Altcode:
  We use the observed photospheric field maps and the wind speed
  observed from Ulysses to study the out-of-ecliptic solar wind. The
  model calculates the wind speed from the rate of magnetic flux-tube
  expansion factor using a conversion function that is determined by
  least-squares fit of all currently available data from Ulysses. Using
  the best-fit conversion function we investigate the global solar
  wind at all latitudes, from 90Âº south to 90Âº north, covering a
  36-year period from 1968 through 2003. The results complement and expand
  upon earlier studies conducted with IPS and other in situ spacecraft
  observations. The rotationally averaged wind speed is a function of
  two parameters: the heliolatitude and the phase of the solar cycle. The
  out-of-ecliptic solar wind has a recurrent stable structure, the average
  wind speed varies like a sine square of latitude profile spanning more
  than 5 years during the declining phase and solar minimum in each solar
  cycle. Near solar maximum the structure of the out-of-ecliptic solar
  wind is in a transient state lasting 2 to 3 years when the stable
  structure breaks down during the disappearance and reappearance of
  the polar coronal holes. We also report the Ulysses observations of
  the stable and transient structure.

Title: Global structure of the out-of-ecliptic solar wind
Authors: Whang, Y. C.; Wang, Y. -M.; Sheeley, N. R.; Burlaga, L. F.
Bibcode: 2005JGRA..110.3103W
Altcode: 2005JGRA..11003103W
  We use the observed photospheric field maps and the wind speed observed
  from Ulysses to study the out-of-ecliptic solar wind. The model
  calculates the wind speed from the rate of magnetic flux tube expansion
  factors using a conversion function that is determined by least squares
  fit of all currently available data from Ulysses. Using the best fit
  conversion function, we investigate the global solar wind covering
  a 36-year period from 1968 through 2003. The results complement and
  expand upon earlier studies conducted with interplanetary scintillation
  and other in situ spacecraft observations. The rotationally averaged
  wind speed is a function of two parameters: the heliolatitude and the
  phase of the solar cycle. The out-of-ecliptic solar wind has a recurrent
  stable structure, and the average wind speed varies like a sine square
  of latitude profile spanning more than 5 years during the declining
  phase and solar minimum in each solar cycle. Ulysses has observed
  this stable structure in its first polar orbit in 1992-1997. Near
  solar maximum the structure of the out-of-ecliptic solar wind is in a
  transient state lasting 2-3 years when the stable structure breaks down
  during the disappearance and reappearance of the polar coronal holes.

Title: The Origin of Postflare Loops
Authors: Sheeley, N. R., Jr.; Warren, H. P.; Wang, Y. -M.
Bibcode: 2004ApJ...616.1224S
Altcode:
  We apply a tracking technique, previously developed to study motions
  in the outer corona by Sheeley, Walters, Wang, and Howard, to 195 Å
  filtergrams obtained with the Transition Region and Coronal Explorer
  (TRACE) satellite and obtain height-time maps of the motions in the
  hot (10-20 MK) plasma clouds above postflare loop systems. These
  maps indicate the following two main characteristics. (1) Within the
  plasma cloud, the motions are downward at speeds of approximately 4
  km s<SUP>-1</SUP>. The cloud itself grows with time, its upper layers
  being replenished by the arrival and deceleration of fast inflows and
  its lower layers disappearing when they cool to form the tops of new
  postflare loops. (2) Early in these events, the inward motions are
  turbulent, showing a variety of dark elongated features resembling
  ``tadpoles'' and some bright features. Later, the inflows are visible
  as dark collapsing loops, changing from initially cusp-shaped features
  to rounder loops as they move inward. Their speeds initially lie in the
  range 100-600 km s<SUP>-1</SUP> but decrease to 4 km s<SUP>-1</SUP>
  in about 3 minutes, corresponding to an average deceleration ~1500 m
  s<SUP>-2</SUP>. Combining these observations with similar observations
  obtained at reconnection sites in the outer corona by the Large Angle
  Spectrometric Coronagraph (LASCO), we conclude that postflare loops are
  the end result of the formation, filling, deceleration, and cooling
  of magnetic loops produced by the reconnection of field lines blown
  open in the flare. The formation of collapsing loops occurs in the
  dark tadpoles; the filling of these initially dark loops occurs via
  chromospheric evaporation, which also contributes to the deceleration
  of the loops; and the radiative cooling ultimately resolves the loops
  into sharply defined structures.

Title: Footpoint Switching and the Evolution of Coronal Holes
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 2004ApJ...612.1196W
Altcode:
  We discuss the role of footpoint exchanges between open and closed
  magnetic field lines (also known as ``interchange reconnection'')
  in the formation and rotational evolution of coronal holes. Such
  exchanges cause open flux to jump from one location to another when
  active regions emerge; they also act to untie the rotation of coronal
  holes from that of the underlying plasma. We introduce a quantitative
  measure of the footpoint exchange rate and apply it to a variety of
  idealized configurations. During the formation of coronal holes,
  footpoint switching dominates over the creation of new open flux
  if the background (or polar) field is strong compared to that of
  the emerging active region, so the latter acts to change mainly the
  direction rather than the magnitude of the Sun's dipole vector. The
  principal role of footpoint exchanges is to counteract the subsequent
  rotational shearing of the holes; this result is accomplished by means
  of continual sideways displacements of open and closed field lines along
  the hole boundaries. Because the timescale for rotational shearing
  (~3 months) is less than that for the decay of the Sun's large-scale
  nonaxisymmetric field (~1 yr), interchange reconnection is expected
  on average to dominate over the closing down of flux throughout the
  solar cycle.

Title: The termination shock near 35° latitude
Authors: Whang, Y. C.; Burlaga, L. F.; Wang, Y. -M.; Sheeley, N. R.
Bibcode: 2004GeoRL..31.3805W
Altcode: 2004GeoRL..3103805W
  The termination shock moves outwards and inwards over timescales of a
  solar cycle in response to the variations in the average solar wind
  speed. The amplitude is greater than 50 AU near 35° latitude; the
  maximum (minimum) distance occurs during the rising (declining) phase
  of the solar cycle. Shock parameters are distinctly different when
  the shock moves outwards or inwards. During the period of high-speed
  (low-speed) solar wind, the shock moves outward (inward) and the shock
  is weaker (stronger). This study assumes that the first crossing of
  Voyager 1 with the termination shock occurred at 85.5 AU on 2002.6. If
  Voyager 1 did cross the shock in 2002.6, the spacecraft would likely
  cross the shock at least two more times before 2010, but no second
  crossing would occur close to 2003.1. If Voyager 1 did not cross the
  shock in mid-2002, it might still do so before 2005.

Title: The termination shock near 35 degrees latitude
Authors: Whang, Y. C.; Burlaga, L. F.; Wang, Y.; Sheeley, N. R.
Bibcode: 2003AGUFMSH11C1115W
Altcode:
  The paper calculates the solar cycle variation of the termination
  shock near 35 degrees latitude. The solution assumes that Voyager 1
  crossed the termination shock at 85.5 AU on 2002.6. At mid latitudes,
  the termination shock is an oblique shock; the shock location is
  unambiguously solar cycle dependent with amplitude greater than 50
  AU. The maximum (minimum) distance occurs during the rising (declining)
  phase of the solar cycle. During the period of high-speed (low-speed)
  solar wind, the termination shock moves outward (inward) and the
  shock is weaker (stronger). The calculation provides the shock speed,
  the shock strength, the preshock and postshock solar wind speed, and
  the flow speed in the shock frame of reference. The shock parameters
  are distinctly different depending on whether the shock moves outward
  or inward. If Voyager 1 did cross the termination shock in 2002.6, it
  would likely cross the shock coming back to the solar wind near 98 AU
  in 2006 during the next outward motion of the termination shock, while
  in 2010 the spacecraft would cross the termination shock back into the
  heliosheath near 113 AU during the inward motion of the termination
  shock near the maximum of Cycle 24. If Voyager 1 did not cross the
  termination shock in mid-2002, it might still do so before 2005.

Title: Relating Interplanetary Helium Variation to Coronal Magnetic
    Fields and Solar Wind Formation
Authors: Kasper, J. C.; Lazarus, A. J.; Steinberg, J. T.; Riley, P.;
   Sheeley, N.; Wang, Y.
Bibcode: 2003AGUFMSH11D1136K
Altcode:
  We have recently identified two new features in the variation of the
  relative abundance of helium in the solar wind relative to hydrogen
  as observed by the Wind spacecraft. First, the He/H ratio is a
  linear function of speed for solar wind speeds ranging from 250-550
  km/s. This signal is most evident during the previous solar minimum
  from 1995 through 1997. Secondly, during that same quiet interval we
  have identified a six-month periodic modulation of the He/H ratio which
  can be seen at all solar wind speeds. This modulation is in phase with
  the orbit of the Earth about the Sun, and maxima in He/H occur at the
  times when Earth is most distant from the heliographic equator. As
  we shall demonstrate, these effects are partly in agreement with
  theoretical models of the magnetic topology of the corona and of the
  formation of the solar wind. However, these features present challenges
  to the currently accepted paradigm of solar wind, with helium-poor wind
  emerging from coronal streamers and fast, helium-rich wind emerging from
  coronal holes. The abundance of helium is a sensitive test of models
  of solar wind formation and of the connection between photospheric,
  coronal, and interplanetary magnetic fields. The observed variations of
  He/H will be discussed in terms of existing models of coronal magnetic
  field topology and solar wind acceleration. This research is supported
  by the NSF/SHINE grant ATM-0327723.

Title: On the Topological Evolution of the Coronal Magnetic Field
    During the Solar Cycle
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 2003ApJ...599.1404W
Altcode:
  Using an axisymmetric model that includes the effects of flux
  emergence and surface transport processes, we calculate the evolution
  of the photospheric magnetic field over the solar cycle and derive
  a corresponding sequence of coronal configurations by means of a
  potential-field source-surface extrapolation. By identifying magnetic
  neutral points and tracking changes in the total flux within each
  topological domain, we construct an overall picture of how open
  and closed flux is transported as the coronal field reverses its
  polarity:1. During the rising phase of the cycle, an X-point forms
  above the emerging flux (represented by a bipole structure) in each
  hemisphere, and the overlying, opposite-polarity field lines are
  ``stripped away'' (reconnected to each side); at the same time, as
  the Sun's axial dipole strength decreases, open field lines from the
  polar coronal holes begin to merge at the equator and close down.2. As
  the rate of flux emergence peaks, the X-point rises toward the source
  surface and the bipole opens up, forming a trailing-polarity hole
  on its poleward side, which evolves into the new-cycle polar hole;
  the leading-polarity open flux on the equatorward side of the bipole
  progressively closes down by merging with its opposite-hemisphere
  counterpart.3. Later in the declining phase of the cycle, the
  opposite-hemisphere bipoles begin to reconnect with each other at an
  equatorial X-point, producing long trailing-polarity loops that rise
  toward the source surface and continue to feed flux into the new-cycle
  polar holes, and short leading-polarity loops that collapse toward the
  photosphere and eventually submerge.We compare the case in which the
  transport of the photospheric field is by supergranular diffusion alone
  with that in which both diffusion and a 20 m s<SUP>-1</SUP> poleward
  flow are present; the latter model is shown to reproduce more closely
  the coronal topologies inferred from the observed photospheric field.

Title: Voyager 1 Studies of the HMF to 81 AU During the Ascending
    Phase of Solar Cycle 23
Authors: Burlaga, L. F.; Ness, N. F.; Wang, Y. -M.; Sheeley, N. R.
Bibcode: 2003AIPC..679...39B
Altcode:
  The paper analyzes the magnetic field strength B and polarity
  observed in the distant heliosphere from 1996 to early 2001 and will be
  discussed in relation to the variation of B from 1978 through 1996. The
  observations extend the results of Burlaga et al. [1]. The polarity of
  the heliospheric magnetic field (HMF) from 1997 to early 2001 is studied
  in relation to the extrapolated position of the heliospheric current
  sheet (HCS). These observations of polarity extend the earlier results
  of Burlaga et al. [2] and Burlaga and Ness [3]. The V1 observations
  of the heliospheric magnetic field strength B agree with Parker's
  model of the global heliospheric magnetic field from 1 to 81 AU and
  from 1978 to 2001, when one considers the solar cycle variations in
  the source magnetic field strength and the latitude/time variation in
  the solar wind speed. Parker's model, without adjustable parameters,
  describe the general tendency for B to decrease with increasing distance
  R from the Sun, and the solar cycle time variations causing the three
  broad increases of B around 1980, 1990, and 2000, and the minima of B
  in 1987 and 1997. The variation of magnetic polarity observed by V1
  and V2 was caused by the increasing latitudinal width of the sector
  zone with increasing solar activity, which in turn was related to
  the increasing maximum latitudinal extent and the decreasing minimum
  latitudinal extent of the footpoints of the HCS.

Title: Linear Polarization Measurements of Chromospheric Emission
    Lines
Authors: Sheeley, N. R., Jr.; Keller, C. U.
Bibcode: 2003ApJ...594.1085S
Altcode:
  We have used the Zurich Imaging Stokes Polarimeter (ZIMPOL I)
  with the McMath-Pierce 1.5 m main telescope on Kitt Peak to obtain
  linear polarization measurements of the off-limb chromosphere with a
  sensitivity better than 1×10<SUP>-5</SUP>. We found that the off-disk
  observations require a combination of good seeing (to show the emission
  lines) and a clean heliostat (to avoid contamination by scattered light
  from the Sun's disk). When these conditions were met, we obtained the
  following principal results:1. Sometimes self-reversed emission lines
  of neutral and singly ionized metals showed linear polarization caused
  by the transverse Zeeman effect or by instrumental cross talk from the
  longitudinal Zeeman effect in chromospheric magnetic fields. Otherwise,
  these lines tended to depolarize the scattered continuum radiation
  by amounts that ranged up to 0.2%.2. Lines previously known to show
  scattering polarization just inside the limb (such as the Na I λ5889 D2
  and the He I λ5876 D3 lines) showed even more polarization above the
  Sun's limb, with values approaching 0.7%.3. The O I triplet at λ7772,
  λ7774, and λ7775 showed a range of polarizations. The λ7775 line,
  whose maximum intrinsic polarizability, P<SUB>max</SUB>, is less than
  1%, revealed mainly Zeeman contributions from chromospheric magnetic
  fields. However, the more sensitive λ7772 (P<SUB>max</SUB>=19%) and
  λ7774 (P<SUB>max</SUB>=29%) lines had relatively strong scattering
  polarizations of approximately 0.3% in addition to their Zeeman
  polarizations. At times of good seeing, the polarization spectra
  resolve into fine structures that seem to be chromospheric spicules.

Title: Modeling the Sun's Large-Scale Magnetic Field during the
    Maunder Minimum
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 2003ApJ...591.1248W
Altcode:
  We use a flux transport model to simulate the evolution of the Sun's
  magnetic dipole moment, polar fields, and open flux under Maunder
  minimum conditions. Even when the rate of active region emergence
  is taken to be a factor of ~30 smaller than in recent solar cycles,
  regular polarity oscillations of the axial dipole and polar fields
  can be maintained if the speed of the poleward surface flow is reduced
  from ~20 to ~10 m s<SUP>-1</SUP> and the source flux emerges at very
  low latitudes (~10°). The axial dipole is then found to have an
  amplitude of the order of 0.5 G, as compared with ~4 G during solar
  cycle 21. The strength of the radial interplanetary field component
  at Earth is estimated to be in the range ~0.3-0.7 nT, about a factor
  of 7 lower than contemporary values. We discuss the implications of
  these weak fields for our understanding of geomagnetic activity and
  cosmic-ray modulation during the Maunder minimum.

Title: On the Fluctuating Component of the Sun's Large-Scale
    Magnetic Field
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 2003ApJ...590.1111W
Altcode:
  The Sun's large-scale magnetic field and its proxies are known to
  undergo substantial variations on timescales much less than a solar
  cycle but longer than a rotation period. Examples of such variations
  include the double activity maximum inferred by Gnevyshev, the large
  peaks in the interplanetary field strength observed in 1982 and 1991,
  and the 1.3-1.4 yr periodicities detected over limited time intervals
  in solar wind speed and geomagnetic activity. We consider the question
  of the extent to which these variations are stochastic in nature. For
  this purpose, we simulate the evolution of the Sun's equatorial dipole
  strength and total open flux under the assumption that the active
  region sources (BMRs) are distributed randomly in longitude. The
  results are then interpreted with the help of a simple random walk
  model including dissipation. We find that the equatorial dipole and open
  flux generally exhibit multiple peaks during each 11 yr cycle, with the
  highest peak as likely to occur during the declining phase as at sunspot
  maximum. The widths of the peaks are determined by the timescale τ~1
  yr for the equatorial dipole to decay through the combined action of
  meridional flow, differential rotation, and supergranular diffusion. The
  amplitudes of the fluctuations depend on the strengths and longitudinal
  phase relations of the BMRs, as well as on the relative rates of flux
  emergence and decay. We conclude that stochastic processes provide a
  viable explanation for the ``Gnevyshev gaps'' and for the existence
  of quasi periodicities in the range ~1-3 yr.

Title: Solar Wind Speed and Temperature Outside 10 AU and the
    Termination Shock
Authors: Whang, Y. C.; Burlaga, L. F.; Wang, Y. -M.; Sheeley,
   N. R., Jr.
Bibcode: 2003ApJ...589..635W
Altcode:
  In this paper we first present a series of pickup proton solar wind
  solutions following the fluid motion in the upwind direction to show
  that the wind speed V and temperature T, at a given r outside 10 AU,
  are primarily functions of the 1 AU wind speed V<SUB>0</SUB>. This
  relationship is attributed to the accumulated effects of the
  pickup proton process on the heating and deceleration of the solar
  wind. Because pickup protons are expected to have similar effects on
  the solar wind at all latitudes in the upwind side of the heliosphere,
  in the second part of the paper, the two formulae V(r, V<SUB>0</SUB>)
  and T(r, V<SUB>0</SUB>) are extended to study the termination shock at
  35° latitude. Wang and Sheeley have an empirical model for calculating
  the 1 AU wind speed V<SUB>0</SUB> from the observed photospheric
  field. We use the simulated wind speed V<SUB>0</SUB> to calculate V
  and T outside 60 AU following the fluid motion; then we can study the
  solar cycle variation of the termination shock. The shock location near
  35° is unambiguously dependent on the solar cycle, with a period of
  approximately 1 solar cycle; the amplitude for variation of the shock
  location is greater than 50 AU. The new result supports the idea that
  the first encounter of Voyager 1 with the termination shock may occur
  during the declining phase of cycle 23. After the first encounter, the
  spacecraft will cross the shock two more times over a period of 8 years.

Title: The Solar Wind and Its Magnetic Sources at Sunspot Maximum
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 2003ApJ...587..818W
Altcode:
  We use in situ measurements from the Advanced Composition
  Explorer and magnetograph data from the National Solar
  Observatory to relate the properties of the solar wind during
  1998-2002 to its source region magnetic fields. The great bulk
  of the solar maximum wind is characterized by low proton speeds
  (v<SUB>p</SUB>~420 km s<SUP>-1</SUP>) and high oxygen charge state
  ratios (n<SUB>O<SUP>7+</SUP></SUB>/n<SUB>O<SUP>6+</SUP></SUB>~0.3). This
  slow wind originates from small, sheared open-field regions located
  near active regions and characterized by very large flux tube expansion
  factors (f<SUB>exp</SUB>&gt;&gt;10) and high footpoint field strengths
  (B<SUB>0</SUB>~30 G). In contrast, the occasional high-speed streams
  emanate from weak-field regions (B<SUB>0</SUB>~5 G) with small expansion
  factors (f<SUB>exp</SUB>~4) and show relatively low charge state
  ratios (n<SUB>O<SUP>7+</SUP></SUB>/n<SUB>O<SUP>6+</SUP></SUB>~0.1)
  their proton velocities (v<SUB>p</SUB>~550 km s<SUP>-1</SUP>) are
  substantially reduced by interactions with the surrounding sea of
  low-speed wind. We attribute the high freeze-in temperatures of the
  slow wind to enhanced heating taking place in the low corona in the
  presence of the very strong, rapidly diverging source fields, which
  are found to be correlated with high mass and energy flux densities
  at the coronal base.

Title: Modeling the Sun's polar fields and open flux during the
    Maunder Minimum
Authors: Wang, Y.; Lean, J.; Sheeley, N.
Bibcode: 2003EAEJA.....2424W
Altcode:
  We use a flux transport model to simulate the evolution of the
  Sun's polar fields and open magnetic flux under Maunder Minimum
  conditions. Even when the rate of active region emergence is taken
  to be a factor of 50--100 smaller than in recent cycles, we find that
  11 yr polarity oscillations of the polar fields can be maintained if
  the speed of the poleward surface flow is reduced from 20 m/s to 10
  m/s and the magnetic flux is assumed to emerge at low latitudes. The
  strength of the radial IMF component is inferred to be in the range
  ∼0.2--0.6 nT, about a factor of 10 weaker than at present but with a
  stronger solar-cycle modulation. We discuss the relationship between
  our simulation results and what is known observationally about the
  Maunder Minimum.

Title: Meridional Flow and the Solar Cycle Variation of the Sun's
    Open Magnetic Flux
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.; Lean, J.
Bibcode: 2002ApJ...580.1188W
Altcode:
  We simulate the evolution of the Sun's large-scale magnetic field
  during solar cycle 21, including the effect of surface transport
  processes and active region emergence. As an important new constraint
  on the model, we have scaled our source fluxes upward to be consistent
  with the average measured strength of the interplanetary magnetic
  field (IMF). By adopting a poleward bulk flow of amplitude ~20-25 m
  s<SUP>-1</SUP> together with a supergranular diffusion rate of ~500
  km<SUP>2</SUP> s<SUP>-1</SUP>, we are then able to match the observed
  variation of the Sun's polar fields and open magnetic flux. The high
  meridional flow speeds, peaking at low latitudes, prevent the buildup
  of an overly strong axisymmetric dipole component at sunspot minimum,
  while accounting for the giant poleward surges of flux and accompanying
  polar field fluctuations observed near sunspot maximum. The present
  simulations also reproduce the large peak in the equatorial dipole
  and IMF strength recorded in 1982.

Title: Polarity reversal of the solar magnetic field during cycle 23
Authors: Wang, Y. -M.; Sheeley, N. R.; Andrews, M. D.
Bibcode: 2002JGRA..107.1465W
Altcode:
  Using magnetograph data, coronagraph observations, and source surface
  extrapolations, we examine the evolution of the photospheric magnetic
  field from 1996 through the 2000-2001 polarity reversal and show how
  this evolution is reflected in coronal holes, coronal streamers, the
  heliospheric current sheet (HCS), and the solar wind. The photospheric
  polarity reversal is completed in the more active Northern Hemisphere
  in late 2000 and then in the Southern Hemisphere in 2001. The polar
  coronal holes disappear in 2000 and start to re-form in 2001; during
  this interval, most of the open magnetic flux resides in the active
  region latitudes, where small coronal holes with strong footpoint
  fields generate predominantly slow solar wind. The nondipolar nature
  of the large-scale coronal field at sunspot maximum gives rise to
  complex streamer/HCS topologies, in which a four-sector structure and
  even a secondary, detached current sheet with cylindrical geometry are
  sometimes present. Comparison of the potential field extrapolations with
  coronagraph and Ulysses observations suggests that the magnetograph
  measurements may have underestimated the strength of the south polar
  field during late 2000.

Title: The effect of increasing solar activity on the Sun's total
and open magnetic flux during multiple cycles: Implications for
    solar forcing of climate
Authors: Lean, J. L.; Wang, Y. -M.; Sheeley, N. R.
Bibcode: 2002GeoRL..29.2224L
Altcode: 2002GeoRL..29x..77L
  We investigate the relationship between solar irradiance and cosmogenic
  isotope variations by simulating with a flux transport model the effect
  of solar activity on the Sun's total and open magnetic flux. As the
  total amount of magnetic flux deposited in successive cycles increases,
  the polar fields build up, producing a secular increase in the open
  flux that controls the interplanetary magnetic field which modulates
  the cosmic ray flux that produces cosmogenic isotopes. Non-axisymmetric
  fields at lower latitudes decay on time scales of less than a year; as
  a result the total magnetic flux at the solar surface, which controls
  the Sun's irradiance, lacks an upward trend during cycle minima. This
  suggests that secular increases in cosmogenic and geomagnetic proxies
  of solar activity may not necessarily imply equivalent secular trends
  in solar irradiance. Questions therefore arise about the interpretation
  of Sun-climate relationships, which typically assume that the proxies
  imply radiative forcing.

Title: Solar Wind Speed and Temperature Outside 10 AU and the
    Termination Shock
Authors: Whang, Y. C.; Burlaga, L. F.; Wang, Y.; Sheeley, N. R.
Bibcode: 2002AGUFMSH11A0376W
Altcode:
  We study the speed V and temperature T of the solar wind in the
  distant heliosphere obtained from pickup proton magnetohydrodynamic
  equations that treat interstellar pickup protons and solar wind protons
  as two distinct proton species. The study uses the 27-day average Omni
  plasma and magnetic field data as input. We obtain 336 sets of numerical
  solutions covering the period from the solar minimum of Cycle 20 in 1976
  to the maximum of Cycle 23; each represents the extrapolation for the
  real solar wind conditions at 1 AU to the distant heliosphere following
  the fluid motion. The result shows that outside 10 AU near the ecliptic
  V and T at a given r are primarily functions of the 1 AU wind speed. The
  maximum of the 1 AU wind speed is 615 km/s occurred on March 1989, the
  minimum at 327 km/s occurred on February 1999. A straight line can be
  used to represent the relation between V and the 1 AU speed for each
  given r; and a parabola can represent the relation for T at each given
  r. These relations are attributed to the accumulated effects of pickup
  proton process in the distant heliosphere. Because pickup protons are
  expected to have similar effects on the solar wind at all latitudes
  on the upwind side of the heliosphere, the relationships for V and T
  are extended to study the solar cycle and latitudinal variation for
  the heliocentric distance of the termination shock. Wang and Sheeley
  have an empirical model to calculate the 1 AU wind speed as a function
  of latitude and longitude from the observed photospheric field. The
  calculated latitudinal variation is consistent with the observational
  results from Ulysses. We use the simulated 1 AU speed to calculate V
  and T at varying r following the fluid motion. Then we can calculate
  the solar cycle variation of the shock distance at all latitudes over
  a 26-year's period. The averaged distance increases with the latitude;
  from ecliptic to the pole the distance increases by a factor of 2.

Title: Characteristics of Coronal Inflows
Authors: Sheeley, N. R., Jr.; Wang, Y. -M.
Bibcode: 2002ApJ...579..874S
Altcode:
  This paper describes coronal inflows observed with the Large Angle
  Spectrometric Coronagraph (LASCO). The inflows are not seen above
  5.5 R<SUB>solar</SUB>, which appears to be a ``point of no return''
  for the Sun's plasmas and fields. Below this height, most inflows
  seem to indicate magnetic flux that is returning to the Sun after its
  reconnection at sector boundaries. Some inflows have characteristics
  (like fast, oppositely directed ejections of material) that are
  easily interpreted in terms of conventional models of field line
  reconnection. However, the overwhelming majority of coronal inflows
  have a more complex behavior that typically includes the following
  characteristics:1. The birth of a very weak, localized density
  enhancement about 4-5 R<SUB>solar</SUB> from Sun center and its
  initially slow downward motion along a coronal ray;2. Acceleration
  to a maximum speed of 50-100 km s<SUP>-1</SUP>, and the formation
  of a sinking column;3. Deceleration and the appearance of a dark
  depletion tail, visible against the bright background structures in
  the lower corona;4. The formation of a stretched loop below about
  2.5 R<SUB>solar</SUB>.We suppose that the initial downward motion is
  a preparatory stage for reconnection, which occurs in the depleted
  region in the wake of the sinking column and is later revealed by the
  formation of a stretched loop in the lower corona.

Title: Heliospheric magnetic field strength and polarity from 1 to
    81 AU during the ascending phase of solar cycle 23
Authors: Burlaga, L. F.; Ness, N. F.; Wang, Y. -M.; Sheeley, N. R.
Bibcode: 2002JGRA..107.1410B
Altcode:
  The Voyager 1 (V1) observations of the heliospheric magnetic field
  strength B agree with Parker's model of the global heliospheric magnetic
  field from 1 to 81.0 AU and from 1978 to 2001.34 when one considers
  the solar cycle variations in the source magnetic field strength and
  the latitude/time variation in the solar wind speed. In particular,
  Parker's model, without adjustable parameters, describes the general
  tendency for B to decrease with increasing distance R from the Sun, the
  three broad increases of B around 1980, 1990, and 2000, and the minima
  of B in 1987 and 1997. During 1987 and 1997, B appears to be lower than
  Parker's model predicts, but that can be attributed to the presence
  of a heliospheric vortex street at these times and/or uncertainty
  in the observations. There is no evidence for a significant flux
  deficit increasing monotonically from 1 to 81.0 AU. By extrapolating
  these results and considering the limitations of the observations,
  V1 should continue to make useful measurements during the next few
  years at least. The magnetic field polarity in the distant heliosphere
  at V1 and Voyager 2 (V2) changed during the ascending phase of solar
  cycle 23. In the Northern Hemisphere, V1 observed a decrease in the
  percentage of positive polarities from ≈100% during 1997 to ≈50%
  during 2000. In the Southern Hemisphere, V2 observed the opposite
  behavior, an increase in the percentage of positive polarities from
  ≈0% during 1997 to ≈50% during 2000. The variation of magnetic
  polarity observed by V1 and V2 was caused by the increasing latitudinal
  width of the sector zone with increasing solar activity, which in
  turn was related to the increasing maximum latitudinal extent and
  the decreasing minimum latitudinal extent of the footprints of the
  heliospheric current sheet (HCS). There was a tendency for the speed
  and proton temperature to decrease and the density to increase at V2
  from 1997 (when it observed flows from polar coronal holes) to 2001
  (when it observed more complex and dynamic flows).

Title: Sunspot activity and the long-term variation of the Sun's
    open magnetic flux
Authors: Wang, Y. -M.; Sheeley, N. R.
Bibcode: 2002JGRA..107.1302W
Altcode:
  The interplanetary magnetic field (IMF) originates in open magnetic
  regions of the Sun (coronal holes), which in turn form mainly through
  the emergence and dispersal of active region fields. The radial IMF
  strength is proportional to the total open flux Φ<SUB>open</SUB>, which
  can be estimated from source surface extrapolations of the measured
  photospheric field, after correction for magnetograph saturation
  effects. We derive the long-term variation of Φ<SUB>open</SUB> during
  1971-2000 and discuss its relation to sunspot activity. The average
  value of Φ<SUB>open</SUB> was ∼20-30% higher during 1976-1996 than
  during 1971-1976 and 1996-2000, with major peaks occurring in 1982
  and 1991. Near sunspot minimum, most of the open flux resides in the
  large polar coronal holes, whereas at sunspot maximum it is rooted
  in relatively small, low-latitude holes located near active regions
  and characterized by strong footpoint fields; since the decrease in
  the total area occupied by holes is offset by the increase in their
  average field strengths, Φ<SUB>open</SUB> remains roughly constant
  between activity minimum and maximum, unlike the total photospheric
  flux Φ<SUB>tot</SUB>. The long-term variation of Φ<SUB>open</SUB>
  approximately follows that of the Sun's total dipole strength, with a
  contribution from the magnetic quadrupole around sunspot maximum. Global
  fluctuations in sunspot activity lead to increases in the equatorial
  dipole strength and hence to enhancements in Φ<SUB>open</SUB> and
  the IMF strength lasting typically ∼1 year. We employ simulations to
  clarify the role of active region emergence and photospheric transport
  processes in the evolution of the open flux. Representing the initial
  field configuration by one or more bipolar magnetic regions (BMRs), we
  calculate its subsequent evolution under the influence of differential
  rotation, supergranular convection, and a poleward bulk flow. The
  initial value of Φ<SUB>open</SUB> is determined largely by the
  equatorial dipole strength, which in turn depends on the longitudinal
  phase relations between the BMRs. As the surface flow carries the BMR
  flux to higher latitudes, the equatorial dipole is annihilated on a
  timescale of ∼1 year by the combined effect of rotational shearing and
  turbulent diffusion. The remaining flux becomes concentrated around the
  poles, and Φ<SUB>open</SUB> approaches a limiting value that depends
  on the axisymmetric dipole strengths of the original BMRs. The polar
  coronal holes thus represent the long-lived, axisymmetric remnant of
  the active regions that emerged earlier in the cycle.

Title: A comparison of mean density and microscale density
    fluctuations in a CME at 10 R<SUB>solar</SUB>
Authors: Lynch, B. J.; Coles, W. A.; Sheeley, N. R.
Bibcode: 2002GeoRL..29.1913L
Altcode: 2002GeoRL..29s..19L
  We have observed intensity scintillation (IPS) of the radio source 0854
  + 201 at 8 GHz on August 2, 2000 during the passage of a coronal mass
  ejection (CME) across the line of sight. The source was at a distance
  of 10 R<SUB>solar</SUB> over the north solar pole. Simultaneous
  observations with the LASCO C3 instrument allow us to model the
  mean density N<SUB>e</SUB> and the microscale density fluctuations
  δN<SUB>e</SUB> within the CME. We find that N<SUB>e</SUB> increased
  by a factor of 2.18 but δN<SUB>e</SUB> increased by only 1.76, so
  the ratio δN<SUB>e</SUB>/N<SUB>e</SUB> is 19% smaller than in the
  pre-CME slow wind. During the passage of the CME a short burst of
  enhanced turbulence doubled the IPS variance but was not visible in
  the C3 images. This was likely caused by a thin flux tube crossing
  the line of sight. Detailed modeling indicates that the diameter of
  the tube was 41,000 km and its density was 14.5 times the CME density.

Title: Role of a Variable Meridional Flow in the Secular Evolution
    of the Sun's Polar Fields and Open Flux
Authors: Wang, Y. -M.; Lean, J.; Sheeley, N. R., Jr.
Bibcode: 2002ApJ...577L..53W
Altcode:
  We use a magnetic flux transport model to simulate the evolution of
  the Sun's polar fields and open flux during solar cycles 13 through 22
  (1888-1997). The flux emergence rates are assumed to scale according to
  the observed sunspot-number amplitudes. We find that stable polarity
  oscillations can be maintained if the meridional flow rate is allowed
  to vary from cycle to cycle, with higher poleward speeds occurring
  during the more active cycles. Our model is able to account for a
  doubling of the interplanetary field strength since 1900, as deduced
  by Lockwood, Stamper, &amp; Wild from the geomagnetic aa index. We
  confirm our earlier conclusion that such a doubling of the open flux
  does not imply that the base level of the total photospheric flux has
  increased significantly over the last century.

Title: Coronal White-Light Jets near Sunspot Maximum
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 2002ApJ...575..542W
Altcode:
  During the 1996-1997 activity minimum, the Large Angle and Spectrometric
  Coronagraph (LASCO) on the Solar and Heliospheric Observatory (SOHO)
  recorded numerous jetlike ejections above the Sun's polar regions. In
  a previous study, we showed that these white-light ejections were
  the outward extensions of extreme-ultraviolet (EUV) jets, which in
  turn originated from flaring bright points inside the polar coronal
  holes. Here we investigate a number of jetlike events observed with
  LASCO during the current sunspot maximum. To identify the solar surface
  counterparts of these events, we again use Fe XII λ195 images obtained
  by the EUV Imaging Telescope on SOHO. The white-light jets in our sample
  have angular widths of ~3°-7° and velocities typically of order 600 km
  s<SUP>-1</SUP> they tend to be brighter and wider than the polar jets
  observed near sunspot minimum and are distributed over a much greater
  range of latitudes. Many of the ejections are recurrent in nature and
  originate from active regions located inside or near the boundaries
  of nonpolar coronal holes. We deduce that the jet-producing regions
  consist of systems of closed magnetic loops partially surrounded by
  open fields; perturbations in the closed fields caused them to reconnect
  with the overlying open flux, releasing the trapped energy in the form
  of jetlike ejections. In some events, the core of the active region
  erupts, producing fast, collimated ejections with widths of up to ~15°.

Title: Solar Energetic Particle Production by Shocks in Fast and
    Slow Solar Wind Structures
Authors: Kahler, S. W.; Reames, D. V.; Sheeley, N. R., Jr.
Bibcode: 2002AAS...200.3702K
Altcode: 2002BAAS...34..694K
  Gradual solar energetic particle (SEP) events at 1 AU are produced
  by coronal and interplanetary shocks driven by coronal mass ejections
  (CMEs). Shocks from fast (V &gt; 900 km/s) CMEs should be produced more
  easily in slow solar wind regions where the flow and fast-mode MHD wave
  speeds are low and less easily in fast solar wind regions where those
  speeds are high. We might therefore expect to observe more intense SEP
  events at 1 AU when the Earth lies in a slow wind region than when it
  lies in a fast wind region. While stream-stream interactions wash out
  the slow-fast stream boundaries in the solar wind speed profiles at
  1 AU, the O+7/O+6 signatures of the streams are unchanged at 1 AU. We
  use the 20 MeV proton intensities from the EPACT instrument on Wind,
  the associated CMEs observed with the Lasco coronagraph on SOHO,
  and the ACE SWICS/SWIMS solar wind values of O+7/O+6 to look for
  variations of peak SEP intensities as a function of O+7/O+6. We find
  no significant dependence of the SEP intensities on O+7/O+6 for either
  poorly connected or well connected CME source regions or for different
  CME speed ranges. While a broad range of angular widths are associated
  with fast (V &gt; 900 km/s) CMEs, we find that no fast CMEs with widths
  &lt; 60 degrees are associated with SEP events. On the other hand,
  nearly all fast halo CMEs are associated with SEP events. Thus the CME
  widths are more important in SEP production than previously thought,
  but the solar wind source regions in which SEPs are produced are not
  a significant factor.

Title: Observations of Core Fallback during Coronal Mass Ejections
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 2002ApJ...567.1211W
Altcode:
  White-light observations made with the Large Angle and Spectrometric
  Coronagraph (LASCO) during the present solar maximum have revealed a
  multitude of faint, inward-moving features at heliocentric distances of
  r~2-6 R<SUB>solar</SUB>. Most of these structures appear to originate
  above r~3 R<SUB>solar</SUB> and may be signatures of the closing-down
  of magnetic flux at the boundaries of coronal holes or in the aftermath
  of coronal mass ejections (CMEs). Here, we present observations of a
  different type of inflow, in which material within the bright core of
  a CME collapses back toward the Sun after rising to heights of r~2.5-6
  R<SUB>solar</SUB>. We have identified roughly 20 such fallback events
  during 1998-2001. The core structures, which have the form of loops or
  concave-outward flux ropes, ascend into the coronagraph field of view
  beyond 2 R<SUB>solar</SUB> with speeds of ~100-400 km s<SUP>-1</SUP>
  but return with speeds of only ~50-200 km s<SUP>-1</SUP>. The initial
  deceleration rates of ~20-100 m s<SUP>-2</SUP> are comparable to the
  local gravitational deceleration GM<SUB>solar</SUB>/r<SUP>2</SUP>
  but continually decrease with time. The associated CMEs tend to be
  impulsive but relatively slow, with the leading front moving outward
  at ~250-450 km s<SUP>-1</SUP> and often showing some deceleration. It
  is thus not surprising that some fraction of the core material fails
  to reach escape speeds, remaining bound to the Sun by gravitational
  and magnetic tension forces. We suggest that the dynamical behavior
  of the core may be determined in part by momentum exchanges with the
  background medium, which consists of ongoing outflows of CME material,
  ambient solar wind, and inflow streams. In particular, we attribute the
  asymmetry of the up-down trajectories to the action of such drag forces,
  whose direction changes from inward to outward as the core decelerates.

Title: Coronal Mass Ejections Associated with Impulsive Solar
    Energetic Particle Events
Authors: Kahler, S. W.; Reames, D. V.; Sheeley, N. R., Jr.
Bibcode: 2001ApJ...562..558K
Altcode:
  An impulsive solar energetic particle (SEP) event observed on the
  Wind spacecraft on 2000 May 1 was associated with an impulsive solar
  active region M1 X-ray flare. The timing and position of a fast (v=960
  km s<SUP>-1</SUP>), narrow CME observed in the LASCO coronagraph on
  SOHO make clear the connection between the CME and the flare and SEP
  event. Impulsive SEP events have long been associated with impulsive
  flares, but only gradual SEP events have thus far been found to be
  associated with CMEs. A comparison of impulsive SEP events with CME
  observations from the Solwind and LASCO coronagraphs revealed further
  good cases of narrow (10°-40°) CMEs associated with impulsive SEP
  events. A recent model of impulsive flares includes jets or plasmoids
  that are ejected upward from magnetic reconnection sites over active
  regions and might therefore be expected to appear in exceptional
  cases as faint and narrow CMEs in coronagraphs. We suggest that this
  model allows us to understand better SEP production and propagation
  in impulsive flares.

Title: Coronal Inflows and Sector Magnetism
Authors: Sheeley, N. R., Jr.; Wang, Y. -M.
Bibcode: 2001ApJ...562L.107S
Altcode:
  We have remeasured the rate of coronal inflows during 1996-2001,
  taking into account multiple occurrences per day, and have displayed the
  results in Carrington stack plots to study their long-term behavior. The
  stack plots show long-lived recurrence patterns related to the sectorial
  component of the Sun's large-scale field. In particular, most inflows
  are parts of streams that last for several months and occur where the
  sectorial field has strong gradients. The occurrence rate occasionally
  approaches ~1 hr<SUP>-1</SUP> near sunspot maximum when the sectorial
  field is strong and the streamer belt is greatly distorted from its
  flattened equatorial configuration. The link between coronal inflows
  and sector magnetism suggests that the inflows are by-products of
  a global recycling process in which nonaxisymmetric open flux is
  provided by active regions and dissipated by differential rotation,
  supergranular diffusion, and meridional flow.

Title: Associations of Accelerating CMEs with Solar Energetic
    Particle Events
Authors: Kahler, S.; Sheeley, N.; Reames, D.
Bibcode: 2001AGUSM..SH22B03K
Altcode:
  Gradual solar energetic particle (SEP) events are well associated with
  fast coronal mass ejections (CMEs). The times of significant E &gt;
  10 MeV SEP events observed with the Goddard Space Flight Center EPACT
  detector on the Wind spacecraft have been compared with CME observations
  from the Lasco coronagraph on the SOHO spacecraft. As earlier studies
  have shown, a correlation exists between peak SEP intensities and
  the measured speeds of associated CMEs. Of the CMEs associated with
  SEP events in the period 1996 to 2000, we find 9 CMEs for which the
  height-time plots of the leading edges show accelerations of at least
  13 m/s/s. The heights at which those CMEs attained speeds of 600 km/s
  ranged from 7 to 20 Ro. The peak 20 MeV intensities of the 9 SEP events
  are relatively low compared with all gradual SEP events of the same
  period. We compare the energy spectra and solar event associations of
  these 9 SEP events with those of the SEP events associated with CMEs
  of uniform speeds.

Title: Coronal Inflows and the Sun's Nonaxisymmetric Open Flux
Authors: Sheeley, N. R., Jr.; Knudson, T. N.; Wang, Y. -M.
Bibcode: 2001ApJ...546L.131S
Altcode:
  Wang et al. recently described white-light coronagraph observations
  of faint coronal features moving inward toward the Sun at heliocentric
  distances of 2-6 R<SUB>solar</SUB>. In a study of these inflows during
  1996-2000, we have found that they occur along bends of the coronal
  streamer belt and are especially common when the magnetic field has
  a four-sector structure. The measured inflow rate is dominated by
  episodic bursts that are correlated with the occurrence of nonpolar
  coronal holes and other indicators of the Sun's nonaxisymmetric open
  flux. However, the inflow rate has only a broad long-term correlation
  with conventional indicators of solar activity like the sunspot
  number and coronal mass ejection rate. We conclude that most inflows
  indicate collapsing field lines that occur as nonpolar coronal holes
  are subjected to photospheric motions and the eruptions of new flux.

Title: The dynamical nature of coronal streamers
Authors: Wang, Y. -M.; Sheeley, N. R.; Socker, D. G.; Howard, R. A.;
   Rich, N. B.
Bibcode: 2000JGR...10525133W
Altcode:
  Recent high-sensitivity imaging of the Sun's white-light corona from
  space has revealed a variety of unexpected small-scale phenomena,
  including plasma blobs that are ejected continually from the
  cusplike bases of streamers, fine raylike structures pervading the
  outer streamer belt, and inflows that occur mainly during times of
  high solar activity. These phenomena can be interpreted as different
  manifestations of magnetic field line reconnection, in which plasma
  and magnetic flux are exchanged between closed and open field regions
  of the corona. The observations provide new insights into a number
  of long-standing questions, including the origin of the streamer
  material in the outer corona, the sources of the slow solar wind, and
  the mechanisms that regulate the interplanetary magnetic field strength.

Title: Detection of coronal mass ejection associated shock waves in
    the outer corona
Authors: Sheeley, N. R.; Hakala, W. N.; Wang, Y. -M.
Bibcode: 2000JGR...105.5081S
Altcode:
  White light coronal images from the Large-Angle Spectrometric
  Coronagraph (LASCO) on the Solar and Heliospheric Observatory (SOHO)
  spacecraft show disturbances propagating away from high-speed coronal
  mass ejections (CMEs). The disturbances are faintly visible ahead
  of the ejected material at the noses of the CMEs but are strongly
  visible along the flanks and rear ends, where they produce kinks in
  the streamers and other raylike features that extend in all directions
  from the Sun at this phase of the sunspot cycle. The kinks decelerate
  as they move radially outward along the rays, apparently indicating the
  slowing of the entire wave front as it passes by. For a fast CME seen
  head on (or tail on) the deceleration occurs at virtually all position
  angles around the occulting disk. However, for a CME seen obliquely
  the speed varies strongly with position angle, being fast and uniform
  near the nose but slower and decelerating at the sides and rear where
  the deflected rays are more inclined from the sky plane and farther
  from the Sun. The initial speeds (~800-1400 km/s) are faster than the
  nominal MHD speed (~600 km/s) at these heights, implying that these
  disturbances are shock waves, made visible like ``amber waves of grain''
  [Bates, 1895] in the field of coronal rays around the Sun.

Title: Understanding the evolution of the Sun's open magnetic flux
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.; Lean, J.
Bibcode: 2000GeoRL..27..621W
Altcode:
  The large-scale magnetic field of the Sun, including the open flux that
  extends into the interplanetary medium, originates in active regions
  but is redistributed over the photosphere by differential rotation,
  supergranular convection, and poleward meridional flow. We use
  simulations to clarify the role of the surface transport processes
  in the evolution of the total open flux, Φ<SUB>open</SUB>,
  which determines the strength of the radial interplanetary field
  component. Representing the initial photospheric field configuration
  by one or more bipolar magnetic regions (BMRs), we show that
  Φ<SUB>open</SUB> varies approximately as the net dipole strength,
  determined by vectorially summing the dipole moments of the individual
  BMRs. As meridional flow carries the BMR flux to higher latitudes,
  the equatorial dipole component is annihilated on a timescale ∼1
  yr by the combined effect of rotational shearing and supergranular
  diffusion. The remaining flux becomes concentrated around the poles,
  and Φ<SUB>open</SUB> approaches a limiting value that depends on
  the axisymmetric dipole strength of the original active regions. We
  discuss the implications of these results for the solar cycle evolution
  of Φ<SUB>open</SUB>.

Title: The long-term variation of the Sun's open magnetic flux
Authors: Wang, Y. -M.; Lean, J.; Sheeley, N. R., Jr.
Bibcode: 2000GeoRL..27..505W
Altcode:
  The interplanetary magnetic field (IMF) has its origin in open magnetic
  regions of the Sun (coronal holes). The location of these regions
  and their total open flux Φ<SUB>open</SUB> can be inferred from
  current-free extrapolations of the observed photospheric field. We
  derive the long-term variation of Φ<SUB>open</SUB> during 1971-1998
  and discuss its causes. Near sunspot minimum, the open flux originates
  mainly from the large polar coronal holes, whereas at sunspot maximum
  it is rooted in small, lower-latitude holes characterized by very high
  field strengths; the total amount of open flux thus remains roughly
  constant between sunspot minimum and maximum. Through most of the
  cycle, the variation of Φ<SUB>open</SUB> closely follows that of the
  Sun's total dipole strength, showing much less dependence on the total
  photospheric flux or the sunspot number. However, episodic increases in
  large-scale sunspot activity lead to strengthenings of the equatorial
  dipole component, and hence to enhancements in Φ<SUB>open</SUB>
  and the IMF strength lasting typically ∼1 yr.

Title: Evolution of coronal streamer structure during the rising
    phase of solar cycle 23
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.; Rich, N. B.
Bibcode: 2000GeoRL..27..149W
Altcode:
  White-light images of the outer corona recorded with the Large Angle
  Spectrometric Coronagraph (LASCO) on the Solar and Heliospheric
  Observatory (SOHO) show a rapid widening of the streamer belt during
  1998 and early 1999. The observed streamer structure and its evolution
  from rotation to rotation are reproduced with a model in which the
  Thomson-scattering electrons are concentrated within a narrow layer
  centered around the heliospheric current sheet. The latitudinal
  spreading of the streamer belt is shown to be a consequence of the
  increased rate of magnetic flux emergence in the sunspot latitudes,
  which led to a weakening of the Sun’s axisymmetric dipole moment, to
  a rapid growth in the nonaxisymmetric components of the coronal field,
  and hence to a strong tilting and warping of the plasma/current sheet.

Title: Continuous tracking of coronal outflows: Two kinds of coronal
    mass ejections
Authors: Sheeley, N. R.; Walters, J. H.; Wang, Y. -M.; Howard, R. A.
Bibcode: 1999JGR...10424739S
Altcode:
  We have developed a new technique for tracking white-light coronal
  intensity features and have used this technique to construct continuous
  height/time maps of coronal ejecta as they move outward through the
  2-30R<SUB>s</SUB> field of view of the Large-Angle Spectrometric
  Coronagraph (LASCO) on the Solar and Heliospheric Observatory (SOHO)
  spacecraft. Displayed as gray-scale images, these height/time maps
  provide continuous histories of the motions along selected radial paths
  in the corona and reveal a variety of accelerating and decelerating
  features, including two principal types of coronal mass ejections
  (CMEs): (1) Gradual CMEs, apparently formed when prominences and their
  cavities rise up from below coronal streamers: When seen broadside,
  these events acquire balloon-like shapes containing central cores,
  and their leading edges accelerate gradually to speeds in the range
  400-600 km/s before leaving the 2-30R<SUB>s</SUB> field of view. The
  cores fall behind with speeds in the range 300-400 km/s. Seen along
  the line of sight, these events appear as smooth halos around the
  occulting disk, consistent with head-on views of optically thin bubbles
  stretched out from the Sun. At the relatively larger radial distances
  seen from this ``head-on'' perspective, gradually accelerating CMEs
  fade out sooner and seem to reach a constant speed more quickly than
  when seen broadside. Some suitably directed gradual CMEs are associated
  with interplanetary shocks and geomagnetic storms. (2) Impulsive CMEs,
  often associated with flares and Moreton waves on the visible disk: When
  seen broadside, these CMEs move uniformly across the 2-30R<SUB>s</SUB>
  field of view with speeds typically in excess of 750 km/s. At the
  relatively larger radial distances seen from a head-on perspective,
  impulsive events tend to have a more ragged structure than the gradual
  CMEs and show clear evidence of deceleration, sometimes reducing their
  speeds from 1000 to 500 km/s in 1 hour. Such decelerations are too large
  to represent ballistic motions in the Sun's gravitational field but
  might be caused by shock waves, sweeping up material far from the Sun.

Title: Using LASCO observations to infer solar wind speed near the sun
Authors: Sheeley, N. R.
Bibcode: 1999AIPC..471...41S
Altcode: 1999sowi.conf...41S
  No abstract at ADS

Title: Coronagraph observations of inflows during high solar activity
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.; Howard, R. A.; Cyr,
   O. C. St.; Simnett, G. M.
Bibcode: 1999GeoRL..26.1203W
Altcode:
  Since the start of the SOHO mission three years ago, the Large Angle
  Spectrometric Coronagraph (LASCO) has recorded numerous examples of
  small, faint features moving inward through the corona. The inflows
  are observed at heliocentric distances of 2-4 R<SUB>s</SUB> and became
  increasingly common during 1998, as solar and coronal mass ejection
  (CME) activity increased. The inward-moving structures, which are most
  easily detected in running difference movies, often have a cusplike
  appearance and tend to leave a density depletion in their wake; the
  downward velocities range from less than 20 km s<SUP>-1</SUP> to over
  100 km s<SUP>-1</SUP>. The downflows are observed typically ∼1 day
  after the passage of a CME, and coexist side by side with continuing
  outflows of streamer material. We interpret these small-scale events
  as observational signatures of the gradual closing-down of magnetic
  flux dragged outward by CMEs or other transient outflows.

Title: Streamer disconnection events observed with the LASCO
    coronagraph
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.; Howard, R. A.; Rich,
   N. B.; Lamy, P. L.
Bibcode: 1999GeoRL..26.1349W
Altcode:
  We present Large Angle Spectrometric Coronagraph (LASCO) observations
  of two events that suggest magnetic disconnection in coronal
  streamers. During the 1-2 days preceding each event, successions of
  narrow looptops are seen rising slowly through the 2-6 R<SUB>S</SUB>
  field of view, forming a bright streamer stalk which continues to
  elongate with time. As the streamer becomes ever more constricted, it
  eventually severs at a heliocentric distance of ∼4 R<SUB>S</SUB>. The
  lower part of the stalk collapses back to form a cusplike structure
  extending to ∼3 R<SUB>S</SUB>, while the disconnected segment is
  observed as a kink or density enhancement that propagates outward with
  a speed of order 200 km s<SUP>-1</SUP>. We interpret these non-CME
  events as transient openings and closings of magnetic flux rooted at
  the boundaries of coronal holes.

Title: The Increase in Mass of CMEs due to Propagation
Authors: Howard, R. A.; Dere, K. P.; Sheeley, N. R., Jr.; Subramanian,
   P.; Vourlidas, A.; Wang, D.
Bibcode: 1999AAS...19410102H
Altcode: 1999BAAS...31..998H
  The question we would like to address is whether coronal mass ejections
  snowplow ambient material. Some of the CMEs observed by the LASCO
  coronagraph on SOHO have a clearly defined loop-like front, meaning
  that the trailing edge of the front can be clearly defined. We measure
  the mass in the front of the CME in this subclass. We find that for
  some of the events, the mass in the leading edge increases, implying
  that the CME is indeed "snowplowing" ambient material. If there is a
  significant increase in mass, then the CME frontal speed might decrease
  to conserve momentum. We estimate the amount of ambient material,
  using a model of coronal densities, and find that it is consistent
  with the mass increase. We can also estimate the height in the corona,
  below the occulting disk, from where the original material in the CME
  is released. These concepts as well as conditions for when the mass
  increases will be discussed.

Title: Filament Eruptions near Emerging Bipoles
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 1999ApJ...510L.157W
Altcode:
  It has been suggested in previous studies that quiescent prominences
  and filaments erupt preferentially in the vicinity of emerging
  magnetic flux. We describe three such filament eruptions observed
  during 1998 with the Extreme-ultraviolet Imaging Telescope on the
  Solar and Heliospheric Observatory. Comparison with magnetograms and
  with potential field extrapolations suggests that the new bipole
  enables the eruption by diverting the flux overlying the filament
  sideways or to greater heights, allowing the filament to rise out of
  its channel. Because eruptions sometimes occur in the absence of any
  observable flux emergence, however, we conclude that new flux may act
  as a strong catalyst but is not a necessary condition for filament
  destabilization.

Title: Scattering polarization in the chromosphere
Authors: Keller, C. U.; Sheeley, N. R., Jr.
Bibcode: 1999ASSL..243...17K
Altcode: 1999sopo.conf...17K
  No abstract at ADS

Title: Observations of Correlated White-Light and Extreme-Ultraviolet
    Jets from Polar Coronal Holes
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.; Socker, D. G.; Howard,
   R. A.; Brueckner, G. E.; Michels, D. J.; Moses, D.; St. Cyr, O. C.;
   Llebaria, A.; Delaboudinière, J. -P.
Bibcode: 1998ApJ...508..899W
Altcode:
  Time-lapse sequences of white-light images recorded with the Large
  Angle Spectrometric Coronagraph (LASCO) on the Solar and Heliospheric
  Observatory (SOHO) frequently show long, narrow structures moving
  outward over the Sun's polar regions at high apparent speeds. By
  comparing the LASCO observations with Fe XII λ195 spectroheliograms
  made with the Extreme-ultraviolet Imaging Telescope (EIT) on SOHO
  between 1997 April and 1998 February, we have identified 27 correlated
  white-light and extreme-ultraviolet (EUV) jet events. In each case,
  the EUV jet was observed near the limb of the polar coronal hole 20-60
  minutes before the corresponding white-light jet was registered in the
  coronagraph's 2-6 R<SUB>⊙</SUB> field of view. The jets originate
  near flaring EUV bright points and are presumably triggered by field
  line reconnection between magnetic bipoles and neighboring unipolar
  flux. The leading edges of the white-light jets propagate outward at
  speeds of 400-1100 km s<SUP>-1</SUP>, whereas the bulk of their material
  travels at much lower velocities averaging around 250 km s<SUP>-1</SUP>
  at heliocentric distances of 2.9-3.7 R<SUB>⊙</SUB>. These lower
  velocities may reflect the actual outflow speeds of the background
  polar wind.

Title: Heliospheric magnetic field strength out to 66 AU: Voyager
    1, 1978-1996
Authors: Burlaga, L. F.; Ness, N. F.; Wang, Y. -M.; Sheeley, N. R.
Bibcode: 1998JGR...10323727B
Altcode:
  We discuss Voyager 1 (V1) observations of the heliospheric magnetic
  field strength from 1978 through 1996. During this period the distance
  of V1 from the Sun increased from ~3 AU to 66 AU and its heliographic
  latitude increased from ~5°S to 33°N. The magnetic field strength
  profile observed by V1 is consistent with Parker's spiral field model
  when one considers (1) the solar cycle variation of the observed
  magnetic field strength at 1 AU, B<SUB>1</SUB>(t) (which is a measure
  of the source field strength) and (2) the latitudinal and solar cycle
  variations of the solar wind speed, V(t,θ). Both B<SUB>1</SUB>(t) and
  V(t,θ) make significant contributions to the variation of the magnetic
  field strength variations observed by V1. There is no evidence for a
  ``magnetic flux deficit'' increasing with distance from the Sun. There
  is a solar cycle variation of the magnetic field strength in the outer
  heliosphere, which will affect the modulation of cosmic rays.

Title: Large-scale coronal heating by the small-scale magnetic field
    of the Sun
Authors: Schrijver, C. J.; Title, A. M.; Harvey, K. L.; Sheeley,
   N. R.; Wang, Y. -M.; van den Oord, G. H. J.; Shine, R. A.; Tarbell,
   T. D.; Hurlburt, N. E.
Bibcode: 1998Natur.394..152S
Altcode:
  Magnetic fields play a crucial role in heating the outer atmospheres
  of the Sun and Sun-like stars, but the mechanisms by which magnetic
  energy in the photosphere is converted to thermal energy in the corona
  remain unclear. Observations show that magnetic fields emerge onto
  the solar surface as bipolar regions with a broad range of length
  scales. On large scales, the bipolar regions survive for months before
  dispersing diffusively. On the smaller scales, individual bipolar
  regions disappear within days but are continuously replenished by new
  small flux concentrations, resulting in a sustained state of mixed
  polarity. Here we determine the rate of emergence of these small
  bipolar regions and we argue that the frequent magnetic reconnections
  associated with these regions (an unavoidable consequence of continued
  flux replacement) will heat the solar atmosphere. The model that
  describes the details of these mixed-polarity regions is complementary
  to the traditional diffusion model for large-scale flux dispersal and
  a combination of the two should lead to a more complete understanding
  of the role of magnetic fields in stellar atmospheres.

Title: Origin of Streamer Material in the Outer Corona
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.; Walters, J. H.; Brueckner,
   G. E.; Howard, R. A.; Michels, D. J.; Lamy, P. L.; Schwenn, R.;
   Simnett, G. M.
Bibcode: 1998ApJ...498L.165W
Altcode:
  We investigate the nature and origin of the outward-moving density
  inhomogeneities (``blobs'') detected previously with the Large Angle and
  Spectrometric Coronagraph on the Solar and Heliospheric Observatory. The
  blobs are concentrated around the thin plasma layer that surrounds
  the heliospheric current sheet and that constitutes the outer streamer
  belt; they represent only a small, fluctuating component of the total
  density within the plasma sheet. As noted before in Sheeley et al.,
  blobs are characterized by low speeds and are continually emitted
  from the elongated tips of helmet streamers at 3-4 R<SUB>solar</SUB>
  from Sun center. We suggest that both the blobs and the plasma sheet
  itself represent closed-field material injected into the solar wind as
  a result of footpoint exchanges between the stretched helmet-streamer
  loops and neighboring open field lines. The plasma sheet is thus
  threaded by newly reconnected, open magnetic field lines, which lend
  the white-light streamer belt its filamentary appearance. Since in
  situ observations at 1 AU show that the slow wind (with speeds below
  500 km s<SUP>-1</SUP>) spreads over an angular extent much greater
  than the &lt;~3° width of the plasma sheet, we deduce that a major
  component of this wind must originate outside the helmet streamers
  (i.e., from just inside coronal holes).

Title: White-Light Coronal Mass Ejections: A New Perspective from
    LASCO
Authors: St. Cyr, O. C.; Howard, R. A.; Simnett, G. M.; Gurman, J. B.;
   Plunkett, S. P.; Sheeley, N. R.; Schwenn, R.; Koomen, M. J.; Brueckner,
   G. E.; Michels, D. J.; Andrews, M.; Biesecker, D. A.; Cook, J.; Dere,
   K. P.; Duffin, R.; Einfalt, E.; Korendyke, C. M.; Lamy, P. L.; Lewis,
   D.; Llebaria, A.; Lyons, M.; Moses, J. D.; Moulton, N. E.; Newmark,
   J.; Paswaters, S. E.; Podlipnik, B.; Rich, N.; Schenk, K. M.; Socker,
   D. G.; Stezelberger, S. T.; Tappin, S. J.; Thompson, B.; Wang, D.
Bibcode: 1997ESASP.415..103S
Altcode: 1997cpsh.conf..103S
  No abstract at ADS

Title: The high-latitude solar wind near sunspot Maximum
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 1997GeoRL..24.3141W
Altcode:
  We use an empirical relation between solar wind speed and coronal
  flux-tube expansion to predict what Ulysses might have seen had it
  flown over the solar poles during 1989-1991 instead of 1994-1996. The
  wind speed patterns, derived from solar magnetograph data, show the
  following characteristics: (1) high-speed streams having recurrence
  rates of 28-29 days and originating from midlatitude extensions of the
  polar coronal holes dominate the rising phase of the sunspot cycle
  (1987-1989) (2) the persistent high-speed polar wind disappears and
  low-speed wind is found at all latitudes during 1989-1990 (3) very fast,
  episodic “polar jets” are generated as active region fields surge
  to the poles at the time of polar field reversal (1990-1991). The wind
  speed patterns that Ulysses encounters during its second polar orbit
  are expected to show the same general characteristics.

Title: Solar Wind Stream Interactions and the Wind Speed-Expansion
    Factor Relationship.
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.; Phillips, J. L.; Goldstein,
   B. E.
Bibcode: 1997ApJ...488L..51W
Altcode:
  Previous studies have shown that the solar wind speed observed near
  Earth is inversely correlated with the divergence rate of magnetic flux
  tubes near the Sun. We test the global validity of this relationship
  by employing Ulysses wind speed measurements during 1990-1997 as well
  as inecliptic data for 1976-1997. When the correspondence between wind
  speeds and expansion factors is adjusted to yield optimal agreement with
  the high-latitude Ulysses measurements, the model matches the overall
  patterns of fast and slow wind near the ecliptic but predicts too much
  very fast wind there. We show how this discrepancy can be resolved
  by taking account of wind stream interactions, where we apply a crude
  algorithm based on the propagation times of neighboring wind parcels;
  the interactions reduce the amount of very fast wind at latitudes
  where slow wind is present. We also test and reject an alternative
  model in which the wind speed is assumed to be a function only of
  angular distance from the heliospheric neutral sheet.

Title: Origin and Evolution of Coronal Streamer Structure During
    the 1996 Minimum Activity Phase
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.; Howard, R. A.; Kraemer,
   J. R.; Rich, N. B.; Andrews, M. D.; Brueckner, G. E.; Dere, K. P.;
   Koomen, M. J.; Korendyke, C. M.; Michels, D. J.; Moses, J. D.;
   Paswaters, S. E.; Socker, D. G.; Wang, D.; Lamy, P. L.; Llebaria,
   A.; Vibert, D.; Schwenn, R.; Simnett, G. M.
Bibcode: 1997ApJ...485..875W
Altcode:
  We employ coronal extrapolations of solar magnetograph data to interpret
  observations of the white-light streamer structure made with the LASCO
  coronagraph in 1996. The topological appearance of the streamer belt
  during the present minimum activity phase is well described by a model
  in which the Thomson-scattering electrons are concentrated around a
  single, warped current sheet encircling the Sun. Projection effects
  give rise to bright, jet-like structures or spikes whenever the current
  sheet is viewed edge-on multiple spikes are seen if the current sheet is
  sufficiently wavy. The extreme narrowness of these features in polarized
  images indicates that the scattering layer is at most a few degrees
  wide. We model the evolution of the streamer belt from 1996 April to
  1996 September and show that the effect of photospheric activity on
  the streamer belt topology depends not just on the strength of the
  erupted magnetic flux, but also on its longitudinal phase relative
  to the background field. Using flux transport simulations, we also
  demonstrate how the streamer belt would evolve during a prolonged
  absence of activity.

Title: The Green Line Corona and Its Relation to the Photospheric
    Magnetic Field
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.; Hawley, S. H.; Kraemer,
   J. R.; Brueckner, G. E.; Howard, R. A.; Korendyke, C. M.; Michels,
   D. J.; Moulton, N. E.; Socker, D. G.; Schwenn, R.
Bibcode: 1997ApJ...485..419W
Altcode:
  Images of the green line corona made with the LASCO C1 coronagraph
  on SOHO are analyzed by applying current-free extrapolations to the
  observed photospheric field. The Fe XIV λ5303 emission is shown to
  be closely related to the underlying photospheric field strength. By
  modeling the observed intensity patterns as a function of latitude and
  height above the solar limb, we derive an approximate scaling law of the
  form n<SUB>foot</SUB> ~ &lt;B<SUB>foot</SUB>&gt;<SUP>0.9</SUP>, where
  n<SUB>foot</SUB> is the density of the green line-emitting plasma and
  &lt;B<SUB>foot</SUB>&gt; is the average field strength at the footprints
  of the coronal loop. The observed high-latitude enhancements in the
  green line corona are attributed to the poleward concentration of the
  large-scale photospheric field. The strongest such enhancements occur
  where the high-latitude unipolar fields become reconnected to active
  region flux at lower latitudes; the global emission pattern rotates
  quasi-rigidly at the rate of the dominant active region complex. The
  validity of the current-free approximation is assessed by comparing
  the topology of the observed and simulated green line structures.

Title: Measurements of Flow Speeds in the Corona Between 2 and 30
    R<SUB>⊙</SUB>
Authors: Sheeley, N. R.; Wang, Y. -M.; Hawley, S. H.; Brueckner,
   G. E.; Dere, K. P.; Howard, R. A.; Koomen, M. J.; Korendyke, C. M.;
   Michels, D. J.; Paswaters, S. E.; Socker, D. G.; St. Cyr, O. C.;
   Wang, D.; Lamy, P. L.; Llebaria, A.; Schwenn, R.; Simnett, G. M.;
   Plunkett, S.; Biesecker, D. A.
Bibcode: 1997ApJ...484..472S
Altcode:
  Time-lapse sequences of white-light images, obtained during sunspot
  minimum conditions in 1996 by the Large Angle Spectrometric Coronagraph
  on the Solar and Heliospheric Observatory, give the impression of
  a continuous outflow of material in the streamer belt, as if we
  were observing Thomson scattering from inhomogeneities in the solar
  wind. Pursuing this idea, we have tracked the birth and outflow of
  50-100 of the most prominent moving coronal features and find that:
  <P />1. They originate about 3-4 R<SUB>⊙</SUB> from Sun center as
  radially elongated structures above the cusps of helmet streamers. Their
  initial sizes are about 1 R<SUB>⊙</SUB> in the radial direction and
  0.1 R<SUB>⊙</SUB> in the transverse direction. <P />2. They move
  radially outward, maintaining constant angular spans and increasing
  their lengths in rough accord with their speeds, which typically
  double from 150 km s<SUP>-1</SUP> near 5 R<SUB>⊙</SUB> to 300 km
  s<SUP>-1</SUP> near 25 R<SUB>⊙</SUB>. <P />3. Their individual speed
  profiles v(r) cluster around a nearly parabolic path characterized
  by a constant acceleration of about 4 m s<SUP>-2</SUP> through most
  of the 30 R<SUB>⊙</SUB> field of view. This profile is consistent
  with an isothermal solar wind expansion at a temperature of about
  1.1 MK and a sonic point near 5 R<SUB>⊙</SUB>. <P />Based on their
  relatively small initial sizes, low intensities, radial motions, slow
  but increasing speeds, and location in the streamer belt, we conclude
  that these moving features are passively tracing the outflow of the
  slow solar wind.

Title: Association of Extreme-Ultraviolet Imaging Telescope (EIT)
    Polar Plumes with Mixed-Polarity Magnetic Network
Authors: Wang, Y. -M.; Sheeley, N. R.; Dere, K. P.; Duffin, R. T.;
   Howard, R. A.; Michels, D. J.; Moses, J. D.; Harvey, J. W.; Branston,
   D. D.; Delaboudinière, J. -P.; Artzner, G. E.; Hochedez, J. F.;
   Defise, J. M.; Catura, R. C.; Lemen, J. R.; Gurman, J. B.; Neupert,
   W. M.; Newmark, J.; Thompson, B.; Maucherat, A.; Clette, F.
Bibcode: 1997ApJ...484L..75W
Altcode:
  SOHO EIT spectroheliograms showing the polar coronal holes during the
  present sunspot minimum are compared with National Solar Observatory
  (Kitt Peak) magnetograms taken in Fe I λ8688 and Ca II λ8542. The
  chromospheric λ8542 magnetograms, obtained on a routine, near-daily
  basis since 1996 June, reveal the Sun's strong polar fields with
  remarkable clarity. We find that the Fe IX λ171 polar plumes occur
  where minority-polarity flux is in contact with flux of the dominant
  polarity inside each polar hole. Moreover, the locations of ``plume
  haze'' coincide approximately with the patterns of brightened He
  II λ304 network within the coronal hole. The observations appear
  to be consistent with mechanisms of plume formation involving
  magnetic reconnection between unipolar flux concentrations and nearby
  bipoles. The fact that minority-polarity fields constitute only a small
  fraction of the total magnetic flux within the polar holes suggests
  that plumes are not the main source of the high-speed polar wind.

Title: Using LASCO Observations to Infer Solar Wind Flow Near the Sun
Authors: Sheeley, N. R., Jr.; Brueckner, G. E.; Dere, K. P.; Howard,
   R. A.; Korendyke, C. M.; Michels, D. J.; Socker, D. G.; Koomen, M. J.;
   Paswaters, S. E.; Wang, D.; Lamy, P. L.; Llebaria, A.; Schwenn, R.;
   St Cyr, O. C.; Simnett, G. M.; Plunkett, S.; Biesecker, D. A.
Bibcode: 1997SPD....28.0301S
Altcode: 1997BAAS...29..907S
  We have continued to track individual coronal features as they become
  detached from helmet streamers and move outward from the Sun. The
  composite speed profile for 50-100 features has a parabolic shape
  with a constant acceleration of about 4 m/s(2) over the 2-30 R field
  of view. This well-determined speed profile contrasts strongly with
  the nearly uniform scatterplot obtained for about 50 nominal coronal
  mass ejections (CMEs), and suggests that these detached bits of coronal
  ``debris'' are passively tracing the speed of the slow solar wind. We
  have also begun the more difficult task of tracking outflow along
  polar plumes and will summarize these results as of June 1997.

Title: Richard Tousey 1908-1997
Authors: Koomen, M. J.; Hunter, W. R.; Sheeley, N. R.
Bibcode: 1997CIBu..140....4K
Altcode:
  No abstract at ADS

Title: Near-Sun Magnetic Fields and the Solar Wind
Authors: Sheeley, N. R., Jr.; Wang, Y. -M.; Phillips, J. L.
Bibcode: 1997cwh..conf..459S
Altcode: 2006mslp.conf..459S
  No abstract at ADS

Title: Obituary: Robert B. Leighton, 1919-1997
Authors: Neugebauer, Gerry; Peck, Charles W.; Sheeley, Neil; Trimble,
   Virginia
Bibcode: 1997BAAS...29.1477N
Altcode:
  No abstract at ADS

Title: Obituary: Richard Tousey, 1908-1997
Authors: Koomen, M. J.; Hunter, W. R.; Sheeley, N. R., Jr.
Bibcode: 1997BAAS...29.1494K
Altcode:
  No abstract at ADS

Title: ULYSSES plasma parameters: latitudinal, radial, and temporal
    variations.
Authors: Goldstein, B. E.; Neugebauer, M.; Phillips, J. L.; Bame, S.;
   Gosling, J. T.; McComas, D.; Wang, Y. -M.; Sheeley, N. R.; Suess, S. T.
Bibcode: 1996A&A...316..296G
Altcode:
  Observations by the Ulysses SWOOPS plasma experiment are used
  to investigate spatial and temporal gradients during the mission,
  with emphasis on more recent high latitude observations including the
  recent South Pole to North Pole passage during solar minimum. Compared
  to lower latitudes, the high latitude solar wind had higher average
  speed, proton temperature, and momentum flux, and lower number flux
  density. As the average momentum flux observed in the high speed wind
  was 21% greater than at the equator, during solar minimum the distance
  to the heliopause will be comparatively less in the solar equatorial
  plane than over the poles. The long term temporal gradients of momentum
  flux over the life of the mission are considerably larger than the
  latitudinal gradient observed by Ulysses during solar minimum. A
  modest North-South high latitude asymmetry is observed in the plasma
  parameters; the velocity is on the average 13km/s to 24km/s greater at
  Northern latitudes than at Southern, and temperature is also higher. The
  North-South temperature asymmetry is greater than can be explained by
  the North-South velocity difference and the dependence of solar wind
  temperature upon speed. The power law dependence of temperature on
  heliocentric distance, r, at high latitudes is in range r^-0.81^ to
  r^-1.03^, where r^-0.81^ is the Southern latitude result and r^-1.03^
  the Northern. The parameter T/n^1/2^, where T is temperature and n
  is proton number density, can be better predicted from speed than can
  temperature alone. Comparison with calculations based on source models
  and magnetograph data indicate that the expansion of open coronal
  field lines close to the Sun was greater in the Southern hemisphere
  than in the Northern; this anticorrelation with the expansion factor
  is consistent with previous observational and theoretical work.

Title: Elemental Abundance Variations in the Solar Atmosphere
Authors: Sheeley, N. R., Jr.
Bibcode: 1996ApJ...469..423S
Altcode:
  Skylab solar images in the transition region lines of neon, magnesium,
  and calcium have been used to trace elemental abundance variations
  in sunspots and the quiet Sun. Sunspots are invariably accompanied
  by spikelike features, enriched in elements of low first ionization
  potential (FIP) such as magnesium and calcium, and extending
  outward from the penumbras. Material with the normal, unenriched,
  photospheric-like composition is sometimes seen over the umbra, but
  it is only seen in the presence of very bright chromospheric emission
  associated with flares or emerging flux. The salt-and-pepper fields
  of the quiet Sun give rise to small-scale structures, enhanced in
  the lines of both helium and neon, and having the "photospheric"
  composition. However, enrichments of low-Fl P elements are sometimes
  found at unipolar flux concentrations in coronal holes, and occasionally
  they have very large enrichment factors. These observations suggest
  that the composition depends on whether the plasma is coronal or not
  and that the fractionation process is somehow related to the production
  of coronal material.

Title: The Magnetic Nature of Coronal Holes
Authors: Wang, Yi-Ming; Hawley, Scott H.; Sheeley, Neil R., Jr.
Bibcode: 1996Sci...271..464W
Altcode:
  Solar wind streams originate from low-density, magnetically open
  regions of the sun's corona, known as coronal holes. The locations,
  areal sizes, rotation, and solar-cycle evolution of these regions
  can be reproduced and understood by applying simple extrapolation
  models to measurements of the photospheric magnetic field. The
  surprisingly rigid rotation displayed by many coronal holes suggests
  that field-line reconnection occurs continually in the corona, despite
  the high electrical conductivity of the coronal plasma. The magnetic
  field strengths and field-line divergence rates in coronal holes
  can be related empirically to the bulk speed and the mass and energy
  flux densities of the solar wind plasma. Such relations may help to
  illuminate the physical processes responsible for heating the corona
  and driving the solar wind.

Title: Coronal Plumes and Their Relationship to Network Activity
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 1995ApJ...452..457W
Altcode:
  Using Skylab extreme-ultraviolet spectroheliograms, we address the
  question of what lies under a coronal plume. Plumes and their base
  areas, both inside polar coronal holes and within lower latitude holes
  near central meridian, are identified in the Mg IX λ368 emission
  line. While some (usually spike-shaped) plumes show a strongly enhanced
  Mg IX core, others (sheetlike in appearance) are characterized by a
  much more diffuse base which may extend over several supergranules. The
  base areas are found to contain collections of compact (although not
  always intense) Ne VII λ465 features, whose locations in turn generally
  coincide with enhancements in the He II λ304 network inside the coronal
  hole. Bright plumes always show intense network features within their
  base areas, but the converse does not hold: not every Ne VII or He II
  bright point has an associated Mg IX plume. By comparing the locations
  of plumelike Mg IX "haze" in a lower latitude hole with a simultaneous
  high-resolution magnetogram, we infer that coronal plumes occur near
  regions of mixed magnetic polarity. We suggest a mechanism for plume
  formation, whereby small bipoles within a coronal hole reconnect with
  unipolar flux concentrations located at network junctions.

Title: Coronal flux-tube expansion and the polar wind
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.; Phillips, J. L.
Bibcode: 1995AdSpR..16i.365W
Altcode: 1995AdSpR..16..365W
  Empirical and theoretical studies indicate an inverse correlation
  between the areal expansion rate of magnetic flux tubes near the
  Sun and the solar wind speed far from the sun. This relationship is
  combined with solar magnetograph measurements to predict the wind
  speed structures at high latitudes, and the results are compared with
  observations now being carried out by Ulysses. Based on the evolution
  of the polar fields during previous sunspot cycles, we also discuss
  how the high-latitude wind is likely to evolve between 1994 and the
  next solar maximum. Our main predictions are as follows: (1) As the
  cycle declines, the fastest wind streams are expected to be centered
  at mid-latitudes (above the polar-hole extensions), not at the poles
  themselves. (2) The fastest wind at the poles is predicted to occur
  not at sunspot minimum, when the polar fields are strongest and large
  axisymmetric polar coronal holes are present, but just after sunspot
  maximum, when the polar fields undergo their polarity reversal.

Title: Solar Implications of ULYSSES Interplanetary Field Measurements
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 1995ApJ...447L.143W
Altcode:
  Recent observations by the Ulysses magnetometer team have shown that the
  strength of the radial interplanetary field component, |B<SUB>r</SUB>| ,
  is essentially independent of latitude, a result which implies that the
  heliospheric currents are confined entirely to thin sheets. Using such
  a current sheet model, we extrapolate the observed photospheric field to
  1 AU and compare the predicted magnitude and sign of Br with spacecraft
  measurements during 1970--1993. Approximate agreement can be obtained
  if the solar magnetograph measurements in the Fe I lambda 5250 line are
  scaled upward by a latitude-dependent factor, similar to that derived
  by Ulrich from a study of magnetic saturation effects. The correction
  factor implies sharply peaked polar fields near sunspot minimum,
  with each polar coronal hole having a mean field strength of 10 G.

Title: Comparing ULYSSES wind speed with coronal flux-tube expansion
    factor
Authors: Sheeley, N. R., Jr.; Wang, Y. -M.; Phillips, J. L.; Bame,
   S. J.; Goldstein, B. E.
Bibcode: 1995sowi.confR..63S
Altcode:
  We have been comparing measurements of solar wind speed at the
  Ulysses spacecraft with coronal flux-tube expansion rates, derived from
  photospheric field measurements using a current-free coronal model. The
  large-scale patterns of derived speed have continued to reproduce the
  observed patterns from launch through south polar passage to the present
  40S latitude of the spacecraft. The fastest non-transient wind speeds
  of approx. 860 km/s were encountered at midlatitudes en route to the
  south pole, rather than during polar passage when the peak speeds were
  approx. 820 km/s. Although this result is in qualitative agreement with
  the idea that the wind speed is controlled by the coronal flux-tube
  expansion rate, the 40 km/s difference is significantly smaller than
  the 100-150 km/s difference based on our in-ecliptic calibration. This
  paper will summarize our attempts to resolve this discrepancy and will
  show the observational status of our coronal/interplanetary comparison
  at the time of the meeting.

Title: Identification of Low-Latitude Coronal Plumes in
    Extreme-Ultraviolet Spectroheliograms
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 1995ApJ...446L..51W
Altcode:
  Using Skylab extreme ultraviolet images of the solar disk, we have
  identified plumelike features inside low-latitude coronal holes
  undergoing limb passage. Like their polar counterparts, these diffuse
  Mg IX structures are located above enhancements in the weak neon and
  helium background emission within the coronal hole. We conclude that
  coronal plumes are not unique to the polar regions but may occur in
  open magnetic regions at any latitude.

Title: Source regions of the solar wind
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 1995sowi.conf...31W
Altcode:
  Using Skylab XUV data, we examine some properties of the source regions
  of the solar wind. In particular, we discuss the physical nature of
  polar plumes and their relationship to the polar wind, the nature of
  the source regions of the slow solar wind, and the relationship between
  abundance anomalies (the FIP effect) determined from the Skylab data
  and the sources of fast and slow wind.

Title: Observations of Elemental Abundance Variations in the Solar
    Atmosphere
Authors: Sheeley, N. R.
Bibcode: 1995SPD....26..610S
Altcode: 1995BAAS...27Q.963S
  No abstract at ADS

Title: A Volcanic Origin for High-FIP Material in the Solar Atmosphere
Authors: Sheeley, N. R., Jr.
Bibcode: 1995ApJ...440..884S
Altcode:
  Photospheric magnetograms and Skylab images in the lines of Ne VI and
  Mg VI near 400 Å have been used to study the relation between magnetic
  field topology and solar composition. Although plasma with the neon-rich
  photospheric composition is rare in the corona, it always occurs where
  new flux is emerging. This suggests that the neon richness of the
  plasma reflects its recent photospheric origin, not its closed-loop
  magnetic topology as has been assumed in the past. Such a "volcanic"
  process would be consistent with our observations of sunspots, which
  have the Ne-rich composition when they lie next to a neutral line
  where flux is emerging, but have the Mg-rich composition when they
  are surrounded by a "buffer zone" of like-polarity flux.

Title: The Rotation of Photospheric Magnetic Fields: A Random Walk
    Transport Model
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 1994ApJ...430..399W
Altcode:
  In an earlier study of solar differential rotation, we showed that
  the transport of magnetic flux across latitudes acts to establish
  quasi-stationary patterns, therby accounting for the observed rigid
  rotation of the large-scale photospheric field. In that paper, the
  effect of supergranular convection was represented by a continuum
  diffusion, limiting the applicability of the calculations to large
  spatial scales. Here we extend the model to scales comparable to that
  of the supergranulation itself by replacing the diffusive transport
  with a discrete random walk process. Rotation curves are derived
  by cross-correlating the simulated photospheric field maps for a
  variety of time lags and spatial resolutions. When the lag between
  maps is relatively short less than or approximately = 15 days), the
  midlatitude correlation functions show two distinct components: a broad
  feature associated with the large-scale unipolar patterns and a narrow
  feature originating from small magnetic structures encompossing from
  one to several supergranular cells. By fitting the broad component
  we obtain the rigid rotation profile of the patterns, whereas by
  fitting the narrow component, we recover the differential rate of
  the photospheric plasma itself. For time lags of 1 month or greater,
  only the broad feature associated with the long-lived patterns remains
  clearly identifiable in the simulations.

Title: Ulysses at 50° south: constant immersion in the high-speed
    solar wind
Authors: Phillips, J. L.; Balogh, A.; Bame, S. J.; Goldstein, B. E.;
   Gosling, J. T.; Hoeksema, J. T.; McComas, D. J.; Neugebauer, M.;
   Sheeley, N. R., Jr.; Wang, Y. -M.
Bibcode: 1994GeoRL..21.1105P
Altcode:
  We present speed observations from the Ulysses solar wind plasma
  experiment through 50° south latitude. The pronounced speed modulation
  arising from solar rotation and the tilt of the heliomagnetic current
  sheet has nearly disappeared. Ulysses is now observing wind speeds
  in the 700 to 800 km s<SUP>-1</SUP> range, with a magnetic polarity
  indicating an origin in the large south polar coronal hole. The
  strong compressions, rarefactions, and shock waves previously seen have
  weakened or disappeared. Occasional coronal mass ejections characterized
  by low plasma density caused by radial expansion have been observed. The
  coronal configuration was simple and stable in 1993, indicating that
  the observed solar wind changes were caused by increasing spacecraft
  latitude. Trends in prevailing speed with increasing latitude support
  previous findings. A decrease in peak speed southward of 40° latitude
  may indicate that the fastest solar wind comes from the equatorial
  extensions of the polar coronal holes.

Title: Global evolution of interplanetary sector structure, coronal
holes, and solar wind streams during 1976-1993: Stackplot displays
    based on solar magnetic observations
Authors: Wang, Y. M.; Sheeley, N. R., Jr.
Bibcode: 1994JGR....99.6597W
Altcode:
  We use potential field calculations and solar magnetic observations
  during 1976-1993 to infer the evolution of interplanetary sector
  structure, coronal holes, and solar wind streams at heliographic
  latitudes ranging from 80°S to 80°N. The results are presented in
  the form of stackplots, which show long-lived patterns that rotate
  quasi-rigidly at rates determined by the photospheric distribution
  of nonaxisymmetric magnetic flux. The fastest wind streams and their
  coronal hole sources form slowly rotating patterns near the poles just
  after sunspot maximum but migrate to lower latitudes and tend to rotate
  at near-equatorial rates as sunspot activity declines.

Title: Returning to the random walk
Authors: Sheeley, N. R., Jr.; Wang, Y. -M.
Bibcode: 1994ASIC..433..379S
Altcode:
  No abstract at ADS

Title: Understanding the Rotation of Coronal Holes
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 1993ApJ...414..916W
Altcode:
  In an earlier study we found that the rotation of coronal holes
  could be understood on the basis of a nearly current-free coronal
  field, with the holes representing open magnetic regions. In this
  paper we illustrate the model by focusing on the case of CH1, the
  rigidly rotating boot-shaped hole observed by Skylab. We show that the
  interaction between the polar fields and the flux associated with active
  regions produces distortions in the coronal field configuration and
  thus in the polar-hole boundaries; these distortions corotate with the
  perturbing nonaxisymmetric flux. In the case of CH1, positive-polarity
  field lines in the northern hemisphere 'collided' with like-polarity
  field lines fanning out from a decaying active region complex located
  just below the equator, producing a midlatitude corridor of open field
  lines rotating at the rate of the active region complex. Sheared coronal
  holes result when nonaxisymmetric flux is present at high latitudes,
  or equivalently, when the photospheric neutral line extends to high
  latitudes. We demonstrate how a small active region, rotating at the
  local photospheric rate, can drift through a rigidly rotating hole
  like CH1. Finally, we discuss the role of field-line reconnection in
  maintaining a quasi-potential coronal configuration.

Title: Coronal Flux-Tube Expansion and the Solar Wind Speed at Ulysses
Authors: Sheeley, N. R., Jr.; Wang, Y. -M.; Bame, S. J.; Phillips,
   J. L.; Goldstein, B. E.
Bibcode: 1993BAAS...25.1203S
Altcode:
  No abstract at ADS

Title: Flux Emergence and the Evolution of Large-Scale Photosphenc
    Field Patterns (Abstract)
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 1993ASPC...46..487W
Altcode: 1993mvfs.conf..487W; 1993IAUCo.141..487W
  No abstract at ADS

Title: A New Determination of the Solar Rotation Rate
Authors: Sheeley, N. R., Jr.; Wang, Y. -M.; Nash, A. G.
Bibcode: 1992ApJ...401..378S
Altcode:
  We use 'stackplot' displays to compare observations of the photospheric
  magnetic field during sunspot cycle 21 with simulations based on the
  flux-transport model. Adopting nominal rates of diffusion, differential
  rotation, and meridional flow, we obtain slanted patterns similar
  to those of the observed field, even when the sources of flux are
  assigned random longitudes in the model. At low latitudes, the slopes
  of the nearly vertical patterns of simulated field are sensitive to
  the rotation rate used in the calculation, and insensitive to the
  rates of diffusion and flow during much of the sunspot cycle. Good
  agreement between the observed and simulated patterns requires a
  synodic equatorial rotation period of 26.75 +/- 0.05 days.

Title: Obituary: Ana Gomes Nash, 1957-1992
Authors: Sheeley, Neil R.; Wang, Yi-Ming
Bibcode: 1992BAAS...24.1329S
Altcode:
  No abstract at ADS

Title: On Potential Field Models of the Solar Corona
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 1992ApJ...392..310W
Altcode:
  It is shown that the line-of-sight matching procedure involved in
  potential field models of the solar corona do not make good use of the
  available data because there is strong evidence that the magnetic field
  is nearly radial, and therefore nonpotential, at the photosphere. It is
  argued that the observed photospheric field should first be corrected
  for line-of-sight projection and then matched to the radial component
  of the potential field. It is shown that this procedure yields much
  stronger polar fields than the standard method and produces better
  agreement with high-latitude coronal holes and with white-light
  structures in the outer corona. The relationship of both methods to
  the observed inclination angles of polar plumes is also discussed.

Title: The relationship between solar wind speed and the areal
    expansion factor
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 1992sws..coll..125W
Altcode:
  Empirical studies indicate that the solar wind speed at Earth is
  inversely correlated with the divergence rate of the coronal magnetic
  field. This result suggests that the mechanical energy flux at the
  coronal base (in the form of Alfven waves, for example) is roughly
  constant within open field regions.

Title: The Flux-Transport Model and Its Implications
Authors: Sheeley, N. R., Jr.
Bibcode: 1992ASPC...27....1S
Altcode: 1992socy.work....1S
  No abstract at ADS

Title: Coronal holes and solar wind streams during the sunspot cycle
Authors: Sheeley, N. R., Jr.
Bibcode: 1992sws..coll..263S
Altcode:
  Complementary synoptic observations of the Sun and interplanetary
  space have been obtained nearly continuously for more than two
  sunspot cycles and have led to new ideas about the origin of the
  solar wind. These observations show an inverse correlation between
  wind speed at Earth and magnetic flux tube expansion in the corona,
  with fast wind originating from slowly diverging tubes and vice
  versa. Although this result is consistent with the Skylab-era concept
  that fast wind originates from the center of a large isolated coronal
  hole, it implies that the wind may be even faster at the facing edges
  of like-polarity holes where the flux-tubes converge as they begin
  their outward extension. Thus, very fast wind ought to originate from
  the high-latitude edges of the circumpolar holes soon after sunspot
  maximum and from the mid-latitude necks of the polar-hole lobes during
  the declining phase of the cycle. The observed inverse correlation may
  be understood physically in terms of a model in which Alfven waves
  boost the wind to high speed provided that the wave energy flux is
  distributed approximately uniformly at the coronal base.

Title: A New Solar Cycle Model Including Meridional Circulation
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.; Nash, A. G.
Bibcode: 1991ApJ...383..431W
Altcode:
  A kinematic model is presented for the solar cycle which includes
  not only the transport of magnetic flux by supergranular diffusion
  and a poleward bulk flow at the sun's surface, but also the effects
  of turbulent diffusion and an equatorward 'return flow' beneath
  the surface. As in the earlier models of Babcock and Leighton, the
  rotational shearing of a subsurface poloidal field generates toroidal
  flux that erupts at the surface in the form of bipolar magnetic
  regions. However, such eruptions do not result in any net loss of
  toroidal flux from the sun (as assumed by Babcock and Leighton);
  instead, the large-scale toroidal field is destroyed both by 'unwinding'
  as the local poloidal field reverses its polarity, and by diffusion as
  the toroidal flux is transported equatorward by the subsurface flow
  and merged with its opposite hemisphere counterpart. The inclusion
  of meridional circulation allows stable oscillations of the magnetic
  field, accompanied by the equatorward progression of flux eruptions,
  to be achieved even in the absence of a radial gradient in the angular
  velocity. An illustrative case in which a subsurface flow speed of
  order 1 m/s and subsurface diffusion rate of order 10 sq km/s yield
  22-yr oscillations in qualitative agreement with observations.

Title: Out-of-ecliptic tests of the inverse correlation between
    solar wind speed and coronal expansion factor
Authors: Sheeley, N. R., Jr.; Swanson, E. T.; Wang, Y. -M.
Bibcode: 1991JGR....9613861S
Altcode:
  In this paper we address the question of whether out-of-ecliptic
  measurements satisfy the inverse correlation between wind speed at
  1 AU and flux tube divergence in the corona, already found from
  measurements in the ecliptic. Using the in-ecliptic calibration,
  we derive out-of-ecliptic speeds from coronal expansion factors
  determined from global observations of photospheric field and their
  current-free coronal extension. These derived speeds are compared with
  speeds inferred from interplanetary scintillation measurements during
  1972-1988 and with in situ speeds measured by the Pioneer 11 spacecraft
  at 16°N latitude during 1984-1988. These three sets of wind speed
  show the same overall variation with latitude and time during the
  sunspot cycle, with higher latitudes having more years of fast wind
  than lower latitudes and all latitudes having slow wind at sunspot
  maximum. Although some detailed discrepancies are also present, the
  overall agreement is comparable to that achieved in the ecliptic plane.

Title: Magnetic Flux Transport and the Sun's Dipole Moment: New
    Twists to the Babcock-Leighton Model
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 1991ApJ...375..761W
Altcode:
  The mechanisms that give rise to the sun's large-scale poloidal
  magnetic field are explored in the framework of the Babcock-Leighton
  (BL) model. It is shown that there are in general two quite distinct
  contributions to the generation of the 'alpha effect': the first is
  associated with the axial tilts of the bipolar magnetic regions as they
  erupt at the surface, while the second arises through the interaction
  between diffusion and flow as the magnetic flux is dispersed over the
  surface. The general relationship between flux transport and the BL
  dynamo is discussed.

Title: Polar Faculae: 1906--1990
Authors: Sheeley, N. R., Jr.
Bibcode: 1991ApJ...374..386S
Altcode:
  The numbers of faculae at the sun's poles have been estimated from
  white-light images obtained at the Mount Wilson Observatory during
  1970-1990 and have been combined with previous measurements extending
  back to 1906 when the observations began. The combined measurements
  now span four complete 22 year cycles and show the following: (1) the
  numbers of north and south polar faculae were about 50 percent larger
  around sunspot minimum in 1986 than in 1976, but were still smaller
  than some of the very large numbers that occurred near sunspot minima in
  earlier cycles; (2) in 1974, the number of south polar faculae exhibited
  a short-lived increase which coincided with the arrival of a surge of
  trailing-polarity flux at the pole, suggesting that similar poleward
  surges may have been responsible for previously unexplained bursts of
  faculae such as the one that occurred at the south pole in 1959; and
  (3) the numbers of polar faculae have been highly correlated with the
  Wilcox Solar Observatory polar field strengths since these magnetic
  measurements began in 1976.

Title: Why Fast Solar Wind Originates from Slowly Expanding Coronal
    Flux Tubes
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 1991ApJ...372L..45W
Altcode:
  Empirical studies indicate that the solar wind speed at earth is
  inversely correlated with the divergence rate of the coronal magnetic
  field. It is shown that this result is consistent with simple wind
  acceleration models involving Alfven waves, provided that the wave
  energy flux at the coronal base is taken to be roughly constant within
  open field regions.

Title: Deriving Solar Wind Speed from Solar Magnetic Field
    Measurements
Authors: Nash, A. G.; Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 1991BAAS...23..821N
Altcode:
  No abstract at ADS

Title: Magnetic Field Configurations Associated with Fast Solar Wind
Authors: Sheeley, N. R., Jr.; Wang, Y. -M.
Bibcode: 1991SoPh..131..165S
Altcode:
  In this paper, we consider the implications of the observed inverse
  correlation between solar wind speed at Earth and the expansion rate
  of the Sun-Earth flux tube as it passes through the corona. We find
  that the coronal expansion rate depends critically on the large-scale
  photospheric field distribution around the footpoint of the flux tube,
  with the smallest expansions occurring in tubes that are rooted near
  a local minimum in the field. This suggests that the fastest wind
  streams originate from regions where large coronal holes are about to
  break apart and from the facing edges of adjacent like-polarity holes,
  whose field lines converge as they transit the corona. These ideas
  lead to the following predictions: Weak holes and fragmentary holes
  can be sources of very fast wind.

Title: Photospheric and coronal magnetic fields
Authors: Sheeley, N. R., Jr.
Bibcode: 1991RvGeo..29S.925S
Altcode: 1991RvGeS..29..925S; 1991RvGeo..29..925S
  Research on small-scale and large-scale photospheric and coronal
  magnetic fields during 1987-1990 is reviewed, focusing on observational
  studies. Particular attention is given to the new techniques, which
  include the correlation tracking of granules, the use of highly
  Zeeman-sensitive infrared spectral lines and multiple lines to deduce
  small-scale field strength, the application of long integration
  times coupled with good seeing conditions to study weak fields,
  and the use of high-resolution CCD detectors together with computer
  image-processing techniques to obtain images with unsurpassed spatial
  resolution. Synoptic observations of large-scale fields during the
  sunspot cycle are also discussed.

Title: The solar activity cycle.
Authors: Rabin, Douglas M.; DeVore, C. R.; Sheeley, Neil R., Jr.;
   Harvey, Karen L.; Hoeksema, J. T.
Bibcode: 1991sia..book..781R
Altcode:
  Study of the solar cycle is entering a new era dominated by objective,
  precise measurements of magnetic, velocity and radiation fields over the
  surface of the Sun. This review emphasizes observations of photospheric
  magnetic flux during cycle 21 (1976 - 1986) and how these measurements
  have been used to model the cyclic variability of the heliospheric
  magnetic field. Indices of solar activity are discussed in terms of
  their potential to figure in theoretical or empirical models. Other
  recent data, such as measurements of large-scale surface flows and
  information on the Sun's internal rotation from helioseismology, as
  well as the magnetic flux observations, are considered in the context
  of Babcock's phenomenological model of the solar cycle: can this model
  still serve? Is there anything better to replace it?

Title: Magnetic Flux Transport and the Sunspot-Cycle Evolution of
    Coronal Holes and Their Wind Streams
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 1990ApJ...365..372W
Altcode:
  The relationships between magnetic flux transport from active regions
  and the formation and evolution of coronal holes are examined through
  numerical simulations. The model utilized is based on the assumption
  that coronal holes represent open field regions, and that the solar-wind
  speed at 1 AU is universely correlated with the divergence rate of the
  coronal field. The evolution of coronal holes and wind streams during
  1980 - 1990 is discussed, along with flux transport and the evolution
  of open field regions, and focus is placed on declining, rising, and
  maximum phases. It is concluded that supergranular diffusion spreads
  active region flux over the solar surface and wipes out pockets of
  mixed polarity, thus creating unipolar areas containing open field
  lines; differential rotation spreads flux in longitude and it combines
  with diffusion to create axisymmetric polar holes from the original
  active-region fields; and meridional flow accelerates the decay of
  low-latitude holes by carrying flux to midlatitudes.

Title: Latitudinal distribution of solar-wind speed from magnetic
    observations of the Sun
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.; Nash, A. G.
Bibcode: 1990Natur.347..439W
Altcode:
  Empirical studies suggest a close relationship between the solar-wind
  speed near the Earth and the magnetic structure of the solar corona. The
  correlation can be used to infer the latitudinal distribution of wind
  speed at different phases of the sunspot cycle, and to identify the
  sources of fast, high-latitude wind streams such as those that might
  be encountered by the Ulysses spacecraft on its journey toward the
  solar poles during 1992-1995.

Title: Solar Wind Speed and Coronal Flux-Tube Expansion
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 1990ApJ...355..726W
Altcode:
  The hypothesis that the solar wind speed at 1 AU and the rate of
  magnetic flux-tube expansion in the corona are inversely correlated
  is shown to be consistent with observations extending over the last
  22 years. This empirical relationship allows the daily wind speeds
  at earth to be predicted from a current-free extrapolation of the
  observed photospheric field into the corona. The narrow boundaries
  of high-speed wind streams are attributed to steep gradients in
  the flux-tube expansion rates at the edges of coronal holes. When a
  heliospheric current sheet is included in the model, it is found that
  the flux tubes near the hole axis, although diverging more slowly
  than those near the hole boundary in the corona, have undergone the
  greatest net expansion at 1 AU, an effect consistent with the low
  densities within high-speed streams.

Title: Coronal Mass Ejections and the Injection Profiles of Solar
    Energetic Particle Events
Authors: Kahler, S. W.; Reames, D. V.; Sheeley, N. R., Jr.
Bibcode: 1990ICRC....5..183K
Altcode: 1989ICRC....5..183K; 1990ICRC...21e.183K
  Previous studies using Skylab and Solwind coronagraph observations have
  shown that almost all E greater than 10 MeV solar energetic proton (SEP)
  events are associated with the occurrence of a coronal mass ejection
  (CME). These earlier studies did not address the relationship between
  the position of the associated CME and the timing of the injection
  of particles into the interplanetary medium. Ten cases are selected
  in which a SEP event observed with the GSFC detectors on the IMP 8 or
  ISEE 3 spacecraft was correlated to a CME well observed by the Solwind
  coronagraph. The height of the leading edge of the CME is compared with
  the particle injection profiles for several energy ranges using the
  solar release times for the particles. The derived injection profiles
  are found to be increasing and sometimes reaching maximum while the
  associated CMEs are at heights of 2-10 Ro.

Title: Evolution of the Sun's Polar Fields during Sunspot Cycle 21:
    Poleward Surges and Long-Term Behavior
Authors: Wang, Y. -M.; Nash, A. G.; Sheeley, N. R., Jr.
Bibcode: 1989ApJ...347..529W
Altcode:
  Longitudinally averaged observations of the photospheric field during
  1976-1986 are analyzed using a flux transport model. The way in
  which source eruptions, supergranular diffusion, and meridional flow
  collaborate to produce strong, highly concentrated polar fields near
  sunspot minimum is clarified as follows: (1) widespread eruptions
  of individual bipolar magnetic regions, with their leading polarity
  flux equatorward of their trailing polarity flux, collectively
  establish a large-scale separation of polarities in latitude; (2) the
  low-latitude, leading polarity flux diffuses across the equator and
  merges with its opposite hemisphere counterpart; and (3) meridional
  flow carries the resulting surplus of trailing polarity flux to
  the poles, and concentrates it there against the spreading effect
  of diffusion. Episodic 'surges' of flux to the poles are induced
  by fluctuations in the source eruption rate. Simulations indicate
  that relatively weak, trailing polarity surges may occur even in a
  steady flow field. However, in order to account for the giant surges
  of alternating polarity and the resulting oscillations in the polar
  field strength observed during 1980-1982, both accelerated flow and
  enhanced eruption rates are required.

Title: Two Eruptive Prominences and a CME on 1982FEB9
Authors: Wang, J. L.; Nelson, G. J.; Sheeley, N. R., Jr.; Howard,
   R. A.; Koomen, M. J.; Michels, D. J.; Kawabata, K.; Ogawa, H.
Bibcode: 1989AcApS...9..260W
Altcode: 1989AcApS...9..265W
  No abstract at ADS

Title: The Effect of Newly Erupting Flux on the Polar Coronal Holes
Authors: Sheeley, N. R.; Wang, Y. -M.; Harvey, J. W.
Bibcode: 1989SoPh..119..323S
Altcode:
  He I 10830 Å images show that early in sunspot cycles 21 and 22,
  large bipolar magnetic regions strongly affected the boundaries of the
  nearby polar coronal holes. East of each eruption, the hole boundary
  immediately contracted poleward, leaving a band of enhanced helium
  network. West of the eruption, the boundary remained diffuse and
  gradually expanded equatorward into the leading, like-polarity part of
  the bipolar magnetic region. Comparisons between these observations
  and simulations based on a current-free coronal model suggest that:
  The Sun's polar magnetic fields are confined to relatively small caps of
  high average field strength, apparently by a poleward meridional flow.

Title: Coronal Mass Ejections and Associated X-Ray Flare Durations
Authors: Kahler, S. W.; Sheeley, N. R., Jr.; Liggett, M.
Bibcode: 1989ApJ...344.1026K
Altcode:
  It is found that 22 percent of a sample of M1 or greater impulsive
  soft X-ray flares were associated with coronal mass ejections (CMEs)
  observed in the Solwind coronagraph. These flares were more energetic
  than similar impulsive flares without CMEs, and the associated CMEs were
  narrow (5-40 deg) in angular width. A survey of all CMEs associated
  with M1 or greater X-ray flares reveals a good correlation between
  flare duration CME angular width. The H-alpha characteristics of
  impulsive, CME-associated flares suggest that they are not the dynamic
  or eruptive flares presumed to be associated with CMEs, but rather,
  are confined flares. The H-alpha flare locations are neither centered
  under the CME legs. The disparity in size scales between the CMEs and
  their associated flares leaves the basis of the correlation between
  CME width and X-ray flare duration unresolved.

Title: Magnetic Flux Transport on the Sun
Authors: Wang, Y. -M.; Nash, A. G.; Sheeley, N. R., Jr.
Bibcode: 1989Sci...245..712W
Altcode:
  Although most of the magnetic flux observed on the sun originates in
  the low-latitude sunspot belts, this flux is gradually dispersed over
  a much wider range of latitudes by supergranular convective motions
  and meridional circulation. Numerical simulations show how these
  transport processes interact over the 11-year sunspot cycle to produce
  a strong ``topknot'' polar field, whose existence near sunspot minimum
  is suggested by the observed strength of the interplanetary magnetic
  field and by the observed areal extent of polar coronal holes. The
  required rates of diffusion and flow are consistent with the decay
  rates of active regions and with the rotational properties of the
  large-scale solar magnetic field.

Title: Average Properties of Bipolar Magnetic Regions during Sunspot
    CYCLE-21
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 1989SoPh..124...81W
Altcode:
  We examine the statistical properties of some 2700 bipolar magnetic
  regions (BMRs) with magnetic fluxes ≥3 × 10<SUP>20</SUP> Mx which
  erupted during 1976-1986. Empirical rules were used to estimate
  the fluxes visually from daily magnetograms obtained at the National
  Solar Observatory/Kitt Peak. Our analysis shows the following: (i) the
  average flux per BMR declined between 1977 and 1985; (ii) the average
  tilts of BMRs relative to the east-west line increase toward higher
  latitudes; (iii) weaker BMRs had larger root-mean-square tilt angles
  than stronger BMRs at all latitudes; (iv) over the interval 1976-1986,
  BMRs with their leading poles equatorward of their trailing poles
  contributed a total of 4 times as much flux as BMRs with `inverted'
  tilts, but the relative amount of flux contributed by BMRs with
  inverted or zero tilts increased as the sunspot cycle progressed;
  (v) only 4% of BMRs had `reversed' east-west polarity orientations;
  (vi) although the northern hemisphere produced far more flux during
  the rising phase of the sunspot cycle, the southern hemisphere largely
  compensated for this imbalance during the declining phase; (vii)
  southern-hemisphere BMRs erupted at systematically higher latitudes
  than northern-hemisphere ones through most of sunspot cycle 21.

Title: Implications of a Strongly Peaked Polar Magnetic Field
Authors: Sheeley, N. R., Jr.; Wang, Y. -M.; DeVore, C. R.
Bibcode: 1989SoPh..124....1S
Altcode:
  Using the flux-transport equation in the absence of sources, we study
  the relation between a highly peaked polar magnetic field and the
  poleward meridional flow that concentrates it. If the maximum flow
  speed ν<SUB>m</SUB> greatly exceeds the effective diffusion speed
  κ/R, then the field has a quasi-equilibrium configuration in which the
  poleward convection of flux via meridional flow approximately balances
  the equatorward spreading via supergranular diffusion. In this case,
  the flow speed ν(θ) and the magnetic field B(θ) are related by
  the steady-state approximation ν(θ) ≃ (κ/R)B'(θ)/B(θ) over
  a wide range of colatitudes θ from the poles to midlatitudes. In
  particular, a general flow profile of the form sin<SUP>p</SUP>θ
  cos<SUP>q</SUP>θ which peaks near the equator (q ≪ p) will correspond
  to a cos<SUP>n</SUP>θ magnetic field at high latitudes only if p =
  1 and ν<SUB>m</SUB> = n κ/R. Recent measurements of n ∼ 8 and κ
  ∼ 600 km<SUP>2</SUP> s<SUP>−1</SUP> would then give ν<SUB>m</SUB>
  ∼ 7 m s<SUP>−1</SUP>.

Title: The Evolution of the Sun's Polar Magnetic Field
Authors: Sheeley, N. R., Jr.; Wang, Y. -M.; Nash, A. G.
Bibcode: 1989BAAS...21..827S
Altcode:
  No abstract at ADS

Title: Average Magnetic Properties of Active Regions during Sunspot
    Cycle 21
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 1989BAAS...21Q.827W
Altcode:
  No abstract at ADS

Title: Giant solar arches and coronal mass ejections in November 1980
Authors: Svestka, Zdenek F.; Jackson, Bernard V.; Howard, Russell A.;
   Sheeley, Neil R., Jr.
Bibcode: 1989SoPh..122..131S
Altcode:
  Using data from the SOLWIND coronagraph and photometers aboard
  HELIOS-A we examine coronal mass ejections from an active region
  which produced a series of giant post-flare coronal arches. HXIS
  X-ray observations reveal that in several cases underlying flares
  did not disrupt these arch structures, but simply revived them,
  enhancing their temperature, density and brightness. Thus we are
  curious to know how these quasi-stationary X-ray structures could
  survive in the corona in spite of recurrent appearances of powerful
  dynamic flares below them. We have found reliable evidence that two
  dynamic flares which clearly revived the preexisting giant arch were
  not associated with any mass ejection. After two other flares, which
  were associated with mass ejections, the arch might have been newly
  formed when the ejection was over. In one of these cases, however,
  the arch had typical characteristics of a revived structure so that
  it is likely that it survived a powerful mass ejection nearby. In a
  magnetic configuration of the arch which results from potential-field
  modelling (Figure 1(b)) such a survival seems possible.

Title: Coronal mass ejections and coronal structures.
Authors: Hildner, E.; Bassi, J.; Bougeret, J. L.; Duncan, R. A.;
   Gary, D. E.; Gergely, T. E.; Harrison, R. A.; Howard, R. A.; Illing,
   R. M. E.; Jackson, B. V.; Kahler, S. W.; Kopp, K.; Low, B. C.; Lantos,
   P.; Phillips, K. J. H.; Poletto, G.; Sheeley, N. R., Jr.; Stewart,
   R. T.; Svestka, Z.; Waggett, P. W.; Wu, S. T.
Bibcode: 1989epos.conf..493H
Altcode:
  The work of this team was concerned with modelling of post-flare arches,
  the reconnection theory of flares, the slow variation of coronal
  structure, and the coronal and interplanetary detection, evolution,
  and consequences of mass ejections.

Title: The solar origin of long-term variations of the interplanetary
    magnetic field strength
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 1988JGR....9311227W
Altcode:
  Spacecraft measurements over the past two sunspot cycles have shown
  that the average strength of the interplanetary magnetic field (IMF)
  undergoes surprisingly modest long-term variation, unlike the total
  magnetic flux observed on the Sun. Our attempt to model the IMF during
  sunspot cycle 21, based on a current-free extrapolation of the observed
  photospheric field out to a fixed source surface where the field lines
  become radial, yields calculated IMF intensities which vary by an order
  of magnitude and which are far too low near sunspot minimum. We obtain
  much better agreement with a model containing both heliospheric sheet
  currents, which deflect polar flux toward the ecliptic, and volume
  currents, which maintain a residual latitudinal gradient in the IMF
  intensity. In order to match the observed IMF intensity levels, however,
  the measured photospheric fields had to be scaled up by approximately a
  factor of 2. Our composite model has the following main consequences:
  (1) The source of the radial component of the IMF may be represented
  to a first approximation by the dipole component of the photospheric
  field. (2) The radial IMF intensity is strongest in the direction of
  the dipole axis, which is aligned with the Sun's rotation axis near
  sunspot minimum but tilts toward the ecliptic near sunspot maximum. (3)
  The average strength of the photospheric field above latitude 55° is
  of order 10 G around sunspot minimum.

Title: Mechanisms for the Rigid Rotation of Coronal Holes
Authors: Nash, A. G.; Sheeley, N. R., Jr.; Wang, Y. -M.
Bibcode: 1988SoPh..117..359N
Altcode:
  We show that the rotation of coronal holes can be understood in
  terms of a current-free model of the coronal magnetic field, in which
  holes are the footpoint locations of open field lines. The coronal
  field is determined as a function of time by matching its radial
  component to the photospheric flux distribution, whose evolution is
  simulated including differential rotation, supergranular diffusion,
  and meridional flow. We find that ongoing field-line reconnection allows
  the holes to rotate quasi-rigidly with their outer-coronal extensions,
  until their boundaries become constrained by the neutral line of
  the photospheric field as it winds up to form stripes of alternating
  magnetic polarity. This wind-up may be significantly retarded by a
  strong axisymmetric field component which forces the neutral line to
  low latitudes; it is also gradually halted by the cross-latitudinal
  transport of flux via supergranular diffusion and a poleward bulk
  flow. We conclude that a strong axisymmetric field component is
  responsible for the prolonged rigid rotation of large meridional holes
  during the declining phase of the sunspot cycle, but that diffusion and
  flow determine the less rigid rotation observed near sunspot maximum,
  when the holes corotate with their confining polarity stripes.

Title: The Quasi-rigid Rotation of Coronal Magnetic Fields
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.; Nash, A. G.; Shampine,
   L. R.
Bibcode: 1988ApJ...327..427W
Altcode:
  Assuming that the coronal magnetic field can be approximated by
  a current-free extension of the photospheric field, the authors
  use spherical harmonic analysis and numerical simulations to
  study its rotational properties. In the outer corona, they find
  that the rotation rate is determined by three principal factors:
  1. "Coronal filtering". 2. Global averages of the photospheric
  rotation rate. 3. Ongoing source eruptions. These principles allow
  to understand the observationally inferred rotational properties of
  the outer coronal field. The overall rigidity of the rotation profile
  reflects the tendency for the photosphere's non-axisymmetric flux to
  be concentrated toward lower latitudes, where the rotational shear
  is small; increased curvature and asymmetry occur during the rising
  phase of the sunspot cycle because of the presence of higher latitude
  flux. The coronal rotation rate shows a progressive acceleration due
  to the equatorward migration of sunspots.

Title: A Model for Long-Term Variation of Interplanetary Magnetic
    Field-Strenght
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.
Bibcode: 1988BAAS...20..705W
Altcode:
  No abstract at ADS

Title: Two eruptive prominences and a CME on February 9, 1982.
Authors: Wang, J. L.; Nelson, G. J.; Sheeley, N. R., Jr.; Howard,
   R. A.; Koomen, M. J.; Michels, D. J.; Kawabata, K.; Ogawa, H.
Bibcode: 1988sscd.conf..547W
Altcode:
  Two H-alpha eruptive prominences located at N<SUB>10</SUB>W<SUB>90</SUB>
  and S<SUB>14</SUB>W<SUB>90</SUB>, respectively, were observed
  simultaneously on 9 February 1982. A CME corresponding to the northern
  one was observed by the satellite P<SUB>78-1</SUB>. No CME was seen
  for the much larger southern prominence which was associated with an
  intense radio burst. A comparison of the two eruptive prominences shows
  that the shape of a eruptive prominence and its change with time could
  be an important factor in its association with a CME.

Title: Energetic interpanetary shocks, radio emission, and coronal
    mass ejections
Authors: Cane, H. V.; Sheeley, N. R., Jr.; Howard, R. A.
Bibcode: 1987JGR....92.9869C
Altcode:
  The interplanetary shocks which generate detectable low-frequency
  (&lt;1 MHz) radio emission, represent as a group, the most energetic
  shocks produced by the sun. For all interplanetary (IP) shocks which
  generated so-called IP type II events, we find when observations were
  available, that the associated solar events involved fast (&gt;500 km/s)
  coronal mass ejections (CMEs). In comparison with the set of all CMEs
  detected by the Solwind coronagraph the CMEs associated with IP type
  II events are the most massive and energetic. The majority (&gt;50%)
  belong to the structural classes described by the Solwind researchers
  as ``curved front'' or ``halo.'' Evidence presented suggest that these
  are the same class viewed from a different persective. Our results are
  consistent with there being a close relationship between interplanetary
  shocks and fast CMEs.

Title: Sunspot - Cycle Variations of the Interplanetary Field
Strength: Implications for Coronal Models
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.; DeVore, C. R.
Bibcode: 1987BAAS...19.1133W
Altcode:
  No abstract at ADS

Title: A Mechanism for the Rigid Rotation of Coronal Holes
Authors: Nash, A. G.; Sheeley, N. R., Jr.; Wang, Y. -M.
Bibcode: 1987BAAS...19.1133N
Altcode:
  No abstract at ADS

Title: Solar activity and heliosphere-wide cosmic ray modulation
    in mid-1982
Authors: Cliver, E. W.; Mihalov, J. D.; Sheeley, N. R., Jr.; Howard,
   R. A.; Koomen, M. J.; Schwenn, R.
Bibcode: 1987JGR....92.8487C
Altcode:
  A major episode of flare activity in June and July 1982 was accompanied
  by a pair of heliosphere-wide cosmic ray modulation events. In each
  case, a large Forbush decrease (FD) at earth was followed in turn
  by apparently related decreases at Pioneer 11 (P11) and Pioneer 10
  (P10). The Pioneer spacecraft were separated by ~155° in ecliptic
  longitude. We reviewed white light coronagraph and near-sun (&lt;=1 AU)
  satellite data to identify plausible solar origins of these modulation
  events. The first widespread intensity decrease (FD 1) can be attributed
  to the combined effects of a backside flare on June 3 from solar active
  region 18382/18383, located 23° in ecliptic longitude from Pioneer 10,
  and a visible disk flare from 18405 on June 6, when this region was
  9° from Pioneer 11. The second widespread modulation event during this
  period (FD 2) may be linked to flares from active region 18474 on July
  12 and 22. The July 12 flare was located 34° in azimuth from Pioneer
  11, and the July 22 flare was 24° from Pioneer 10. Since even fast
  shocks would take ~1 month to propagate to Pioneer 11 (12 AU) and ~2
  months to reach Pioneer 10 (28 AU) in mid-1982, these ``one-to-one''
  associations must be regarded with caution. The processes of entrainment
  and coalescence can cause a given traveling interplanetary disturbance
  to lose its identify enroute to the outer heliosphere. The fact that
  we were able to identify plausible solar flare candidates for each of
  the four Forbushlike decreases observed at the Pioneer satellites (two
  each at P10 and P11), however, removes the need to invoke a chock from
  a single flare as the sole cause of either FD 1 (at both P10 and P11)
  or FD 2. Such single-flare scenarios have recently been suggested by
  several investigators to account for the widespread intensity decreases
  in mid-1982. Instead, the heliosphere-wide modulation during this
  period appears to result primarily from a sustained episode of powerful
  flares from a relatively narrow range of active solar longitude. <P />A
  significant fraction (1/2 to 3/4) of the major coronal mass ejections
  (CMEs) and near-sun shocks observed during June and July 1982 originated
  in flares occurring in a 45° band of Carrington longitude. Because
  of solar rotation these flares occur over the full range of ecliptic
  longitude and can generate an outward propagating shell of CMEs and
  shocks that encompasses the sun to produce the observed azimuthal
  symmetry in the cosmic ray modulation. The prolonged high-speed wind
  stream at P10 in the second half of 1982 may have resulted, at least
  in part, from the coalescence of a series of fast transient streams
  directed toward that distant spacecraft into an extended compound
  stream.

Title: The Origin of Rigidly Rotating Magnetic Field Patterns on
    the Sun
Authors: Sheeley, N. R., Jr.; Nash, A. G.; Wang, Y. -M.
Bibcode: 1987ApJ...319..481S
Altcode:
  Using analytical calculations and numerical simulations, it is shown
  that a meridional component of magnetic-flux transport will offset
  the shearing effect of differential rotation and give rise to rigidly
  rotating patterns of large-scale magnetic field. The nonaxisymmetric
  field attains a striped polarity pattern which rotates rigidly like a
  barber pole while its individual small-scale flux elements rotate at
  the differential rate of the latitudes they are crossing. On the sun,
  the meridional transport is provided by supergranular diffusion possibly
  assisted by a small poleward flow. New sources of flux retard this
  process and exclude the rigid rotation from the sunspot belts until
  well into the declining phase of the sunspot cycle. This mechanism
  accounts for a number of heretofore unexplained phenomena including
  the tendency for coronal holes to rotate rigidly during the declining
  phase of the sunspot cycle.

Title: The Origin of Rigidly Rotating Solar Magnetic Field Patterns
Authors: Nash, A. G.; Sheeley, N. R., Jr.; Wang, Y. -M.
Bibcode: 1987BAAS...19..938N
Altcode:
  No abstract at ADS

Title: Rotation of Coronal Holes during Sunspot Cycle 21
Authors: Harvey, J.; Sheeley, N. R., Jr.
Bibcode: 1987BAAS...19Q.935H
Altcode:
  No abstract at ADS

Title: The Quasi-Rigid Rotation of Coronal Magnetic Fields
Authors: Wang, Y. -M.; Sheeley, N. R., Jr.; Nash, A. G.; Shampine,
   L. R.
Bibcode: 1987BAAS...19..939W
Altcode:
  No abstract at ADS

Title: Simulations of the Sun's Polar Magnetic Fields during Sunspot
    CYCLE-21
Authors: DeVore, C. Richard; Sheeley, Neil R., Jr.
Bibcode: 1987SoPh..108...47D
Altcode:
  Regarding new bipolar magnetic regions as sources of flux,
  we have simulated the evolution of the radial component of the
  solar photospheric magnetic field during 1976-1984 and derived the
  corresponding evolution of the line-of-sight polar fields as seen from
  Earth. The observed timing and strength of the polar-field reversal
  during cycle 21 can be accounted for by supergranular diffusion alone,
  for a diffusion coefficient of 800 km<SUP>2</SUP> s<SUP>-1</SUP>. For
  an assumed 300 km<SUP>2</SUP> s<SUP>-1</SUP> rate of diffusion, on the
  other hand, a poleward meridional flow with a moderately broad profile
  and a peak speed of 10 m s<SUP>-1</SUP> reached at about 5° latitude
  is required to obtain agreement between the simulated and observed
  fields. Such a flow accelerates the transport of following-polarity flux
  to the polar caps, but also inhibits the diffusion of leading-polarity
  flux across the equator. For flows faster than about 10 m s<SUP>-1</SUP>
  the latter effect dominates, and the simulated polar fields reverse
  increasingly later and more weakly than the observed fields.

Title: Interpreting Coronal Evolution in Terms of the Eruption and
    Transport of Photospheric Magnetic Fields
Authors: Sheeley, N. R., Jr.; Wang, Y. -M.; Nash, A. G.; Shampine,
   L. R.
Bibcode: 1987sowi.conf..322S
Altcode:
  No abstract at ADS

Title: The Correlation of CME Angular Sizes and Soft X-Ray Time
    Scales of Solar Eruptive Events
Authors: Kahler, S. W.; Sheeley, N. R., Jr.; Howard, R. A.
Bibcode: 1987sowi.conf..232K
Altcode:
  No abstract at ADS

Title: Solar Energetic Proton Events and Coronal Mass Ejections Near
    Solar Minimum
Authors: Kahler, S. W.; Cliver, E. W.; Cane, H. V.; McGuire, R. E.;
   Reames, D. V.; Sheeley, N. R., Jr.; Howard, R. A.
Bibcode: 1987ICRC....3..121K
Altcode: 1987ICRC...20c.121K; 1987ICRC....3..121C
  No abstract at ADS

Title: Interplanetary Effects of Coronal Mass Ejections
Authors: Hildner, E.; Bassi, J.; Bougeret, J. L.; Duncan, R. A.;
   Gary, D. E.; Gergely, T. E.; Harrison, R. A.; Howard, R. A.; Illing,
   R. M. E.; Jackson, B. V.; Kahler, S. W.; Kopp, K.; Low, B. C.; Lantos,
   P.; Phillips, K. J. H.; Poletto, G.; Sheeley, N. R., Jr.; Steward,
   R. T.; Svestka, Z.; Waggett, P. W.; Wu, S. T.
Bibcode: 1986epos.conf.6.52H
Altcode: 1986epos.confF..52H
  No abstract at ADS

Title: Interplanetary shocks preceded by solar filament eruptions
Authors: Cane, H. V.; Kahler, S. W.; Sheeley, N. R., Jr.
Bibcode: 1986JGR....9113321C
Altcode:
  We discuss the solar and interplanetary characteristics of six
  interplanetary shock and energetic particle events associated with
  the eruptions of solar filaments lying outside active regions. The
  events are characterized by the familiar double-ribbon Hα brightenings
  observed with large flares, but only very weak soft X ray and microwave
  bursts. Both impulsive phases and metric type II bursts are absent in
  all six events. The energetic particles observed near the earth appear
  to be accelerated predominantly in the interplanetary shocks. The
  interplanetary shock speeds are lower and the longitudinal extents
  considerably less than those of flare-associated shocks. Three of the
  events were associated with unusual enhancements of singly ionized
  helium in the solar wind following the shocks. These enhancements
  appear to be direct detections of the cool filament material expelled
  from the corona. We suggest that these events are part of a spectrum
  of solar eruptive events which include both weaker events and large
  flares. Despite their unimpressive and unreported solar signatures,
  the quiescent filament eruptions can result in substantial space and
  geophysical disturbances.

Title: Initiations of Coronal Mass Ejections
Authors: Hildner, E.; Bassi, J.; Bougeret, J. L.; Duncan, R. A.;
   Gary, D. E.; Gergely, T. E.; Harrison, R. A.; Howard, R. A.; Illing,
   R. M. E.; Jackson, B. V.; Kahler, S. W.; Kopp, K.; Low, B. C.; Lantos,
   P.; Phillips, K. J. H.; Poletto, G.; Sheeley, N. R., Jr.; Steward,
   R. T.; Svestka, Z.; Waggett, P. W.; Wu, S. T.
Bibcode: 1986epos.conf.6.27H
Altcode: 1986epos.confF..27H
  No abstract at ADS

Title: The Slowly Varying Corona Near Solar Activity Maximum
Authors: Hildner, E.; Bassi, J.; Bougeret, J. L.; Duncan, R. A.;
   Gary, D. E.; Gergely, T. E.; Harrison, R. A.; Howard, R. A.; Illing,
   R. M. E.; Jackson, B. V.; Kahler, S. W.; Kopp, K.; Low, B. C.; Lantos,
   P.; Phillips, K. J. H.; Poletto, G.; Sheeley, N. R., Jr.; Steward,
   R. T.; Svestka, Z.; Waggett, P. W.; Wu, S. T.
Bibcode: 1986epos.conf.6.57H
Altcode: 1986epos.confF..57H
  No abstract at ADS

Title: Modelling of Coronal Mass Ejections and POST Flare Arches
Authors: Hildner, E.; Bassi, J.; Bougeret, J. L.; Duncan, R. A.;
   Gary, D. E.; Gergely, T. E.; Harrison, R. A.; Howard, R. A.; Illing,
   R. M. E.; Jackson, B. V.; Kahler, S. W.; Kopp, K.; Low, B. C.; Lantos,
   P.; Phillips, K. J. H.; Poletto, G.; Sheeley, N. R., Jr.; Steward,
   R. T.; Svestka, Z.; Waggett, P. W.; Wu, S. T.
Bibcode: 1986epos.conf6.366H
Altcode: 1986epos.confF.366H
  No abstract at ADS

Title: Simulations of the Gross Solar Magnetic Field during
    SUNSPOT-CYCLE-21
Authors: Sheeley, Neil R., Jr.; DeVore, C. Richard; Shampine, Lauree R.
Bibcode: 1986SoPh..106..251S
Altcode:
  Regarding new bipolar magnetic regions as sources of flux, we
  have simulated the evolution of the radial component of the solar
  photospheric magnetic field during 1976-1984 with a spatial resolution
  of about 34 000 km, and have derived the corresponding evolution of
  its absolute value averaged over the visible disk. For nominal values
  of the transport parameters, this simulated gross field is in close,
  though imperfect, agreement with the observed gross field and its
  associated indices of solar activity. By analyzing the response of the
  simulated gross field to variations in the transport parameters and the
  source properties, we find that the simulated field originates in newly
  erupted bipolar regions. The lifetimes of these regions are almost
  always less than 3 mo. Consequently, the strength of the simulated
  gross field is a measure of the current level of solar activity, and
  any recurrent patterns with lifetimes in excess of 6 mo must reflect
  the continuing eruption of new flux at `active longitudes' rather than
  the persistence of old flux in long-lived magnetic structures.

Title: Solar Gradual Hard X-Ray Bursts and Associated Phenomena
Authors: Cliver, E. W.; Dennis, B. R.; Kiplinger, A. L.; Kane, S. R.;
   Neidig, D. F.; Sheeley, N. R., Jr.; Koomen, M. J.
Bibcode: 1986ApJ...305..920C
Altcode:
  White-light coronagraph, H-alpha and radio data are presented as well
  as hard X-ray data for a sample of 10 gradual hard X-ray bursts (GHBs)
  in an attempt to better understand the nature of these events. It is
  found that: (1) the hard X-ray photon energy spectrum began to harden
  near the onset of the GHBs and continued in this fashion during the
  decay phase; (2) a coronal mass ejection (CME) occurred in association
  with at least nine of the GHBs; (3) the GHBs occurred in the late phase
  of major flares; (4) the centimeter wavelength bursts associated with
  the GHBs had relatively low frequency spectral maxima, and in relation
  to the observed hard X-ray emission, they were microwave-rich; (5) the
  associated decimetric bursts showed significant intensity variations
  on time scales ranging from 0.1 to approximately greater than 1 minute;
  and (6) the GHBs were most strongly associated with type IV events. It
  is concluded that the acceleration and trapping of radiating electrons
  occurs in the postflare loop systems following CMEs.

Title: Comet 1983 XX (Solwind 6)
Authors: Howard, R.; Koomen, M.; Michels, D.; Sheeley, N.; Marsden,
   B. G.
Bibcode: 1986IAUC.4229....1H
Altcode:
  R. Howard, M. Koomen, D. Michels and N. Sheeley, Naval Research
  Laboratory, report identification of another comet in the SOLWIND
  coronagraph data. The apparent heliocentric separation F (solar radii)
  and position angle O (counted from the solar north pole) have been
  converted to R.A. and Decl. by the undersigned. On the sixth data
  frame the coma was behind the occulting disk. 1983 UT F O R.A. (1950.0)
  Decl. Sept. 24.863 8.1 230.5 11 54.4 - 0 50 24.870 7.8 230.4 11 54.8
  - 0 49 24.878 7.6 231.2 11 55.0 - 0 47 24.885 7.3 230.6 11 55.3 - 0
  47 24.892 7.2 230.5 11 55.5 - 0 47 25.062 &lt; 2.5 231.8 (12 00.9 -
  0 32) Preliminary examination of the raw data suggests that SOLWIND
  6 was brighter than SOLWIND 2-5 (but certainly not SOLWIND 1). The
  tail was still quite bright on Sept. 25.08 and present but fainter on
  Sept. 25.14. Careful scrutiny of subsequent data reveals no trace of
  the comet reappearing from behind the occulted area. The line of sight
  was clearly very nearly in the comet's orbital plane. Computations
  by the undersigned suggest that the comet was very probably a member
  of the Kreutz group, a representative set of orbital elements being
  as follows: T = 1983 Sept. 25.19 ET, Peri. = 78.39, Node = 357.94,
  Incl. = 143.95 (equinox 1950.0), q = 0.0076 AU.

Title: Properties of Metre-Wavelength Solar Bursts Associated with
    Coronal Mass Ejections
Authors: Robinson, R. D.; Stewart, R. T.; Sheeley, N. R., Jr.; Howard,
   R. A.; Koomen, J.; Michels, D. J.
Bibcode: 1986SoPh..105..149R
Altcode:
  An investigation is made to determine the relationship between a
  coronal mass ejection (CME) and the characteristics of associated
  metre-wave activity. It is found that (1) the CME width and leading
  edge velocity can be highly influential in determining the intensity,
  spectral complexity and frequency coverage of both type II and continuum
  bursts; (2) the presence of a CME is possibly a necessary condition for
  the production of a metric continuum event and (3) metric continuum
  bursts as well as intense, complex type II events are preferentially
  associated with strong, long lasting soft X-ray events.

Title: The Origin of the 28-DAY to 29-DAY Recurrent Patterns of the
    Solar Magnetic Field
Authors: Sheeley, N. R., Jr.; DeVore, C. R.
Bibcode: 1986SoPh..104..425S
Altcode:
  Numerical simulations of the Sun's mean line-of-sight magnetic field
  suggest an origin for the 28-to 29-day recurrent patterns of the
  field and its associated interplanetary phenomena. The patterns are
  caused by longitudinal fluctuations in the eruption of new magnetic
  flux, the transport of this flux to mid latitudes by supergranular
  diffusion and meridional flow, and the slow rotation of the resulting
  flux distributions at the 28- to 29-day periods characteristic of
  those latitudes.

Title: SOLWIND observations of coronal mass ejections during 1979-1985
Authors: Sheeley, N. R., Jr.; Howard, R. A.; Koomen, M. J.; Michels,
   D. J.
Bibcode: 1986sfcp.nasa..241S
Altcode:
  Coronal observations have been processed for parts of each year during
  the interval 1979-1985. Around sunspot maximum, coronal mass ejections
  (CMEs) occurred at the rate of approximately 2 per day, and had a wide
  range of physical and morphological properties. During the recent years
  of relatively low sunspot number, CMEs occurred at the rate of only
  0.2 per day, and were dominated by the class of so-called streamer
  blowout. These special CMEs maintained a nearly constant occurrence
  rate of roughly 0.1 per day during the entire interval.

Title: Complimentary Aspects of the Mean and Gross Solar Magnetic
    Fields
Authors: DeVore, C. R.; Sheeley, N. R., Jr.
Bibcode: 1986BAAS...18..710D
Altcode:
  No abstract at ADS

Title: Solar Filament Eruptions and Energetic Particle Events
Authors: Kahler, S. W.; Cliver, E. W.; Cane, H. V.; McGuire, R. E.;
   Stone, R. G.; Sheeley, N. R., Jr.
Bibcode: 1986ApJ...302..504K
Altcode:
  The 1981 December 5 solar filament eruption that is associated with an
  energetic (E greater than 50 MeV) particle event observed at 1 AU. The
  eruption was photographed in H-alpha and was observed by the Solwind
  whitelight coronagraph on P78-1. It occurred well away from any solar
  active region and was not associated with an impulsive microwave burst,
  indicating that magnetic complexity and a detectable impulsive phase
  are not required for the production of a solar energetic particle (SEP)
  event. No metric type II or IV emission was observed, but an associated
  interplanetary type II burst was detected by the low-frequency radio
  experiment on ISEE 3. The December 5 and two other SEP events lacking
  evidence for low coronal shocks had unusually steep energy spectra
  (gamma greater than 3.5). In terms of shock acceleration, this suggests
  that shocks formed relatively high in the corona may produce steeper
  energy spectra than those formed at lower altitudes. It is noted that
  the filament itself maybe one source of the ions accelerated to high
  energies, since it is the only plausible coronal source of the He(+)
  ions observed in SEP events.

Title: The Decay of the Mean Solar Magnetic Field
Authors: Sheeley, N. R., Jr.; DeVore, C. R.
Bibcode: 1986SoPh..103..203S
Altcode:
  We have analyzed the effects that differential rotation and a
  hypothetical meridional flow would have on the evolution of the Sun's
  mean line-of-sight magnetic field as seen from Earth. By winding the
  large-scale field into strips of alternating positive and negative
  polarity, differential rotation causes the mean-field amplitude to decay
  and the mean-field rotation period to acquire the value corresponding to
  the latitude of the surviving unwound magnetic flux. For a latitudinally
  broad two-sector initial field such as a horizontal dipole, the decay
  is rapid for about 5 rotations and slow with a t<SUP>−1/2</SUP>
  dependence thereafter. If a poleward meridional flow is present,
  it will accelerate the decay by carrying the residual flux to high
  latitudes where the line-of-sight components are small. The resulting
  decay is exponential with an e-folding time of 0.75 yr (10 rotations)
  for an assumed 15 m s<SUP>−1</SUP> peak meridional flow speed.

Title: Coronal mass ejection associated with the stationary post-flare
    arch of 21 22 May 1980
Authors: McCabe, Marie K.; Švestka, Zdeněk F.; Howard, Russell A.;
   Jackson, Bernard V.; Sheeley, Neil R.
Bibcode: 1986SoPh..103..399M
Altcode:
  By using a combination of X-ray (HXIS), Hα (Haleakala), white-light
  corona (Solwind), and zodiacal light (Helios) images on 21-22 May, 1980
  we demonstrate, and try to explain, the co-existence of a coronal mass
  ejection with a stationary post-flare coronal arch. The mass ejection
  was seen, both by Solwind and Helios, in prolongation of the path of
  a powerful spray, whereas the active region filament did not erupt. A
  tentative comparison is made with other occurrences of stationary,
  or quasi-stationary post-flare coronal arches.

Title: Erratum - Numerical Simulations of Largescale Solar Magnetic
    Fields
Authors: DeVore, C. R.; Sheeley, N. R., Jr.; Boris, J. P.; Young,
   T. R., Jr.; Harvey, K. L.
Bibcode: 1986AuJPh..39..115D
Altcode:
  No abstract at ADS

Title: Solar gradual hard X-ray bursts: Observations and an
    interpretation
Authors: Cliver, E. W.; Dennis, B. R.; Kiplinger, A.; Kane, S.;
   Neidig, D. F.; Sheeley, N.; Koomen, M.
Bibcode: 1986AdSpR...6f.249C
Altcode: 1986AdSpR...6..249C
  A recent study of solar gradual hard X-ray bursts is summarized. The
  data are interpreted in terms of a model involving the acceleration
  and trapping of electrons in post flare loop systems following coronal
  mass ejections. A controversy about the classification of the metric
  continuum that typically accompanies gradual hard X-ray events is
  addressed.

Title: Coronal mass ejections and coronal structures.
Authors: Hildner, E.; Bassi, J.; Bougeret, J. L.; Duncan, R. A.;
   Gary, D. E.; Gergely, T. E.; Harrison, R. A.; Howard, R. A.; Illing,
   R. M. E.; Jackson, B. V.; Kahler, S. W.; Kopp, K.; Low, B. C.; Lantos,
   P.; Phillips, K. J. H.; Poletto, G.; Sheeley, N. R., Jr.; Stewart,
   R. T.; Svestka, Z.; Waggett, P. W.; Wu, S. T.
Bibcode: 1986NASCP2439....6H
Altcode:
  Contents: 1. Introduction. 2. Observations. 3. Initiation of
  coronal mass ejections - observations. 4. Modelling of coronal mass
  ejections and post-flare arches. 5. Interplanetary effects of coronal
  mass ejections. 6. The slowly varying corona near solar activity
  maximum. 7. Summary.

Title: The Solar Cycle Dependence of Coronal Mass Ejections
Authors: Howard, R. A.; Sheeley, N. R., Jr.; Michels, D. J.; Koomen,
   M. J.
Bibcode: 1986ASSL..123..107H
Altcode: 1986shtd.symp..107H
  The Solwind white light coronagraph on P78-1 has been making routine
  observations of the solar corona since March 28, 1979. Data from the
  1984/1985 time period has just been analyzed. During this interval,
  a period of low-solar-activity coronal mass ejections (CMEs) occurred
  at the rate of 0.2-0.4/day, in contrast to the rate of 1.8/day during
  the period around solar maximum, 1979-1981. The rate of equatorial
  CMEs also dropped by the same amount during this period. A class of
  CMEs, 'streamer blowouts', occurred at the same rate during the two
  epochs. Many of the parameters associated with CMEs, their type, their
  angular span, central latitude, mass, speed, and energy, have changed
  from their distributions at solar maximum. During the 1984/1985 period,
  CMEs are confined to low latitudes, rarely reaching the high latitudes
  seen during the maximum years. They are smaller, slower, less massive,
  and less energetic.

Title: Solwind observations of coronal mass ejections during 1979
    - 1985.
Authors: Sheeley, N. R., Jr.; Howard, R. A.; Koomen, M. J.; Michels,
   D. J.
Bibcode: 1986NASCP2421..241S
Altcode:
  Around sunspot maximum, coronal mass ejections (CMEs) occurred at the
  rate of approximately 2 per day, and had a wide range of physical and
  morphological properties. During the recent years of relatively low
  sunspot number, CMEs occurred at the rate of only 0.2 per day, and
  were dominated by the class of so-called "streamer blowouts." These
  special CMEs maintained a nearly constant occurrence rate of roughly
  0.1 per day during the entire interval.

Title: Simulations of Magnetic-Flux Transport in Solar Active Regions
Authors: DeVore, C. R.; Sheeley, N. R., Jr.; Boris, J. P.; Young,
   T. R., Jr.; Harvey, K. L.
Bibcode: 1985SoPh..102...41D
Altcode:
  We simulate the evolution of several observed solar active regions by
  solving a transport equation for magnetic flux at the photosphere. The
  rates of rotation, meridional flow, and diffusion of the flux are
  determined self-consistently in the calculations. Our findings
  are in good quantitative agreement with previous measures of the
  rotation rate and diffusion constant associated with photospheric
  magnetic fields. Although our meridional velocities are consistent
  in direction and magnitude with recently reported poleward flows,
  relatively large uncertainties in our velocity determinations make
  this result inconclusive.

Title: Probable Sungrazing Comets
Authors: Sheeley, N. R., Jr.; Howard, R.; Koomen, M.; Michels, D.;
   Marsden, B. G.
Bibcode: 1985IAUC.4129....1S
Altcode:
  N. R. Sheeley, Jr., Naval Research Laboratory, reports observations
  of two more probable sungrazing comets (cf. IAUC 3640, 3718, 3719)
  in the coronagraphic data from the P78-1 SOLWIND satellite. R. Howard,
  M. Koomen and D. Michels were also involved with these observations of
  what are tentatively called SOLWIND 4 and 5, and the Central Bureau
  in fact received the provisional data below some months before the
  deliberate destruction of the satellite on Sept. 13. Improved positions
  are anticipated for all five objects. The apparent heliocentric
  separation F (solar radii) and position angle O have been converted
  to R.A. and Decl. by the undersigned. SOLWIND 4 UT F O R.A. (1950.0)
  Decl. 1981 Nov. 3.999 10.5 205.0 14 29.5 -17 42 4.038 9.7 205.0 14
  30.0 -17 31 4.105 8.4 203.0 14 31.2 -17 15 4.171 7.2 200.6 14 32.3
  -17 01 4.238 5.8 197.1 14 33.5 -16 43 4.304 4.6 195.5 14 34.3 -16
  26 4.371 3.3? 188.5? 14 35.4 -16 08 SOLWIND 5 UT F O R.A. (1950.0)
  Decl. 1984 July 28.302 6.7 243.4 8 22.4 +18 15 28.309 6.6 243.8 8 22.5
  +18 16 28.316 6.4 244.2 8 22.7 +18 18 28.324 6.4 244.9 8 22.7 +18 19
  28.331 5.9 246.0 8 23.2 +18 24 28.368 4.8 247.6 8 24.4 +18 32 28.375
  4.6 248.3 8 24.6 +18 34 28.383 4.4 249.2 8 24.8 +18 36 28.390 4.2 250.2
  8 25.0 +18 38 28.397 3.9 250.8 8 25.3 +18 41 28.435 2.7 258.5 8 26.6
  +18 52 28.443 2.7 259.0 8 26.6 +18 52 Computations by the undersigned
  suggest that SOLWIND 5 is a member of the Kreutz group with T = 1984
  July 28.48 ET, Peri. = 62.28, Node = 337.30, Incl. = 139.14 (equinox
  1950.0), q = 0.0044 AU. Of all the comets SOLWIND 4 is least likely
  to belong to the Kreutz group, and the following very hypothetical
  elements have been derived: T = 1981 Nov. 4.6 ET, Peri. = 97.2, Node =
  25.6, Incl. = 113.7, q = 0.008 AU.

Title: Coronal mass ejections: 1979-1981
Authors: Howard, R. A.; Sheeley, N. R., Jr.; Michels, D. J.; Koomen,
   M. J.
Bibcode: 1985JGR....90.8173H
Altcode:
  In an examination of the Solwind coronagraph images obtained during
  the interval March 28, 1979, to December 31, 1981, we have identified
  998 coronal mass ejections and recorded their structural classes,
  central latitudes, latitudinal spans, speeds, excess brightnesses, and
  relative importances. A statistical analysis revealed the following
  general results. (1) The properties of coronal mass ejections (CMEs)
  depended strongly on their structure. Curved front, halo, and complex
  CMEs were the most energetic, and single spike, streamer blowout, and
  diffuse fan CMEs were the least energetic. CMEs occurred over a wide
  range of position angles, broadly centered on the equator, and had an
  average angular span of 45°. The leading edge moved at an average
  of approximately 470 km/s, and the average ejected mass and kinetic
  energy were 4.1×10<SUP>15</SUP> g and 3.5×10<SUP>30</SUP> erg,
  respectively. The average CME proton flux at the equator at 1 AU was
  2.2×10<SUP>7</SUP> cm<SUP>-2</SUP> s<SUP>-1</SUP> or approximately 5%
  of the measured in situ flux during 1971-1976. (2) During 1979-1981,
  the average occurrence rate was 1.8/day for all CMEs, 0.9/day for
  ``major'' CMEs, and 0.15/day for all CMEs that crossed the equator and
  had an angular span of at least 45°. (3) The temporal variations in
  the CME occurrence rate did not show an obvious persistent relation to
  the variations in the sunspot number on time scales ranging from 7 to
  180 days. During 1979-1981 the maximum in the 180-day average CME rate
  peaked in the second half of 1980, whereas the 180-day average sunspot
  number peaked during the firt half of 1980. <P />The 180-day average
  rate of fast CMEs (speeds of at least 800 km/s) had a monotonic increase
  that seemed to be more closely associated with the occurrence rate of
  large solar flares than with the variation of the sunspot number.

Title: Simulations of the Mean Solar Magnetic Field during Sunspot
    CYCLE-21
Authors: Sheeley, N. R., Jr.; DeVore, C. R.; Boris, J. P.
Bibcode: 1985SoPh...98..219S
Altcode:
  Regarding new bipolar magnetic regions as sources of flux, we have
  computed the evolution of the photospheric magnetic field during
  1976-1984 and derived the corresponding evolution of the mean
  line-of-sight field as seen from Earth. We obtained a good, but
  imperfect, agreement between the observed mean field and the field
  computed for a nominal choice of flux transport parameters. Also,
  we determined the response of the computed mean field to variations
  in the transport parameters and the source properties. The results
  lead us to regard the mean-field evolution as a random-walk process
  with dissipation. New eruptions of flux produce the random walk,
  and together differential rotation, meridional flow (if present), and
  diffusion provide the dissipation. The net effect of each new source
  depends on its strength and orientation (relative to the strength and
  orientation of the mean field) and on the time elapsed before the next
  eruption (relative to the decay time of the field). Thus the mean field
  evolves principally due to the contributions of the larger sources,
  which produce a strong, gradually evolving field near sunspot maximum
  but a weak, sporadically evolving field near sunspot minimum.

Title: White Light and Radio Sounding Observations of Coronal
    Transients
Authors: Bird, M. K.; Volland, H.; Howard, R. A.; Koomen, M. J.;
   Michels, D. J.; Sheeley, N. R., Jr.; Amstrong, J. W.; Seidel, B. L.;
   Stelzried, C. T.; Woo, R.
Bibcode: 1985SoPh...98..341B
Altcode:
  A concerted search for coronal transients was conducted with the
  `Solwind' coronagraph during the solar occultations of the two
  Helios spacecraft in October/November 1979. The polarization angle
  and bandwidth of the linearly polarized S-band downlink signal were
  monitored at the three 64-m tracking stations of the NASA Deep
  Space Network to determine coronal Faraday rotation and spectral
  broadening. A one-to-one correspondence could be established between
  abrupt disturbances in the two signal parameters and the passage of
  a white-light transient through the signal ray path from spacecraft
  to Earth. The white-light morphology and the additional information
  provided by the radio sounding coverage are presented for each of the
  five distinct events recorded. Although no specific example could
  be observed in sufficient detail in both white light and Faraday
  rotation to derive the small-scale magnetic structure, some qualitative
  descriptions of the orientation and rough estimates of the magnitude
  of the transient magnetic field could be made.

Title: Energetic Protons from a Disappearing Solar Filament
Authors: Kahler, S. W.; Cliver, E. W.; Cane, H. V.; McGuire, R. E.;
   Stone, R. G.; Sheeley, N. R., Jr.
Bibcode: 1985ICRC....4...94K
Altcode: 1985ICRC...19d..94K
  A solar energetic (E 50 MeV) particle (SEP) event observed at 1 AU began
  about 15000 UT on 1981 December 5. This event was associated with a fast
  coronal mass ejection observed with the Solwind coronagraph on the P78-1
  satellite. No metric type 2 or type 4 burst was observed, but a weak
  interplanetary type 2 burst was observed with the low frequency radio
  experiment on the International Sun-Earth Explorer-3 satellite. The mass
  ejection was associated with the eruption of a large solar quiescent
  filament which lay well away from any active regions. The eruption
  resulted in an H alpha double ribbon structure which straddled the
  magnetic inversion line. No impulsive phase was obvious in either
  the H alpha or the microwave observations. This event indicates that
  neither a detectable impulsive phase nor a strong or complex magnetic
  field is necessary for the production of energetic ions.

Title: Helios spacecraft and earth perspective observations of three
    looplike solar mass ejection transients
Authors: Jackson, B. V.; Howard, R. A.; Sheeley, N. R., Jr.; Michels,
   D. J.; Koomen, M. J.; Illing, R. M. E.
Bibcode: 1985JGR....90.5075J
Altcode:
  Three looplike mass ejection transients observed from earth with the
  SOLWIND coronagraph and the solar maximum mission coronagraph are
  imaged by Helios spacecraft zodiacal light photometers. Because the
  Helios spacecraft are not earth orbiting, views of these ejections
  from the two perspectives allow conclusions to be drawn about their
  three-dimensional shapes. The mass ejection of May 24, 1979, in
  Helios data is concentrated in an outer structure followed by bright
  features separated by a region of depleted material. The ejections of
  June 18 and 29, 1980, appear restricted in position angle in Helios
  observations to less and the same, respectively, as in coronagraph
  observations. The observations imply that the ejections essentially
  retain their basic structure and speed out to heights (0.2-0.4 AU)
  observed by the Helios spacecraft.

Title: The Frequency of Long-Duration Solar X-Ray Events
Authors: Koomen, M. J.; Sheeley, N. R., Jr.; Howard, R. A.; Michels,
   D. J.
Bibcode: 1985SoPh...97..375K
Altcode:
  It is shown that the long-duration X-ray events tend to ignore the
  sunspot cycle. This is particularly true for events with durations of
  6 hr or more.

Title: High-resolution X-ray spectra of solar flares. VII - A
    long-duration X-ray flare associated with a coronal mass ejection
Authors: Kreplin, R. W.; Doschek, G. A.; Feldman, U.; Sheeley, N. R.,
   Jr.; Seely, J. F.
Bibcode: 1985ApJ...292..309K
Altcode:
  It has been recognized that very long duration X-ray events
  (lasting several hours) are frequently associated with coronal mass
  ejection. Thus, Sheeley et al. (1983) found that the probability of the
  occurrence of a coronal mass ejection (CME) increases monotonically
  with the X-ray event duration time. It is pointed out that the
  association of long-duration, or long-decay, X-ray events (LDEs) with
  CMEs was first recognized from analysis of solar images obtained by
  the X-ray telescopes on Skylab and the Naval Research Laboratory (NRL)
  slitless spectroheliograph. Recently high-resolution Bragg crystal
  X-ray spectrometers have been flown on three spacecraft, including the
  Department of Defense P78-1 spacecraft, the NASA Solar Maximum Mission
  (SMM), and the Japanese Hinotori spacecraft. In the present paper,
  P78-1 X-ray spectra of an LDE which had its origin behind the solar
  west limb on November 14, 1980 is presented. The obtained data make
  it possible to estimate temperatures of the hottest portion of the
  magnetic loops in which the emission arises.

Title: A comparison of solar helium-3-rich events with type II bursts
    and coronal mass ejections
Authors: Kahler, S.; Reames, D. V.; Sheeley, N. R., Jr.; Howard,
   R. A.; Michels, D. J.; Koomen, M. J.
Bibcode: 1985ApJ...290..742K
Altcode:
  The authors ask whether the energetic particles of <SUP>3</SUP>He-rich
  events are accelerated in the same process as that resulting in
  particles of normal-abundance events. They first present a list
  of 66 <SUP>3</SUP>He-rich events observed with the Goddard Space
  Flight Center particle detector on ISEE 3. It is then shown that
  these events are not statistically associated with either of the two
  common signatures of normal-abundance events, metric type II bursts
  and coronal mass ejections. This indicates that enhanced abundance
  events may be produced only in the impulsive phases of flares, while
  normal abundance events are produced in subsequent flare shock waves.

Title: The Mass Distribution of Coronal Mass Ejections
Authors: Jackson, B. V.; Howard, R. A.; Koomen, M. J.; Michels, D. J.;
   Sheeley, N. R., Jr.
Bibcode: 1985BAAS...17..636J
Altcode:
  No abstract at ADS

Title: A Stochastic Model for the Mean Solar Magnetic Field During
    the Sunspot Cycle
Authors: DeVore, C. R.; Sheeley, N. R., Jr.
Bibcode: 1985BAAS...17..642D
Altcode:
  No abstract at ADS

Title: Numerical Simulations of the Mean Solar Magnetic Field During
    the Sunspot Cycle
Authors: Sheeley, N. R., Jr.; DeVore, C. R.
Bibcode: 1985BAAS...17R.642S
Altcode:
  No abstract at ADS

Title: Doppler scintillation observations of interplanetary shocks
    within 0.3 AU
Authors: Woo, Richard; Armstrong, J. W.; Sheeley, N. R.; Howard,
   R. A.; Koomen, M. J.; Michels, D. J.; Schwenn, R.
Bibcode: 1985JGR....90..154W
Altcode:
  Near-sun spacecraft Doppler scintillation observations have been
  combined with Solwind coronagraph and Helios 1 plasma measurements to
  provide more definitive measurements of the evolution and propagation
  of interplanetary shock waves between the sun and earth orbit than
  have been available from previous observations. This study shows that
  substantial deceleration of fast shocks (shock speeds exceeding 1000 km
  s<SUP>-</SUP><SUP>1</SUP>) takes place near the sun and that the amount
  of deceleration increases with shock speed. This is consistent with
  the significantly lower and rather narrow range of shock velocities
  observed by direct spacecraft near earth orbit. When coronal mass
  ejection (CME) speeds are available for the fast shocks, they are
  considerably lower than the speeds measured farther out but near the
  sun. This implies that either the fast shocks first accelerate before
  decelerating on their way out from the sun (assuming the CME front
  is identified with the shock) or the CME speeds do not represent and
  substantially underestimate the shock speeds in the outer corona. If
  the CME speeds underestimate the shock speeds of the fast shocks, they
  do not appear to do so for the slow shocks. If the shocks are being
  driven over distances indicated by the acceleration region or to the
  point where deceleration begins, then their velocity profiles imply
  that the slower shocks are being driven farther out than the faster
  shocks. The analysis of one piston-driven shock shows the velocity of
  the contact surface is about 0.58 that of the shock front velocity.

Title: Numerical simulations of large-scale solar magnetic fields
Authors: DeVore, C. R.; Boris, J. P.; Young, T. R., Jr.; Sheeley,
   N. R.; Harvey, K. L.
Bibcode: 1985AuJPh..38..999D
Altcode:
  The authors have solved numerically a transport equation which describes
  the evolution of the large-scale magnetic field of the Sun. Data
  derived from solar magnetic observations are used to initialize the
  computations and to account for the emergence of new magnetic flux
  during the sunspot cycle. The authors' objective is to assess the
  ability of the model to reproduce the observed evolution of the field
  patterns. They discuss recent results from simulations of individual
  active regions over a few solar rotations and of the magnetic field
  of the Sun over sunspot cycle 21.

Title: Coronal mass ejections and interplanetary shocks
Authors: Sheeley, N. R., Jr.; Howard, R. A.; Michels, D. J.; Koomen,
   M. J.; Schwenn, R.; Muehlhaeuser, K. H.; Rosenbauer, H.
Bibcode: 1985JGR....90..163S
Altcode:
  A comparison between Solwind observations of coronal mass ejections
  (CME's) and Helios 1 observations of interplanetary shocks during
  1979-1982 indicates that 72% of the shocks were associated with large,
  low-latitude mass ejections on the nearby limb. Most of the associated
  CME's has speeds in excess of 500 km/s, but some of them had speeds in
  the range 200-400 km/s. An additional 26% of the shocks may have been
  associated with CME's, but we were less confident of these associations
  because the sizes and locations of the CME's did not seem appreciably
  different from those of the numerous CME's without Helios shocks. Only
  2% of the shocks clearly lacked CME's. As the average level of sunspot
  activity declined during 1982, the shock frequency also declined, but
  the observed shocks and some of their associated CME's had unusually
  high speeds well in excess of 1000 km/s.

Title: Characteristics of coronal mass ejections associated with
    solar frontside and backside metric type II bursts
Authors: Kahler, S. W.; Cliver, E. W.; Sheeley, N. R.; Howard, R. A.;
   Koomen, M. J.; Michels, D. J.
Bibcode: 1985JGR....90..177K
Altcode:
  We compare fast (v&gt;=500 km s<SUP>-</SUP><SUP>1</SUP>) coronal
  mass ejections (CME's) with reported metric type II bursts to study
  the properties of CME's associated with coronal shocks. We confirm
  an earlier report of fast frontside CME's with no associated metric
  type II bursts and calculate that 33+/-15% of all fast frontside CME's
  are not associated with such bursts. Faster CME's are more likely to
  be associated with type II bursts, as expected from the hypothesis
  of piston-driven shocks. However, CME brightness and associated
  peak 3-cm burst intensity are also important factors, as might be
  inferred from the Wagner and MacQueen (1983) view of type II shocks
  decoupled from associated CME's. We use the equal visibility of solar
  frontside and backside CME's to deduce the observability of backside
  type II bursts. We calculate that 23+/-7% of all backside type II bursts
  associated with fast CME's can be observed at the earth and that 13+/-4%
  of all type II bursts originate in backside flares. CME speed again
  is the most important factor in the observability of backside type
  II bursts.

Title: Associations beteen coronal mass ejections and solar energetic
    proton events
Authors: Kahler, S. W.; Sheeley, N. R., Jr.; Howard, R. A.; Michels,
   D. J.; Koomen, M. J.; McGuire, R. E.; von Rosenvinge, T. T.; Reames,
   D. V.
Bibcode: 1984JGR....89.9683K
Altcode:
  We have used data from the Naval Research Laboratory (NRL) white
  light coronograph on the P78-1 spacecraft and energetic (E&gt;4 MeV)
  proton data from the Goddard Space Flight Center (GSFC) detectors
  on the IMP 8 and ISEE 3 spacecraft to investigate the association
  between proton events originating in flares and coronal mass ejections
  (CME's). The primary data were 50 prompt proton events observed between
  April 1979 and February 1982 for which reduced coronograph data were
  available. H alpha flares could be confidently associated with 27 of
  these events, and in 26 of these 27 cases an associated CME was found,
  indicating a high but not perfect association of prompt proton events
  with CME's. Peak proton fluxes correlate with both the speeds and the
  angular sizes of the associated CME's. We show that the CME speeds do
  not significantly correlate with CME angular sizes, so that the peak
  proton fluxes are correlated with two independent CME parameters. With
  larger angular sizes, CME's are more likely to be loops and fans
  rather than jets and spikes and are more likely to intersect the
  ecliptic. Which of these factors is important to the peak proton flux
  correlation cannot be determined from the data. We find weak evidence
  that steeper proton spectra are associated with faster and wider
  CME's. Two of the 50 proton events of the study and two additional
  events, all with no associated CME's share common characteristics:
  relatively short duration (~1) day proton events with low fluxes,
  parent flares with short (~10 min) soft x ray duration, close magnetic
  connection to the earth, and gamma ray and metric type II emission.

Title: Coronal Mass Ejections and Sudden Filament Disappearances
Authors: Sheeley, N. R., Jr.; Howard, R. A.; Harvey, K. L.
Bibcode: 1984BAAS...16..930S
Altcode:
  No abstract at ADS

Title: Characteristics of Flares Producing Metric Type-II Bursts
    and Coronal Mass Ejections
Authors: Kahler, S.; Sheeley, N. R., Jr.; Howard, R. A.; Koomen,
   M. J.; Michels, D. J.
Bibcode: 1984SoPh...93..133K
Altcode:
  We attempt to study the origin of coronal shocks by comparing several
  flare characteristics for two groups of flares: those with associated
  metric type II bursts and coronal mass ejections (CMEs) and those
  with associated metric type II bursts but no CMEs. CMEs accompany
  about 60% of all flares with type II bursts for solar longitudes
  greater than 30°, where CMEs are well observed with the NRL Solwind
  coronagraph. Hα flare areas, 1-8 Å X-ray fluxes, and impulsive 3 cm
  fluxes are all statistically smaller for events with no CMEs than for
  events with CMEs. It appears that both compact and large mass ejection
  flares are associated with type II bursts. The events with no CMEs
  imply that at least many type II shocks are not piston-driven, but
  the large number of events of both groups with small 3 cm bursts does
  not support the usual assumption that type II shocks are produced by
  large energy releases in flare impulsive phases. The poor correlation
  between 3 cm burst fluxes and the occurrence of type II bursts may be
  due to large variations in the coronal Alfvén velocity.

Title: The concentration of the large-scale solar magnetic field by
    a meridional surface flow
Authors: DeVore, C. R.; Boris, J. P.; Sheeley, N. R., Jr.
Bibcode: 1984SoPh...92....1D
Altcode:
  We calculate analytical and numerical solutions to the magnetic flux
  transport equation in the absence of new bipolar sources of flux, for
  several meridional flow profiles and a range of peak flow speeds. We
  find that a poleward flow with a broad profile and a nominal 10 m
  s<SUP>−1</SUP> maximum speed concentrates the large-scale field
  into very small caps of less than 15° half-angle, with average field
  strengths of several tens of gauss, contrary to observations. A flow
  which reaches its peak speed at a relatively low latitude and then
  decreases rapidly to zero at higher latitudes leads to a large-scale
  field pattern which is consistent with observations. For such a flow,
  only lower latitude sunspot groups can contribute to interhemispheric
  flux annihilation and the resulting decay and reversal of the polar
  magnetic fields.

Title: Associations between coronal mass ejections and metric type
    II bursts
Authors: Sheeley, N. R., Jr.; Howard, R. A.; Michels, D. J.; Robinson,
   R. D.; Koomen, M. J.; Stewart, R. T.
Bibcode: 1984ApJ...279..839S
Altcode:
  A statistical comparison of metric type II bursts and coronal
  mass ejections (CMEs) during 1979-1982 was carried out. Type II
  bursts without CMEs were associated with short-lived (0.5 hr) soft
  X-ray events, but not with interplanetary shocks at the Helios 1
  spacecraft. Type II bursts with CMEs were associated with longer-lived
  X-ray events (3 hr on the average) and interplanetary shocks, and
  the CMEs had speeds greater than 400 km/s. CMEs without metric type
  II bursts were divided equally into groups faster and slower than 455
  km/s. The faster CMEs were associated with interplanetary shocks, some
  of which originated on the visible disk where metric type II bursts
  should have been observed if they had occurred. These results suggest
  that (1) shocks without CMEs have a relatively impulsive origin and may
  die out sooner than many shocks with CMEs which are piston driven, and
  (2) either some fast CMEs do not reach shock-producing super-Alfvenic
  speeds until they leave the lower corona where the metric emission
  originates, or these CMEs form shocks that are unable to excite type
  II emission in the lower corona.

Title: The Propagation of Transient Solar Events
Authors: Sheeley, N. R., Jr.; Howard, R. A.; Michels, D. J.; Koomen,
   M. J.
Bibcode: 1984BAAS...16Q.454S
Altcode:
  No abstract at ADS

Title: The Temporal Variation of Coronal Mass Ejections During
    1979-1981
Authors: Howard, R. A.; Sheeley, N. R., Jr.; Michels, D. J.; Koomen,
   M. J.
Bibcode: 1984BAAS...16..454H
Altcode:
  No abstract at ADS

Title: Solar Energetic Proton Events Unassociated with Coronal
    Mass Ejections
Authors: Kahler, S.; Evenson, P.; McGuire, R. E.; Reames, D. V.;
   von Rosenvinge, T. T.; Sheeley, N. R., Jr.; Howard, R. A.; Koomen,
   M. J.; Michels, D. J.
Bibcode: 1984BAAS...16..453K
Altcode:
  No abstract at ADS

Title: Synoptic observations of coronal transients and their
    interplanetary consequences
Authors: Michels, D. J.; Sheeley, N. R., Jr.; Howard, R. A.; Koomen,
   M. J.; Schwenn, R.; Mulhauser, K. H.; Rosenbauer, H.
Bibcode: 1984AdSpR...4g.311M
Altcode: 1984AdSpR...4..311M
  A small coronagraph has been placed in orbit to monitor the sun's
  outer corona from 2.5 to 10.0 solar radii, and five years of nearly
  continuous synoptic observations have now been completed. Rapid and
  sensitive image processing techniques have been developed to screen
  the data for transient phenomena, particularly coronal mass ejections
  (CMEs). About 50,000 coronal images have been examined, out of a
  five-year total of 68,000, and a standardized listing of more than 1,200
  coronal transients for the period 1979-1982 has been prepared. These
  data have been analysed in the light of other available information,
  particularly on conditions in the interplanetary plasma. The dynamical
  characteristics of the active corona, as they are beginning to emerge
  from the data, are presented. We find that coronal mass ejections
  exercise significant influence on the interplanetary solar wind. They
  are the source of disturbances that are frequent and energetic,
  that tend to be somewhat focussed, that often reach shock intensity,
  and that propagate to large heliocentric distances, sometimes causing
  major geomagnetic storms.

Title: Evolution of solar magnetic flux.
Authors: Boris, J. P.; DeVore, C. R.; Golub, L.; Howard, R. F.; Low,
   B. C.; Sheeley, N. R., Jr.; Simon, G. W.; Tsinganos, K. C.
Bibcode: 1984NASRP1120....3B
Altcode:
  Contents: Introduction. Appearance of magnetic flux: models for flux
  emergence, unexplained observations. Dynamics of surface magnetic
  flux: magnetic flux transport, magnetic flux structure. Disappearance
  of magnetic flux: theoretical considerations, observations of flux
  disappearance. Summary.

Title: Coronal transients and their interplanetary effects.
Authors: Hundhausen, A. J.; Burlaga, L. F.; Feldman, W. C.; Gosling,
   J. T.; Hildner, E.; House, L. L.; Howard, R. A.; Krieger, A. S.;
   Kundu, M. R.; Low, B. C.; Sheeley, N. R., Jr.; Steinolfson, R. S.;
   Stewart, R. T.; Stone, R. G.; Wu, S. T.
Bibcode: 1984NASRP1120....6H
Altcode:
  Contents: 1. Introduction. 2. Background material: Ancient history -
  solar flares and geomagnetic storms. Modern history - interplanetary
  shock waves. Coronal transients or mass ejections. 3. The present:
  Theoretical models. New observations of coronal mass ejections. 4. The
  future: Solar origins. Interplanetary effects.

Title: Evidence for Directivity of Coronal Transients
Authors: Michels, D. J.; Howard, R. A.; Sheeley, N. R., Jr.; Koomen,
   M. J.
Bibcode: 1984sii..conf..319M
Altcode:
  No abstract at ADS

Title: Long-term synoptic observations of Solar coronal mass ejections
Authors: Michels, D. J.; Howard, R. A.; Koomen, M. J.; Sheeley, N. R.
Bibcode: 1984stp..conf..367M
Altcode:
  No abstract at ADS

Title: The Gle-Associated Flare of 21 August 1979
Authors: Cliver, E. W.; Kahler, S. W.; Cane, H. V.; Koomen, M. J.;
   Michels, D. J.; Howard, R. A.; Sheeley, N. R., Jr.
Bibcode: 1984sii..conf..205C
Altcode:
  No abstract at ADS

Title: The statistical properties of coronal mass ejections during
    1979-1981
Authors: Howard, R. A.; Sheeley, N. R.; Koomen, M. J.; Michels, D. J.
Bibcode: 1984AdSpR...4g.307H
Altcode: 1984AdSpR...4..307H
  The Solwind coronagraph on the P78-1 earth-orbiting satellite has been
  monitoring the Sun routinely at 10-minute intervals during the 5-year
  interval from April, 1979 to the present. In a statistical analysis of
  about 1000 mass ejections observed through the end of 1981, we find an
  average occurrence rate of 1.8 mass ejections per day. Histograms of
  speed, central latitude, angular span, brightness, and other parameters
  have been constructed, and properties such as shape classification have
  been tabulated. These characteristics are summarized for these years
  near sunspot maximum. The average speed and mass estimate are found to
  be similar to those found at the declining phase of the previous sunspot
  cycle. The angular span and central latitude distributions are quite
  different than seen during the declining phase, and are very dependent
  upon structural class. The fluctuations in the occurrence rate of CMEs
  does not seem to match the fluctuations in the sunspot number. There
  is a tendency for high speed CMEs to occur more frequently in 1981
  than in 1980, and more frequently in 1980 than in 1979.

Title: Radio and Visible Light Observations of a Coronal Arcade
    Transient
Authors: Gergely, T. E.; Kundu, M. R.; Erksine, F. T., III; Sawyer, C.;
   Wagner, W. J.; Illing, R.; House, L. L.; McCabe, M. K.; Stewart, R. T.;
   Nelson, G. J.; Koomen, M. J.; Michels, D.; Howard, R.; Sheeley, N.
Bibcode: 1984SoPh...90..161G
Altcode:
  We discuss simultaneous visible-light and radio observations of
  a coronal transient that occurred on 9 April, 1980. Visible-light
  observations of the transient and the associated erupting prominence
  were available from the Coronagraph/Polarimeter carried aboard SMM,
  the P78-1 coronagraph, and from the Haleakala Observatory. Radio
  observations of the related type III-II-IV bursts were available from
  the Clark Lake and Culgoora Observatories. The transient was extremely
  complex; we suggest that an entire coronal arcade rather than just a
  single loop participated in the event. Type III burst sources observed
  at the beginning of the event were located along a nearby streamer,
  which was not disrupted, but was displaced by the outmoving loops. The
  type II burst showed large tangential motion, but unlike such sources
  usually do, it had no related herringbone structure. A moving type
  IV burst source can be associated with the most dense feature of the
  white-light transient.

Title: Coronal Transients Observed during Solar Occultation of the
    HELIOS Spacecraft in STIP Interval VIII
Authors: Bird, M. K.; Volland, H.; Howard, R. A.; Koomen, M. J.;
   Michels, D. J.; Sheeley, N. R., Jr.; Armstrong, J. W.; Seidel, B. L.;
   Stelzried, C. T.; Woo, R.
Bibcode: 1984sii..conf..101B
Altcode:
  No abstract at ADS

Title: The GLE-associated flare of 21 August, 1979
Authors: Cliver, E. W.; Kahler, S. W.; Cane, H. V.; Koomen, M. J.;
   Michels, D. J.; Howard, R. A.; Sheeley, N. R., Jr.
Bibcode: 1983SoPh...89..181C
Altcode:
  We use a variety of ground-based and satellite measurements to identify
  the source of the ground level event (GLE) beginning near 06∶30 UT on
  21 August, 1979 as the 2B flare with maximum at ∼06∶15 UT in McMath
  region 16218. This flare differed from previous GLE-associated flares
  in that it lacked a prominent impulsive phase, having a peak ∼9 GHz
  burst flux density of only 27 sfu and a ≳20 keV peak hard X-ray flux
  of ≲3 × 10<SUP>-6</SUP> ergs cm<SUP>-2</SUP>s<SUP>-1</SUP>. Also,
  McMath 16218 was magnetically less complex than the active regions in
  which previous cosmic-ray flares have occurred, containing essentially
  only a single sunspot with a rudimentary penumbra. The flare was
  associated with a high speed (≳700 km s<SUP>-1</SUP>) mass ejection
  observed by the NRL white light coronagraph aboard P78-1 and a shock
  accelerated (SA) event observed by the low frequency radio astronomy
  experiment on ISEE-3.

Title: Associations between coronal mass ejections and interplanetary
    shocks.
Authors: Sheeley, N. R., Jr.; Howard, R. A.; Koomen, M. J.; Michels,
   D. J.; Schwenn, R.; Muhlhauser, K. H.; Rosenbauer, H.
Bibcode: 1983NASCP.2280.693S
Altcode: 1983sowi.conf..693S
  The authors are in the process of comparing nearly continuous
  complementary coronal observations and interplanetary plasma
  measurements for the years 1979 - 1982. Their preliminary results
  show that almost all low-latitude high-speed coronal mass ejections
  (CME's) were associated with shocks at HELIOS 1. Some suitably directed
  low-speed CME's were clearly associated with shocks while others may
  have been associated with disturbed plasma (such as NCDE's) without
  shocks. A few opposite-hemisphere CME's associated with great flares
  also seemed to have been associated with shocks at HELIOS.

Title: Associations between coronal mass ejections and soft X-ray
    events
Authors: Sheeley, N. R., Jr.; Howard, R. A.; Koomen, M. J.; Michels,
   D. J.
Bibcode: 1983ApJ...272..349S
Altcode:
  The association between white light coronal mass ejections (CMEs)
  and full-disk X ray events have been examined as a function of
  X ray duration during the recent years of high sunspot activity
  (1979-1981). On a time scale of hours, no duration interval has been
  found that separates X ray events into two distinct classes depending
  on whether or not they have associated CMEs. Rather, the tendency for
  long-duration X ray events to have associated CMEs reflects the fact
  that, as X ray duration increases, the differential distribution of
  events without CMEs falls off faster than the distriution of X ray
  events with CMEs.

Title: The Correlation of Coronal Mass Ejections with Energetic
    Flare Proton Events
Authors: Kahler, S. W.; McGuire, R. E.; Reames, D. V.; von Rosenvinge,
   T. T.; Sheeley, N. R., Jr.; Howard, R. A.; Michels, D. J.; Koomen,
   M. J.
Bibcode: 1983ICRC....4....6K
Altcode: 1983ICRC...18d...6K
  Proton events of energies of at least 4 MeV presumed due to solar
  flares are compared with coronal mass ejections (CMEs) observed with
  an orbiting coronagraph. H alpha flares are associated with 27 of
  the 50 flare proton events of the study. Each of these 27 flares
  is then associated temporally and spatially with a CME, confirming
  the earlier conclusion, based on Skylab data, that a CME may be a
  necessary condition for a flare proton event. Peak 4-22 MeV proton
  fluxes correlate with both the speeds and the angular sizes of the
  associated CMEs. CMEs of larger angular sizes are more likely to
  be loops or fans rather than jets or spikes and are more likely to
  intersect the ecliptic.

Title: Helios Images of a Coronal Mass Ejection Transient
Authors: Jackson, B. V.; Howard, R. A.; Koomen, M. J.; Michels, D. J.;
   Sheeley, N. R.
Bibcode: 1983BAAS...15..705J
Altcode:
  No abstract at ADS

Title: Major Mass Ejection Rate From Three Space Coronagraphs
Authors: Sawyer, C.; Howard, R.; Sheeley, N.; Koomen, M.; Michels, D.
Bibcode: 1983BAAS...15..706S
Altcode: 1983BAAS...15..683M
  No abstract at ADS

Title: On the Nature of Coronal Mass Ejections During the Period 28
    March 1979 through 30 June 1981
Authors: Howard, R. A.; Sheeley, N. R., Jr.; Koomen, M. J.; Michels,
   D. J.
Bibcode: 1983BAAS...15R.703H
Altcode:
  No abstract at ADS

Title: The solar corona on 31 July, 1981
Authors: Fisher, R. R.; Lacey, L. R.; Rock, K. A.; Yasukawa, E. A.;
   Sheeley, N. R., Jr.; Michels, D. J.; Howard, R. A.; Koomen, M. J.;
   Bagrov, A.
Bibcode: 1983SoPh...83..233F
Altcode:
  Various instruments were used to observe the solar corona near or at
  the time of total eclipse, 31 July, 1981. The High Altitude Observatory
  (HAO) coronal eclipse camera and the MK-III K-coronameter recorded the
  lower portions of the corona; the distribution of white light material
  above 3 R<SUB>⊙</SUB> was observed with the Naval Research Laboratory
  (NRL) satellite coronagraph on P78-1. These data sets are used to
  describe coronal structure and to identify coronal active regions. The
  polar coronal holes, as developed at this time in the solar cycle, were
  offset from the poles of rotation; both were seen displaced eastward
  on eclipse day. High latitude streamers appear in all three data sets,
  extending from the base of the corona outward to at least eight solar
  radii from Sun center. At least two transients were observed by the NRL
  experiment on the eclipse day, but it is likely that no transient was in
  progress during any observation along the eclipse path. A distribution
  of the white-light corona, derived from synoptic K-coronameter data,
  is given.

Title: Meridional Flows and Magnetic Flux Transport on the Sun
Authors: Boris, J. P.; Sheeley, N. R., Jr.; Young, T. R., Jr.; DeVore,
   C. R.; Harvey, K. L.
Bibcode: 1983BAAS...15R.701B
Altcode:
  No abstract at ADS

Title: Coronal Mass Ejections and Interplanetary Disturbances
Authors: Sheeley, N. R., Jr.; Howard, R. A.; Koomen, M. J.; Michels,
   D. J.; Schween, R.; Muhlauser, K. H.; Rosenbauer, H.
Bibcode: 1983BAAS...15..699S
Altcode:
  No abstract at ADS

Title: Observations of Major Flares in He I 10830
Authors: Harvey, K. L.; Recely, F.; Sheeley, N. R., Jr.; Howard,
   R. A.; Koomen, M. J.; Michels, D. J.
Bibcode: 1983BAAS...15..712H
Altcode:
  No abstract at ADS

Title: Associations between Coronal Mass Ejections and Solar Energetic
    Proton Events
Authors: Kahler, S. W.; Sheeley, N. R., Jr.; Howard, R. A.; Koomen,
   M. J.; Michels, D. J.; McGuire, R. E.; von Rosenvinge, T. T.; Reames,
   D. V.
Bibcode: 1983BAAS...15..699K
Altcode:
  No abstract at ADS

Title: A White-Light / Fex / Hα Coronal Transient Observation to
    10-SOLAR-RADII
Authors: Wagner, W. J.; Illing, R. M. E.; Sawyer, C. B.; House, L. L.;
   Sheeley, N. R., Jr.; Howard, R. A.; Koomen, M. J.; Michels, D. J.;
   Smartt, R. N.; Dryer, M.
Bibcode: 1983SoPh...83..153W
Altcode:
  Multi-telescope observations of the coronal transient of 15-16
  April, 1980 provide simultaneous data from the Solar Maximum Mission
  Coronagraph/Polarimeter, the Solwind Coronagraph, and the new Emission
  Line Coronagraph of the Sacramento Peak Observatory. An eruptive
  prominence-associated white light transient is for the first time
  seen as an unusual wave or brightening in Fe Xgl6374 (but not in
  Fe XIVgl5303). Several interpretations of this fleeting enhancement
  are offered.

Title: A quantitative study of magnetic flux transport on the Sun
Authors: Sheeley, N. R., Jr.; Boris, J. P.; Young, T. R., Jr.; DeVore,
   C. R.; Harvey, K. L.
Bibcode: 1983IAUS..102....2S
Altcode:
  A computational model, based on diffusion, differential rotation,
  and meridional flow, has been developed to simulate the transport
  of magnetic flux on the Sun. Using Kitt Peak magnetograms as input,
  as have determined a best-fit diffusion constant by comparing the
  computed and observed fields at later times. This paper presents
  the initial results of a project to simulate the transport of solar
  magnetic flux using diffusion, differential rotation, and meridional
  flow. The study concerns the evolution of large-scale fields on a time
  scale of weeks of years, and ignores the rapid changes that accompany
  the emergence of new magnetic regions and the day-to-day changes of
  the supergranular network itself.

Title: A Quantitative Study of Magnetic Flux Transport on the Sun
Authors: Sheeley, N. R., Jr.; Boris, J. P.; Young, T. R., Jr.; DeVore,
   C. R.; Harvey, K. L.
Bibcode: 1983IAUS..102..273S
Altcode:
  A computational model, based on diffusion, differential rotation, and
  meridional circulation, has been developed to simulate the transport
  of magnetic flux on the Sun. Using Kitt Peak magnetograms as input,
  the authors have determined a best-fit diffusion constant by comparing
  the computed and observed fields at later times. The results suggest
  that diffusion may be fast enough to account for the observed polar
  magnetic field reversal without requiring a significant assist from
  meridional currents.

Title: The observation of a coronal transient directed at Earth.
Authors: Howard, R. A.; Michels, D. J.; Sheeley, N. R., Jr.; Koomen,
   M. J.
Bibcode: 1982ApJ...263L.101H
Altcode:
  The paper reports the observation of a large coronal transient that
  can only be interpreted as a three-dimensional structure. Its form
  is one which has not been observed before: a gradually expanding,
  sun-centered disk of excess brightness, whose projected radius increased
  from 4 to 8 solar radii during 0832-0958 UT on November 27, 1979. This
  earth-directed transient was the source of an interplanetary shock
  wave that reached ISEE 3 at 0649 UT, November 30, and earth at 0738
  UT, November 30. Fitting the shock speed at ISEE 3 and the average
  transit speed from the sun to ISEE 3 to a power law of the form V =
  (V<SUB>0)(r</SUB> exp -n), it is found that V<SUB>0</SUB> = 1980 km/s
  and n = 0.294, in good agreement with shock wave models. The shock
  speed predicted by the power law at 10 solar radii is 1000 km/s,
  in good agreement with the estimated frontal speed of the transient.

Title: A magnetic cloud and a coronal mass ejection
Authors: Burlaga, L. F.; Klein, L.; Sheeley, N. R., Jr.; Michels,
   D. J.; Howard, R. A.; Koomen, M. J.; Schwenn, R.; Rosenbauer, H.
Bibcode: 1982GeoRL...9.1317B
Altcode:
  An interplanetary magnetic cloud observed by the Helios 1 spacecraft
  was found to be associated with a coronal mass ejection observed by the
  NRL Solwind coronagraph on the spacecraft P78-1. The magnetic cloud was
  observed on June 20, 1980 when Helios 1 was at 0.54 AU and nearly 90°
  west of the earth-sun line. This was associated with a large loop-like
  coronal mass ejection observed over the west limb on June 18, 1980,
  moving toward Helios 1. The speed of the front of the event at Helios
  1 was (470 ± 10) km/s, which is close to the mean transit speed (∽
  500 km/s). The magnetic cloud was similar to others described in the
  literature: The magnetic field strength was higher than average; the
  density was relatively low; the magnetic pressure greatly exceeded
  the ion thermal pressure; and the magnetic field direction changed
  through the cloud by rotating parallel to a plane which was highly
  inclined with respect to the ecliptic.

Title: Simultaneous radio scattering and white light observations
    of a coronal transient
Authors: Woo, R.; Armstrong, J. W.; Sheeley, N. R., Jr.; Howard,
   R. A.; Michels, D. J.; Koomen, M. J.
Bibcode: 1982Natur.300..157W
Altcode:
  Reports that a coronal transient observed by the Solwind coronagraph
  off the west limb of the sun was also seen in the spectral broadening
  observations of the Helois-2 2.3 GHz radio signal. These simultaneous
  data are compared and applied to studies of the shock front. UT
  difference images show a time difference of up to 2 h between shock and
  white light occurrences. Helios and Voyager shock speed measurements
  are consistent, implying that the event observed by Helios is a
  shock. These coronal transient data show that the shock front is ahead
  of the white light front, but additional observations of larger events
  will contribute information to the understanding of coronal transient
  evolution as they propagate away from the sun.

Title: Coronagraphic observations of two new sungrazing comets
Authors: Sheeley, N. R., Jr.; Howard, R. A.; Koomen, M. J.; Michels,
   D. J.
Bibcode: 1982Natur.300..239S
Altcode:
  We recently reported the discovery<SUP>1</SUP> of a comet
  (Howard-Koomen-Michels: 1979 XI) that apparently collided with the
  Sun on 30 August 1979. We now report observations of two additional
  sungrazers that encountered the Sun on 27 January 1981 and 20 July 1981,
  respectively. Like comet 1979 XI, these two new comets seem to have
  been members of the Kreutz group of sungrazers<SUP>2-4</SUP>, and like
  1979 XI the new comets did not reappear after their encounters with
  the Sun. The discovery of three previously unreported comets during
  the initial 2.3 yr of our satellite coronal observations leads us to
  suspect that sungrazers are much more common than one might suppose
  from the list of only nine known sungrazers observed during the years
  1668-1970<SUP>5,6</SUP>.

Title: A Model for the Evolution of Large-Scale Magnetic Fields in
    the Solar Photosphere
Authors: DeVore, C. R.; Boris, J. P.; Young, T. R., Jr.; Sheeley,
   N. R., Jr.; Harvey, K. L.
Bibcode: 1982BAAS...14..978D
Altcode:
  No abstract at ADS

Title: Probable Sungrazing Comet
Authors: Michels, D. J.; Sheeley, N.; Harlow, F.; Marsden, B. G.
Bibcode: 1982IAUC.3718....1M
Altcode:
  D. J. Michels, Naval Research Laboratory. reports that continued
  analysis of the P78-l SOLWIND data has revealed a second sungrazing
  comet (cf. IAUC 3640, 3647). The 15 observations below were obtained
  as the comet approached the sun on 1981 Jan. 26-27. The discovery
  team Includes N. Sheeley, 0. Roberts and F. Harlow. Calculations
  at N.R.L. Indicate that the observations are consistent with a
  Kreutz-type orbit and that the comet possibly hit the sun. The object
  brightened from ~ mag 0.0 at 8 solar radii to mag -2.5 or brighter at
  3 solar radii, apparently with a fading to mag +1.0 near 5.5 solar
  radii. Contrary to the situation with the earlier object (comet
  1979 XI), there was this time no evidence of residue from the comet
  after its presumed perihelion passage. 1981 UT rho theta R. A. (1950)
  Decl. Jan. 26.860 8.07 118.0 20 43.40 -19 21.3 26.867 7.87 117.8 20
  43.22 -19 19.8 26.874 7.83 117.6 20 43.22 -19 19.1 26.881 7.63 117.1
  20 43.10 -19 16.9 26.888 7.30 116.8 20 42.74 -19 14.7 26.927 6.12 115.6
  20 41.72 -19 06.4 26.934 5.97 115.3 20 41.66 -19 05.1 26.941 5.93 114.8
  20 41.66 -19 04.1 26.947 5.67 114.0 20 41.42 -19 01.7 26.954 5.41 113.7
  20 41.18 -19 00.0 26.994 4.01 109.7 20 39.92 -18 49.6 27.001 3.71 109.4
  20 39.62 -18 48.4 27.008 3.66 109.0 20 39.62 -18 47.7 27.014 3.40 107.9
  20 39.38 -18 45.9 27.021 3,05 105.6 20 39.02 -18 43.1 The heliocentric
  separations rho are given in units of the instantaneous solar radius,
  and the position angle theta is measured counterclockwise from the
  sun's north pole. The followIng parabolic orbital elements, derived by
  the undersigned on the assumption that the comet's perihelion direction
  agrees with the Kreutz group, satisfy the observations within 2'.5: T =
  1981 Jan. 27.076 ET Peri. = 71.982 Node = 349.967 1950.0 q = 0.00488 AU
  (= 1.05 Rs) Incl. = 142.738

Title: Magnetic measurements of coronal holes during 1975 1980
Authors: Harvey, K. L.; Sheeley, N. R., Jr.; Harvey, J. W.
Bibcode: 1982SoPh...79..149H
Altcode:
  Photospheric magnetic fluxes and average field strengths have been
  measured beneath 33 coronal holes observed on 63 occasions during
  1975-1980. The principal result is that low-latitude holes contained
  3 times more flux near sunspot maximum than near minimum despite the
  fact that their sizes were essentially the same. Average magnetic
  field strengths ranged from 3-36 G near sunspot maximum compared to
  1-7 G near minimum. Evidently the low-latitude coronal holes received
  a proportion of the extra flux that was available at low latitudes
  near sunspot maximum.

Title: The coronal field lines of an evolving bipolar magnetic region
Authors: Sheeley, N. R., Jr.
Bibcode: 1982ApJ...255..316S
Altcode:
  A simple potential field model is presented to illustrate that
  loops of magnetic flux rise upward through the corona during the
  relatively short growth phase of a bipolar magnetic region but contract
  back to the sun's surface during the much longer decay phase of the
  photospheric region. To reconcile this behavior with the unidirectional,
  solar-wind-driven convection of flux outward from the sun, one must
  postulate the existence of an X-type neutral line in the middle corona
  where open field lines can be converted back to closed ones.

Title: Observations of coronal structure during sunspot maximum.
Authors: Sheeley, N. R., Jr.; Howard, R. A.; Koomen, M. J.; Michels,
   D. J.; Harvey, K. L.; Harvey, J. W.
Bibcode: 1982SSRv...33..219S
Altcode:
  This paper presents some of the results that have been obtained from
  the Kitt Peak observations of coronal holes and the NRL observations
  of coronal transients during the recent years near sunspot maximum
  (1979 1981). On the average, low-latitude coronal holes of comparable
  size contained 3 times more flux near sunspot maximum than near the
  previous minimum. In the outer corona, transients occurred at the
  observed rate of at least 2 per day, and quiet conditions persisted
  during less than 15 % of the observed days. We describe a sample of
  the more than 800 events that we have observed so far, including the
  observation of a comet apparently colliding with the Sun.

Title: The observation of a coronal transient directed at earth.
Authors: Michels, D. J.; Howard, R. A.; Koomen, M. J.; Sheeley,
   N. R., Jr.
Bibcode: 1982BAAS...14R.572M
Altcode:
  No abstract at ADS

Title: Observations of a Comet on Collision Course with the Sun
Authors: Michels, D. J.; Sheeley, N. R.; Howard, R. A.; Koomen, M. J.
Bibcode: 1982Sci...215.1097M
Altcode:
  A brilliant new comet (1979 XI: Howard-Koomen-Michels) was discovered
  in data from the Naval Research Laboratory's orbiting SOLWIND
  coronagraph. An extensive sequence of pictures, telemetered from
  the P78-1 satellite, shows the coma, accompanied by a bright and
  well-developed tail, passing through the coronagraph's field of view at
  a few million kilometers from the sun. Preliminary orbital calculations
  based on the observed motion of the comet's head and morphology of the
  tail indicate that this previously unreported object is a sungrazing
  comet and may be one of the group of Kreutz sungrazers. It appears from
  the data that the perihelion distance was less than 1 solar radius,
  so that the cometary nucleus encountered dense regions of the sun's
  atmosphere, was completely vaporized, and did not reappear after the
  time of closest approach to the sun. After this time, however, cometary
  debris, scattered into the ambient solar wind, caused a brightening
  of the corona over one solar hemisphere and to heliocentric distances
  of 5 to 10 solar radii.

Title: Probable Sungrazing Comet
Authors: Howard, R.; Koomen, N.; Michels, D. J.; Sheeley, N.; Marsden,
   B. G.
Bibcode: 1981IAUC.3640....1H
Altcode:
  Images of a probable comet have been found at the Naval Research
  Laboratory, Washington, on coronagraph exposures obtained from
  the satellite P78-1 in 1979. The object was found by R. Howard as
  a result of instrumentation developed and operated by N. Koomen and
  D. J. Michels. The following heliocentric separations rho (in units of
  the instantaneous solar radius) and position angles theta (measured
  counterclockwise from the sun's north pole) have been derived by
  N. Sheeley and converted to R.A. and Decl. by the undersigned. The head
  of the object was somewhat brighter than Venus, and a tail was directed
  roughly away from the center of the sun. 1979 UT rho theta R.A. (1950)
  Decl. Aug. 30.789 5.96 234.2 10 26.47 + 8 45.1 30.796 5.67 233.8 10
  26.80 + 8 45.5 30.802 5.27 234.3 10 27.22 + 8 47.8 30.809 5.16 234.6
  10 27.36 + 8 48.6 30.816 5.09 235.4 10 27.43 + 8 49.8 30.856 3.65 235.7
  10 29.07 + 8 54.8 30.867 3.11 236.1 10 29.67 + 8 56.9 30.885 2.56 239.2
  10 30.28 + 9 00.7 At the last observation the object's head was at the
  edge of the coronagraph's occulting disk. On the next exposure, taken at
  Aug. 30.989 UT, the tail is still present, and during the next several
  hours cometary material evidently diffused around to p.a. ~ 360o. The
  comet's orbit cannot be unequivocally determined, but computations by
  the undersigned suggest that a retrograde solution is to be preferred,
  for this better explains the previous failure to detect the comet in a
  twilit sky. Other possible coronagraphic or hitherto unreported visual
  detections of the object would of course be very useful. Retrograde
  orbit solutions show some resemblance to the orbits of the members
  of the Kreutz sungrazing comet group; there would seem to be a good
  chance that the comet hit the sun (for the head was not detected after
  perihelion). The following possible orbital solution has been selected
  solely because of its general resemblance to the Kreutz-type orbits:
  T = 1979 Aug. 30.92 ET Peri. = 83.42 Node = 9.81 1950.0 q = 0.001 AU
  (assumed) Incl. = 142.42

Title: Coronal holes, solar wind streams, and geomagnetic disturbances
    during 1978 and 1979
Authors: Sheeley, N. R., Jr.; Harvey, J. W.
Bibcode: 1981SoPh...70..237S
Altcode:
  We have extended our long-term study of coronal holes, solar wind
  streams, and geomagnetic disturbances through the rising phase of
  sunspot cycle 21 into the era of sunspot maximum. During 1978 and
  1979, coronal holes reflected the influence of differential rotation,
  and existed within a slowly-evolving large-scale pattern despite the
  relatively high level of sunspot activity. The long-lived 28.5-day
  pattern is not produced by a rigidly-rotating quasi-stationary
  structure on the Sun, but seems to be produced by a non-stationary
  migratory process associated with solar differential rotation. The
  association between coronal holes and solar wind speed enhancements at
  Earth continues to depend on the latitude of the holes (relative to
  the heliographic latitude of Earth), but even the best associations
  since 1976 have speeds of only 500-600 km s<SUP>-1</SUP> rather than
  the values of 600-700 km s<SUP>-1</SUP> that usually occurred during
  the declining phase of sunspot cycle 20.

Title: A Comet on Collision Course with the Sun: Observations on
    August 30-31, 1979
Authors: Howard, R. A.; Koomen, M. J.; Michels, D. J.; Sheeley,
   N. R., Jr.
Bibcode: 1981BAAS...13..875H
Altcode:
  No abstract at ADS

Title: A Comet on Collision Course with the Sun: Orbital Data Deduced
    from the Observations of Aug 30-31, 1979
Authors: Sheeley, N. R., Jr.; Howard, R. A.; Koomen, M. J.; Michels,
   D. J.
Bibcode: 1981BAAS...13..875S
Altcode:
  No abstract at ADS

Title: Coronagraph Observations of a Sun-directed Comet, Aug. 30-31,
1979: Images, Analysis and Photometry
Authors: Koomen, M. J.; Michels, D. J.; Sheeley, N. R., Jr.; Howard,
   R. A.
Bibcode: 1981BAAS...13R.891K
Altcode:
  No abstract at ADS

Title: A Comet on Collision Course with the Sun: Dynamical
    Interpretation of the Observations of Aug 30-31, 1979
Authors: Michels, D. J.; Sheeley, N. R., Jr.; Howard, R. A.; Koomen,
   M. J.
Bibcode: 1981BAAS...13..875M
Altcode:
  No abstract at ADS

Title: A comet on collision course with the sun: orbital data deduced
    from the observations of August 30 - 31, 1979.
Authors: Sheeley, N. R., Jr.; Howard, R. A.; Koomen, M. J.; Michels,
   D. J.
Bibcode: 1981BAAS...13R.875S
Altcode:
  No abstract at ADS

Title: A comet on collision course with the sun: observations on
    August 30 - 31, 1979.
Authors: Sheeley, N. R., Jr.; Howard, R. A.; Koomen, M. J.; Michels,
   D. J.
Bibcode: 1981BAAS...13Q.875S
Altcode:
  No abstract at ADS

Title: The influence of differential rotation on the equatorial
    component of the sun's magnetic dipole field
Authors: Sheeley, N. R., Jr.
Bibcode: 1981ApJ...243.1040S
Altcode:
  This paper examines the effect that solar differential rotation would
  have on a hypothetical large-scale equatorial dipole field. The evolving
  large-scale field pattern is expressed as a series of non-axisymmetric
  moments. As time increases, power is transferred to progressively
  higher order moments. In the 27d rotating coordinate system, each
  moment undergoes a small retrograde drift which remains nearly uniform
  until that mode begins to fade. The synodic rotation periods of the
  first few moments are comparable to the observed 28.5d period of the
  sun's large-scale field near sunspot maximum. Differential rotation
  may be the source of this 28.5d period, but the eruption of new flux
  is necessary to keep the pattern going.

Title: Coronal Transients Near Sunspot Maximum
Authors: Poland, A. I.; Howard, R. A.; Koomen, M. J.; Michels, D. J.;
   Sheeley, N. R., Jr.
Bibcode: 1981SoPh...69..169P
Altcode:
  The Naval Research Laboratory's most recent Earth-orbiting coronagraph,
  called Solwind, has been observing the Sun's outer corona (2.6-10.0
  R<SUB>⊙</SUB>) at 10-min intervals since March 28, 1979. These
  observations provide the first comprehensive view of coronal transients
  near the peak of a sunspot cycle. Six, well-defined transients in
  our quick-look data have masses ranging from 7 × 10<SUP>14</SUP>
  g to 2 × 10<SUP>16</SUP> g and outward speeds ranging from 150 km
  s<SUP>−1</SUP> to 900 km s<SUP>−1</SUP>. These values are comparable
  to the ones that were obtained with the OSO-7 and Skylab observations
  during the declining phase of the last sunspot cycle. Although the
  amount of quick-look data is not sufficient to provide meaningful
  statistics, the coronal transients near sunspot maximum seem to occur
  with a greater frequency and a wider latitude range than the transients
  during the declining phase of the cycle. In both eras, there is a good,
  but imperfect, association between the occurrence of coronal transients
  and surface phenomena such as eruptive prominences and flares.

Title: The overall structure and evolution of active regions.
Authors: Sheeley, N. R., Jr.
Bibcode: 1981sars.work...17S
Altcode:
  The evolutionary characteristics and structure of the magnetic fields
  and atmospheric phenomena associated with the development of a solar
  magnetic region are discussed. Bipolar magnetic regions are introduced
  as the source of all solar magnetic fields, formed as bundles of
  magnetic flux rise to and break through the solar surface and spread
  throughout the photosphere, chromosphere and corona. The photospheric
  magnetic region is shown to be characterized by bipolar flux regions
  of various sizes emerging rapidly for a few days, then expanding and
  decreasing in flux for several months and fragmenting. Sunspots and
  faculae are considered as tracers of the magnetic regions in the upper
  photosphere or lower chromosphere, while chromospheric tracers include
  arch filaments, field transition arches, long chromospheric threads,
  disk filaments and dark fibrils in chromospheric lines. The transition
  region and lower corona exhibit a multithermal plasma distribution,
  with low-temperature plasmas confined to the footprints and legs of
  magnetic field lines and high-temperature plasmas originating in loops
  or systems of unresolved loops. The bipolar magnetic region is also
  shown to interact with its surroundings to produce an interconnected
  field line pattern.

Title: Coronal Evolution and Transients: 1979-1980
Authors: Howard, R. A.; Koomen, M. J.; Sheeley, N. R.; Michels, D. J.
Bibcode: 1980BAAS...12R.898H
Altcode:
  No abstract at ADS

Title: The Solar Origin of An Interplanetary Shock
Authors: Sheeley, N. R., Jr.; Howard, R. A.; Koomen, M. J.; Michels,
   D. J.; Rompolt, B.; Schwenn, R. W.; Mihalov, J. D.
Bibcode: 1980BAAS...12..920S
Altcode:
  No abstract at ADS

Title: Coronal Holes and the Sun's Mean Magnetic Field
Authors: Harvey, K. L.; Sheeley, N. R., Jr.
Bibcode: 1980BAAS...12..918H
Altcode:
  No abstract at ADS

Title: A Three-Coronagraph Record from 1 to 10 R<SUB>O</SUB> of the
    Energetics of a Coronal Transient
Authors: Wagner, W. J.; Sawyer, C.; Illing, R. M. E.; House, L. L.;
   Querfeld, C. W.; Sheeley, N. R., Jr.; Howard, R. A.; Koomen, M. J.;
   Michels, D. J.; Smartt, R. N.
Bibcode: 1980BAAS...12Q.902W
Altcode:
  No abstract at ADS

Title: The equatorial latitude of auroral activity during 1972 1977
Authors: Sheeley, N. R., Jr.; Howard, R. A.
Bibcode: 1980SoPh...67..189S
Altcode:
  The equatorial latitude of auroral activity has been derived from both
  electron and optical observations with the DMSP satellites. Virtually
  all of the observations that were obtained during the 5-year interval
  June 1972-September 1977 have been used to construct a nearly continuous
  plot of invariant geomagnetic latitude versus time.

Title: Recent Satellite Observations of the Corona
Authors: Koomen, M. J.; Sheeley, N. R., Jr.; Michels, D. J.; Howard,
   R. A.
Bibcode: 1980S&T....60..102K
Altcode:
  Observations of the solar corona by the DOD satellite P78-1 are
  discussed and compared with previous findings by OSO-7 and Skylab. The
  satellite carries a coronagraph and several other solar instruments,
  including X-ray spectrometers for analyzing the spectra of solar
  flares and for monochromatic imaging of X-ray emission from active
  regions. Computer analysis of the pictures obtained in a three-day
  span in May 1979 shows that many of the day-to-day changes in the
  streamers result from the rapid ejection of coronal matter, which
  disrupts the streamers and leaves gradually fading structures in their
  place. The findings of P78-1 as well as OSO-7 and Skylab seem to agree
  on a connection between eruptive prominences and coronal transients,
  but the exact nature of the association is not yet clear.

Title: The observation of a high-latitude coronal transient
Authors: Sheeley, N. R., Jr.; Howard, R. A.; Koomen, M. J.; Michels,
   D. J.; Poland, A. I.
Bibcode: 1980ApJ...238L.161S
Altcode:
  On 1979 September 27 NRL's earth-orbiting coronagraph (Solwind)
  observed a coronal mass ejection whose outward direction in the plane
  of the sky was within 12 deg of the sun's north polar axis. Such
  high-latitude transients were not observed by the OSO 7 and Skylab
  coronagraphs during the declining phase of the last sunspot cycle,
  but may be relatively common near sunspot maximum.

Title: Initial observations with the SOLWIND coronagraph
Authors: Sheeley, N. R., Jr.; Michels, D. J.; Howard, R. A.; Koomen,
   M. J.
Bibcode: 1980ApJ...237L..99S
Altcode:
  The NRL Solwind coronagraph has provided the first systematic,
  temporally (10 minute intervals) resolved view of the outer solar
  corona near the peak of a sunspot cycle. It observes a 2.6-10.0 solar
  radii annular field of view with a spatial resolution of 1.25 arc
  min, and the Solwind observations allow the study of the evolution
  of streamers at high latitude for the first time. It is noted that
  most coronal structures changed significantly from day to day, which
  changes were associated with the ejection of material outward across
  the coronagraph's field of view. Attention is given to a transient
  which was observed to have a well-defined curved front which advanced
  outward across the field of view at an essentially constant speed of
  500 km/s, but unlike most Skylab loop-type mass ejections, left no
  remnants 24 hours later.

Title: Temporal Variations of Loop Structures in the Solar Atmosphere
Authors: Sheeley, N. R., Jr.
Bibcode: 1980SoPh...66...79S
Altcode:
  Unique timelapse sequences of Skylab/ATM spectroheliograms reveal the
  following characteristics of normal (i.e. non-flare) loop structures
  in the solar atmosphere: At the 0.5 × 10<SUP>6</SUP> K temperature
  of Ne VII, emission is concentrated into individual spiky structures
  that project 10<SUP>4</SUP>-10<SUP>5</SUP> km from their magnetic
  footpoints and live on the order of 30 min.

Title: Simultaneous Measurement of Coronal Faraday Rotation and
    Total Electron Content During Solar Occultation of PSRO525+21
Authors: Howard, R. A.; Bird, M. K.; Koomen, M. J.; Michels, D. J.;
   Sheeley, N. R., Jr.
Bibcode: 1980BAAS...12..545H
Altcode:
  No abstract at ADS

Title: The evolution of the polar coronal holes
Authors: Sheeley, N. R., Jr.
Bibcode: 1980SoPh...65..229S
Altcode:
  He I 10830 Å synoptic maps, obtained at the Kitt Peak National
  Observatory during 1974-1979, show that the Sun's polar coronal
  holes have contracted significantly during 1977-1978. Prior to the
  accelerated increase of sunspot activity in mid-1977, the area of
  each polar cap was on the order of 8% of the Sun's total surface area
  (4πR<SUP>2</SUP>), whereas toward the end of 1978 these areas fell
  below 2% of 4πR<SUP>2</SUP>. Synoptic polar plots show that the
  vestigual holes had irregular shapes and were often well removed from
  the poles themselves. These results are consistent with the changes
  that one would expect when the polar magnetic fields are weakening
  just prior to sunspot maximum.

Title: Coronal Holes, Solar Wind Streams, and Geomagnetic Disturbances
    During 1978 and 1979
Authors: Sheeley, N. R., Jr.; Harvey, J. W.
Bibcode: 1980BAAS...12R.545S
Altcode:
  No abstract at ADS

Title: The Lateral Expansion of the August 14, 1979 Coronal Transient
Authors: Koomen, M. J.; Michels, D. J.; Howard, R. A.; Sheeley,
   N. R., Jr.
Bibcode: 1980BAAS...12..515K
Altcode:
  No abstract at ADS

Title: The Contraction and Disappearance of the Polar Coronal Holes
Authors: Sheeley, N. R., Jr.
Bibcode: 1980NASCP2098..219S
Altcode: 1980sscs.nasa..219S
  He I 10830 A spectroheliograms obtained during 1974-1979 were used to
  study the evolution of the Sun's polar coronal holes. Synoptic polar
  plots show that the holes have decreased in size to the point that
  only vestigual holes remain and even these remnants fluctuate with
  detailed sunspot activity.

Title: Satellite observations of the outer corona near sunspot maximum
Authors: Michels, D. J.; Howard, R. A.; Koomen, M. J.; Sheeley,
   N. R., Jr.
Bibcode: 1980IAUS...86..439M
Altcode: 1980IAUS...89..439M
  This paper shows the first satellite observations of the Sun's white
  light corona (2.6 R_⊙ - 10.0 R_⊙) during the active phase of a
  sunspot cycle. Since March 28, 1979, these observations have been
  obtained routinely with a spatial resolution of 1.25 arc min and a
  repetition rate of 10 minutes during the one-hour sunlit portion of
  each 97-minute satellite orbital period. As an illustration of these
  new observations, we show the coronal changes associated with the
  great mass of May 8, 1979.

Title: The solar mass ejection of 8 May 1979
Authors: Michels, D. J.; Howard, R. A.; Koomen, M. J.; Sheeley, N. R.,
   Jr.; Rompolt, B.
Bibcode: 1980IAUS...91..387M
Altcode:
  The solar mass ejection of May 8, 1979 is characterized using images
  from the NRL SOLWIND coronagraph on board the P78-1 satellite. The
  eruption of the polar crown filament began at about 0810 UT and reached
  maximum distance of 1.5 solar radii from the center of the sun at 1021
  UT. The eruptive prominence subsequently faded, and some of the material
  fell back to the solar surface. Vestiges of the H-alpha prominence
  disappeared by 1120 UT. The bulk of the prominence material displayed
  radial velocities averaging 40 km/sec with 165 km/sec the maximum
  velocity observed. From 1028 UT to 1246 UT, the leading edge of the
  ejecta moved outward with a constant radial velocity of approximately
  500 km/sec. Projected back to the solar limb, this indicated an onset
  near 0950 UT.

Title: Solar observations with a new earth-orbiting coronagraph
Authors: Sheeley, N. R., Jr.; Howard, R. A.; Michels, D. J.; Koomen,
   M. J.
Bibcode: 1980IAUS...91...55S
Altcode:
  No abstract at ADS

Title: Rapid changes in the fine structure of a coronal "Bright point"
    and a small coronal "active region".
Authors: Sheeley, N. R., Jr.; Golub, L.
Bibcode: 1979SoPh...63..119S
Altcode:
  A coronal `bright point' is resolved into a pattern of emission which,
  at any given time, consists of 2 or 3 miniature loops (each ∼2500
  km in diameter and ∼12 000 km long). During the half-day lifetime
  of the `bright point' individual loops evolved on a time scale ∼6
  min. A small `ctive region' seemed to evolve in this way, but the
  occasional blurring together of several loops made it difficult to
  follow individual changes.

Title: Coronal Holes and Solar Magnetic Fields (Article published in
the special issues: Proceedings of the Symposium on Solar Terrestrial
    Physics held in Innsbruck, May- June 1978. (pp. 137-538))
Authors: Harvey, J. W.; Sheeley, N. R., Jr.
Bibcode: 1979SSRv...23..139H
Altcode:
  Since 1972, nearly continuous observations of coronal holes and their
  associated photospheric magnetic fields have been made using a variety
  of satellite and ground-based equipment. The results of comparisons
  of these observations are reviewed and it is demonstrated that the
  structure and evolution of coronal holes is basically governed by the
  large-scale distribution of photospheric magnetic flux. Non-polar
  holes form in the decaying remnants of bipolar magnetic regions in
  areas with a large-scale flux imbalance. There is strong indirect
  evidence that the magnetic field in coronal holes is always open to
  interplanetary space but not all open-field regions have associated
  coronal holes. The well-observed declining phase of the last solar
  cycle was characterized by stable magnetic field and coronal hole
  patterns which were associated with recurrent, high-speed wind streams
  and interplanetary magnetic field patterns at the Earth. The ascending
  phase of the current cycle has been characterized by transient magnetic
  field and coronal hole patterns which tend to occur at high solar
  latitudes. This shift in magnetic field and coronal hole patterns
  has resulted in a less obvious and more complicated association with
  high-speed wind streams at the Earth.

Title: Comparison of Satellite and Rocket Coronal Observations around
    April 13, 1979
Authors: Howard, R. A.; Michels, D. J.; Koomen, M. J.; Sheeley, N. R.,
   Jr.; Kohl, J. L.; Munro, R. H.; Weiser, H.
Bibcode: 1979BAAS...11..408H
Altcode:
  No abstract at ADS

Title: Discussion
Authors: Anzer, U.; Raadu, M. A.; Rompolt, B.; Rust, D. M.; Sheeley,
   N.; Spicer, D. S.
Bibcode: 1979phsp.coll..171A
Altcode: 1979IAUCo..44..171A
  No abstract at ADS

Title: Discussion
Authors: Engvold, O.; Gaizauskas, Gaizauskas; Rust, D. M.; Sheeley,
   N.; Tandberg-Hanssen, E.; Ohman, Y.; Zirin, H.
Bibcode: 1979phsp.coll..207E
Altcode: 1979IAUCo..44..207E
  No abstract at ADS

Title: Discussion
Authors: Acton, L. W.; Kundu, M. R.; Maltby, P.; Malville, J.; Orrall,
   F. Q.; Sheeley, N.; Spicer, D. S.
Bibcode: 1979phsp.coll..225A
Altcode: 1979IAUCo..44..225A
  No abstract at ADS

Title: Discussion
Authors: Anzer, U.; Chiuderi-Drago, F.; Kundu, M. R.; Leroy, J. L.;
   Malville, J.; Rompolt, B.; Sheeley, N.; Stenflo, J.; Tandberg-Hanssen,
   E.; Öhman, Y.
Bibcode: 1979phsp.coll...77A
Altcode: 1979IAUCo..44...77A
  No abstract at ADS

Title: Coronal holes, solar wind streams, and geomagnetic activity
    during the new sunspot cycle.
Authors: Sheeley, N. R., Jr.; Harvey, J. W.
Bibcode: 1978SoPh...59..159S
Altcode:
  The paper presents results obtained for 1976-1977 using daily He I 10830
  A spectroheliograms and photospheric magnetograms. It was found that as
  the magnetic field patterns changed, the solar atmosphere evolved from
  a structure with a few large long-lived low-latitude coronal holes to
  one with numerous small short-lived high-latitude holes. High-latitude
  holes recurred with a synodic rotation period of 28-29 days instead of
  the 27-day period already known to be characteristic of low-latitude
  holes. A Bartels display of the occurrence of holes, wind speed,
  and geomagnetic activity is considered.

Title: Coronal holes, solar wind streams, and geomagnetic activity
    during the new sunspot cycle
Authors: Harvey, J. W.; Sheeley, N. R.
Bibcode: 1978SoPh...59..159H
Altcode:
  We have extended our previous study of coronal holes, solar wind
  streams, and geomagnetic disturbances from the declining phase
  (1973-1975) of sunspot cycle 20 through sunspot minimum (1976)
  into the rising phase (1977) of cycle 21. Using daily He I 10830
  Å spectroheliograms and photospheric magnetograms, we found the
  following results: As the magnetic field patterns changed, the solar
  atmosphere evolved from a structure having a few, large, long-lived,
  low-latitude coronal holes to one having numerous small, short-lived,
  high-latitude holes (in addition to the polar holes which persisted
  throughout this 5-year interval).

Title: The equatorward extent of auroral activity during 1973 1974
Authors: Sheeley, N. R., Jr.
Bibcode: 1978SoPh...58..405S
Altcode:
  The equatorward boundary of auroral activity during 1973-1974 has
  been derived from DMSP photographs and their associated `auroral
  analysis records'. On a time scale of days, the equatorward position
  of the northern auroral oval varied in phase with the average level of
  geomagnetic activity. In general, this variation was associated with the
  occurrence of solar flares and coronal holes. On a time scale of hours,
  the equatorward position of the oval correlated with the AE index of
  substorm activity and with the strength of the southward component of
  the interplanetary magnetic field.

Title: Coronal Holes, Solar Wind Streams and Geomagnetic Activity
    During the New Solar Cycle.
Authors: Sheeley, N. R.; Harvey, J. W.
Bibcode: 1978BAAS...10Q.461S
Altcode:
  No abstract at ADS

Title: Extreme ultraviolet observations of coronal
    holes. II. Association of holes with solar magnetic fields and a
    model for their formation during the solar cycle.
Authors: Bohlin, J. D.; Sheeley, N. R., Jr.
Bibcode: 1978SoPh...56..125B
Altcode:
  Extreme-ultraviolet Skylab and ground-based solar magnetic field
  data have been combined to study the origin and evolution of coronal
  holes. It is shown that holes exist only within the large-scale
  unipolar magnetic cells into which the solar surface is divided at
  any given time. A well-defined boundary zone usually exists between
  the edge of a hole and the neutral line which marks the edge of its
  magnetic cell. This boundary zone is the region across which a cell
  is connected by magnetic arcades with adjacent cells of opposite
  polarity. Three pieces of observational evidence are offered to
  support the hypothesis that the magnetic lines of force from a hole
  are open. Kitt Peak magnetograms are used to show that, at least on
  a relative scale, the average field strengths within holes are quite
  variable, but indistinguishable from the field strengths in other
  quiet parts of the Sun's surface.

Title: A survey of coronal holes and their solar wind associations
    throughout sunspot cycle 20.
Authors: Broussard, R. M.; Sheeley, N. R., Jr.; Tousey, R.; Underwood,
   J. H.
Bibcode: 1978SoPh...56..161B
Altcode:
  To gain insight into the relationships between solar activity, the
  occurrence and variability of coronal holes, and the association of
  such holes with solar wind features such as high-velocity streams,
  a study of the period 1963-1974 was made. This period corresponds
  approximately with sunspot cycle 20. The primary data used for this
  work consisted of X-ray and XUV solar images obtained from rockets. The
  investigation revealed that: The polar coronal holes prominent at solar
  minimum, decreased in area as solar activity increased and were small
  or absent at maximum phase. This evolution exhibited the same phase
  difference between the two hemispheres that was observed in other
  indicators of activity.

Title: A comparison of He  ii 304 Å and He  i 10 830 Å
    spectroheliograms
Authors: Harvey, J. W.; Sheeley, N. R., Jr.
Bibcode: 1977SoPh...54..343H
Altcode:
  Spectroheliograms were obtained simultaneously in the He II 304 Å
  emission line and the He I 10 830 Å absorption line with an angular
  resolution of approximately 5″. A negative print of the 304 Å
  image is matched with a positive print of the 10 830 Å image so that
  corresponding features of the chromospheric network (including active
  regions) appear identical in the two images. Differences between these
  images include the facts that: Disk filaments and limb darkening are
  strongly visible in the 10 830 Å positive image, but they are weakly
  visible (as lightenings) in the 304 Å negative image.

Title: A pictorial comparison of interplanetary magnetic field
    polarity, solar wind speed, and geomagnetic disturbance index during
    the sunspot cycle.
Authors: Sheeley, N. R., Jr.; Asbridge, J. R.; Bame, S. J.; Harvey,
   J. W.
Bibcode: 1977SoPh...52..485S
Altcode:
  Observations of interplanetary magnetic field polarity, solar wind
  speed, and geomagnetic disturbance index (C9) during the years
  1962-1975 are compared in a 27-day pictorial format that emphasizes
  their associated variations during the sunspot cycle. This display
  accentuates graphically several recently reported features of solar
  wind streams including the fact that the streams were faster, wider,
  and longer-lived during 1962-1964 and 1973-1975 in the declining
  phase of the sunspot cycle than during intervening years (Bame et al.,
  1976; Gosling et al., 1976). The display reveals strikingly that these
  high-speed streams were associated with the major, recurrent patterns
  of geomagnetic activity that are characteristic of the declining
  phase of the sunspot cycle. Finally, the display shows that during
  1962-1975 the association between long-lived solar wind streams and
  recurrent geomagnetic disturbances was modulated by the annual variation
  (Burch, 1973) of the response of the geomagnetic field to solar wind
  conditions. The phase of this annual variation depends on the polarity
  of the interplanetary magnetic field in the sense that negative sectors
  of the interplanetary field have their greatest geomagnetic effect in
  northern hemisphere spring, and positive sectors have their greatest
  effect in the fall. During 1965-1972 when the solar wind streams
  were relatively slow (500 km s<SUP>-1</SUP>), the annual variation
  strongly influenced the visibility of the corresponding geomagnetic
  disturbance patterns.

Title: Analysis of Solar-Flare Plasmas Using EUV and X-Ray Data.
Authors: Tandberghanssen, E.; Sheeley, N.; Smith, J. B.
Bibcode: 1977BAAS....9..311T
Altcode:
  No abstract at ADS

Title: Observations During the Impulsive Phase of the August 7,
    1973, Solar Flare.
Authors: Sheeley, N. R., Jr.; Kane, S. R.; Vorpahl, J. A.; Chapman,
   G. A.
Bibcode: 1977BAAS....9..311S
Altcode:
  No abstract at ADS

Title: A Comparison of He II 304 Å and He I 10830 Å
    Spectroheligrams.
Authors: Harvey, J. W.; Sheeley, N. R., Jr.
Bibcode: 1977BAAS....9..325H
Altcode:
  No abstract at ADS

Title: An improved measurement of a spectrogram of a "gap".
Authors: Chapman, G. A.; Sheeley, N. R., Jr.
Bibcode: 1977SoPh...51...61C
Altcode:
  A spectrogram of the 5250 Å region previously obtained during a period
  of excellent seeing has been remeasured and calibrated by reference
  to the preliminary KPNO photometric atlas. This analysis, using the
  logarithm of opacitance instead of an H-D plot, has reduced some of
  the effects of scattered light and shows greater facular line contrast.

Title: Observations of Coronal Holes Throughout Sunspot Cycle 20.
Authors: Broussard, R. M.; Underwood, J. H.; Tousey, R.; Sheeley,
   N. R., Jr.
Bibcode: 1976BAAS....8..557B
Altcode:
  No abstract at ADS

Title: Coronal holes, solar wind streams, and recurrent geomagnetic
disturbances: 1973 1976
Authors: Sheeley, N. R., Jr.; Harvey, J. W.; Feldman, W. C.
Bibcode: 1976SoPh...49..271S
Altcode:
  Observations of coronal holes, solar wind streams, and geomagnetic
  disturbances during 1973-1976 are compared in a 27-day pictorial format
  which shows their long-term evolution. The results leave little doubt
  that coronal holes are related to the high-speed streams and their
  associated recurrent geomagnetic disturbances. In particular, these
  observations strongly support the hypothesis that coronal holes are
  the solar origin of the high-speed streams observed in the solar wind
  near the ecliptic plane.

Title: High-latitude observations of solar wind streams and coronal
    holes
Authors: Ricket, B. J.; Sime, D. G.; Crockett, W. R.; Tousey, R.;
   Sheeley, N. R., Jr.
Bibcode: 1976JGR....81.3845R
Altcode:
  Interplanetary scintillation observations of the solar wind velocity
  during 1973 and the first part of 1974 reveal several corotating
  high-speed streams. These streams, of heliographic latitudes from +40°
  to -60°, have been mapped back to the vicinity of the sun and have been
  compared with coronal holes identified in wide band XUV solar images
  taken during the manned portions of the Skylab mission. There is some
  evidence that the high-speed streams are preferentially associated with
  coronal holes and that they can spread out from the hole boundaries
  up to about 20° in latitude. However, this association is not one
  to one; streams are observed which do not map back to coronal holes,
  and holes are observed which do not lie at the base of streams. To the
  extent that a statistical interpretation is possible the association
  is not highly significant, but individual consideration of streams and
  holes suggests that the statistical result is biased somewhat against
  a strong correlation.

Title: Polar faculae during the interval 1906-1975
Authors: Sheeley, N. R., Jr.
Bibcode: 1976JGR....81.3462S
Altcode:
  In a previous study (Sheeley, 1964, 1966) the numbers of faculae at
  the poles of the sun were counted and used to estimate the strengths
  of the polar magnetic fields during the period 1906-1964. The present
  paper extends this study to include the recent period 1964-1975. The
  new observations show the following: (1) The polar fields are stronger
  now than they have been for a decade. At the south pole, most of this
  increase in strength occurred in 1973 during the Skylab mission. At
  the north pole the change occurred gradually during 1972 and 1973. (2)
  Except for a relatively brief interval during 1959 the south polar
  field has been weaker during the last magnetic cycle than it has been
  during any cycle since this uniform set of observations began at Mount
  Wilson in 1906.

Title: Energy released by the interaction of coronal magnetic fields.
Authors: Sheeley, N. R., Jr.
Bibcode: 1976SoPh...47..173S
Altcode:
  Comparisons between coronal spectroheliograms and photospheric
  magnetograms are presented to support the idea that as coronal magnetic
  fields interact, a process of field line reconnection usually takes
  place as a natural way of preventing magnetic stresses from building
  up in the lower corona. This suggests that the energy which would have
  been stored in stressed fields is continuously released as kinetic
  energy of material being driven aside to make way for the reconnecting
  fields. However, this kinetic energy is negligible compared to the
  thermal energy of the coronal plasma. Therefore, it appears that these
  slow adjustments of coronal magnetic fields cannot account for even the
  normal heating of the corona, much less the energetic events associated
  with solar flares.

Title: Coronal Changes Associated with a Disappearing Filament
Authors: Sheeley, N. R., Jr.; Bohlin, J. D.; Brueckner, G. E.; Purcell,
   J. D.; Scherrer, V. E.; Tousey, R.; Smith, J. B., Jr.; Speich, D. M.;
   Tandberg Hanssen, E.; Wilson, R. M.; de Loach, A. C.; Hoover, R. B.;
   McGuire, J. P.
Bibcode: 1975SoPh...45..377S
Altcode:
  This paper describes Skylab/ATM observations of the events associated
  with a disappearing filament near the center of the solar disk on
  January 18, 1974. As the filament disappeared, the nearby coronal
  plasma was heated to a temperature in excess of 6 × 10<SUP>6</SUP>K. A
  change in the pattern of coronal emission occurred during the 11/3 hr
  period that the soft X-ray flux was increasing. This change seemed to
  consist of the formation and apparent expansion of a loop-like coronal
  structure which remained visible until its passage around the west limb
  several days later. The time history of the X-ray and microwave radio
  flux displayed the well-known gradual-rise-and-fall (GRF) signature,
  suggesting that this January 18 event may have properties characteristic
  of a wide class of X-ray and radio events.

Title: The Calculation of Force-Free Fields from Discrete Flux
    Distributions
Authors: Sheeley, N. R., Jr.; Harvey, J. W.
Bibcode: 1975SoPh...45..275S
Altcode:
  This paper presents particularly simple mathematical formulas for the
  calculation of force-free fields of constant α from the distribution
  of discrete sources on a flat surface. The advantage of these formulas
  lies in their physical simplicity and the fact that they can be easily
  used in practice to calculate the fields. The disadvantage is that they
  are limited to fields of `sufficiently small α'. These formulas may be
  useful in the study of chromospheric magnetic fields by the comparison
  of high-resolution Hα photographs and photospheric magnetograms.

Title: Skylab/ATM Observations of Transient Events Having the GRF
    X-Ray and Microwave Character.
Authors: Sheeley, N. R., Jr.; Bohlin, J. D.; Scherrer, V. E.;
   Tousey, R.
Bibcode: 1975BAAS....7..429S
Altcode:
  No abstract at ADS

Title: The Sun's Polar Caps as Coronal Holes: Their Sizes, Evolution,
    and Phenomenology During the Skylab Mission.
Authors: Bohlin, J. D.; Rubenstein, D. M.; Sheeley, N. R., Jr.
Bibcode: 1975BAAS....7..457B
Altcode:
  No abstract at ADS

Title: X-Ray Event of August 13-15, 1973.
Authors: Scherrer, V.; Sandlin, G.; Sheeley, N.; Tousey, R.
Bibcode: 1975BAAS....7..430S
Altcode:
  No abstract at ADS

Title: A newly observed solar feature: macrospicules in He II 304 Å.
Authors: Bohlin, J. D.; Vogel, S. N.; Purcell, J. D.; Sheeley, N. R.,
   Jr.; Tousey, R.; Vanhoosier, M. E.
Bibcode: 1975ApJ...197L.133B
Altcode:
  He II 304 A spectroheliograms, obtained with the NRL extreme-ultraviolet
  slitless spectrograph during the Skylab mission, show spikelike
  structures at the sun's polar limb which resemble the familiar
  H-alpha spicules. However, the relatively large size and long life
  of these He II features has led to distinguishing them by the name
  'macrospicules'. The macrospicules appear as protuberances or jets,
  ranging from 5 to over 60 sec in length, from 5 to 30 sec in width,
  and from 5 to over 40 minutes in lifetime. Perhaps the most radical
  departure from H-alpha spicules is that macrospicules occur only within
  the chromospheric boundaries of coronal holes. Thus macrospicules
  are most easily visible over the solar poles due to the coronal holes
  normally present there, and much less frequently at lower latitudes
  during limb passage of relatively rare, low-latitude coronal holes.

Title: Polar Plumes in XUV Emission-Line Corona
Authors: Bohlin, J. D.; Purcell, J. D.; Sheeley, N. R., Jr.; Tousey, R.
Bibcode: 1975BAAS....7..356B
Altcode:
  No abstract at ADS

Title: Macro-Spicules in He II 304 Å Over the Sun's Polar Cap
Authors: Bohlin, J. D.; Vogel, S. N.; Purcell, J. D.; Sheeley, N. R.;
   Tousey, R.; van Hoosier, M. E.
Bibcode: 1975BAAS....7R.354B
Altcode:
  No abstract at ADS

Title: The High-Energy Limb Event of January 17, 1974
Authors: Tousey, R.; Bohlin, J. D.; Moe, O. K.; Purcell, J. D.;
   Sheeley, N. R.
Bibcode: 1975BAAS....7..348T
Altcode:
  No abstract at ADS

Title: The reconnection of magnetic field lines in the solar corona.
Authors: Sheeley, N. R., Jr.; Bohlin, J. D.; Brueckner, G. E.; Purcell,
   J. D.; Scherrer, V. E.; Tousey, R.
Bibcode: 1975ApJ...196L.129S
Altcode:
  Skylab XUV coronal spectroheliograms and photospheric magnetograms
  are compared. This comparison shows that, as new bipolar magnetic
  fields emerge through the solar surface into the corona, the new
  coronal fields interact with the old ones in a manner that suggests
  the reconnection of the field lines.

Title: Interpreting XUV Spectroheliograms in Terms of Coronal Magnetic
    Field Structures
Authors: Sheeley, N. R., Jr.; Bohlin, J. D.; Brueckner, G. E.; Purcell,
   J. D.; Scherrer, V. E.; Tousey, R.
Bibcode: 1975BAAS....7Q.346S
Altcode:
  No abstract at ADS

Title: XUV Observations of Coronal Magnetic Fields
Authors: Sheeley, N. R., Jr.; Bohlin, J. D.; Brueckner, G. E.; Purcell,
   J. D.; Scherrer, V.; Tousey, R.
Bibcode: 1975SoPh...40..103S
Altcode:
  Spectroheliograms obtained with the Naval Research Laboratory's
  Extreme Ultraviolet Spectrograph (S082A) on Skylab are compared with
  Kitt Peak National Observatory magnetograms. A principal result is
  the characteristic reconnection of flux from an emerging bipolar
  magnetic region to previously existing flux in its vicinity. Examples
  of the disappearance of magnetic flux from the solar atmosphere are
  also shown. The results of a particularly simple, potential field
  calculation are shown for comparison with the Skylab observations.

Title: Structure of the sun's polar cap at wavelengths 240 - 600 Å.
Authors: Bohlin, J. D.; Sheeley, N. R.; Tousey, R.
Bibcode: 1975spre.conf..651B
Altcode:
  No abstract at ADS

Title: The 1175 Å to 1900 Å Ultraviolet Spectrum of Solar Flares
Authors: Brueckner, G. E.; Bohlin, J. D.; Moe, O. K.; Nicolas, K. R.;
   Purcell, J. D.; Scherrer, V. E.; Sheeley, N. R., Jr.; Tousey, R.
Bibcode: 1974BAAS....6..285B
Altcode:
  No abstract at ADS

Title: A Preliminary Study of Coronal Structures by Means of
    Time-Lapse Photography
Authors: Sheeley, N. R.; Bohlin, J. D.; Brueckner, G. E.; Purcell,
   J. D.; Scherrer, V.; Tousey, R.
Bibcode: 1974BAAS....6Q.294S
Altcode:
  No abstract at ADS

Title: Cinematographic Observations for ATM and their Comparison
    with some ATM Results
Authors: Zirin, H.; Holt, J.; Brueckner, G. E.; Bohlin, J. D.; Purcell,
   J. D.; Scherrer, V. E.; Sheeley, N. R.; Tousey, R.
Bibcode: 1974BAAS....6R.298Z
Altcode:
  No abstract at ADS

Title: Preliminary Results from the Nrl/atm Instruments from
    SKYLAB SL/2
Authors: Tousey, R.; Bartoe, J. D. F.; Bohilin, J. D.; Brueckner,
   G. E.; Purcell, J. D.; Scherrer, V. E.; Schumacher, R. J.; Sheeley,
   N. R.; Vanhoosier, M. E.
Bibcode: 1974IAUS...57..491T
Altcode:
  No abstract at ADS

Title: The eruptive prominence of August 21, 1973 observed from
    Skylab in the white light corona and in the He II 304 Å chromosphere.
Authors: Poland, A. I.; Bohlin, J. D.; Brueckner, G. E.; Purcell,
   J. D.; Scherrer, V. E.; Sheeley, N. R.; Tousey, R.
Bibcode: 1974BAAS....6..219P
Altcode:
  No abstract at ADS

Title: The Eruptive Prominence of August 21, 1973 Observed from
    Skylab in the White Light Corona and in the He II 304Å Chromosphere.
Authors: Poland, A. I.; Bohlin, J. D.; Brueckner, G. E.; Purcell,
   J. D.; Scherrer, V. E.; Sheeley, N. R.; Tousey, R.
Bibcode: 1974BAAS....6..220P
Altcode:
  No abstract at ADS

Title: A Preliminary Study of the Extreme Ultraviolet
    Spectroheliograms from Skylab
Authors: Tousey, R.; Bartoe, J. D. F.; Bohlin, J. D.; Brueckner, G. E.;
   Purcell, J. D.; Scherrer, V. E.; Sheeley, N. R., Jr.; Schumacher,
   R. J.; Vanhoosier, M. E.
Bibcode: 1973SoPh...33..265T
Altcode:
  Some of the first observations obtained with the Naval Research
  Laboratory's Extreme Ultraviolet Spectrograph (S082A) during the first
  Skylab mission are presented and compared with magnetograms and other
  ground-based data. The instrument is a slitless objective-type grating
  spectrograph covering 170-630 Å and described in Solar Phys.27, 251
  (1972). Chromospheric network, loop prominences, active regions,
  a flare, limb brightening, XUV bright points, and `coronal holes'
  are among the phenomena shown and discussed.

Title: Magnetic Outflow - A Stage in the Development of an Active
    Region
Authors: Allen, R.; Edberg, S.; Labonte, B.; Sheeley, N. R.
Bibcode: 1973BAAS....5Q.268A
Altcode:
  No abstract at ADS

Title: Observations of the Horizontal Velocity Field Surrounding
    Sunspots
Authors: Sheeley, N. R., Jr.
Bibcode: 1972SoPh...25...98S
Altcode:
  During the summer and fall of 1971, Doppler spectroheliograms were
  obtained for several sunspots located near the solar limb. These
  observations confirm a previous result based on the study of only a
  few sunspots that in the plage-free photosphere surrounding sunspots
  the spatially-averaged, horizontal flow tends to be outward at 0.5-1.0
  km s<SUP>−1</SUP> for distances typically 10000-20000 km beyond the
  outer boundary of the penumbra. It is suggested that these material
  motions are the means by which small-scale fragments of magnetic flux
  are carried away from sunspots.

Title: The Photospheric Velocity Field in and Around Sunspots
Authors: Sheeley, N. R., Jr.
Bibcode: 1972BAAS....4Q.391S
Altcode:
  No abstract at ADS

Title: Time behavior of Ca  ii K<SUB>2v </SUB> spectral features in
    non-magnetic regions of the solar disk
Authors: Liu, S. Y.; Sheeley, N. R.; Smith, Elske V. P., Jr.
Bibcode: 1972SoPh...23..289L
Altcode:
  No abstract at ADS

Title: New Observations of Solar Magnetic and Brightness Fields
Authors: Sheeley, N. R., Jr.; Liu, S. Y.
Bibcode: 1972lfpm.conf..285S
Altcode:
  No abstract at ADS

Title: A comparison of the intensity variations of the CN photospheric
    and K line chromospheric network with time
Authors: Liu, S. Y.; Sheeley, N. R., Jr.
Bibcode: 1971SoPh...20..282L
Altcode:
  No abstract at ADS

Title: Using CN λ 3883 spectroheliograms to map weak photospheric
    magnetic fields
Authors: Sheeley, N. R., Jr.
Bibcode: 1971SoPh...20...19S
Altcode:
  By photographically averaging time sequences of high-resolution CN λ
  3883 spectroheliograms, the noise level due to the rapidly fluctuating
  intensity of the solar background has been reduced significantly. Very
  faint faculae that are lost in the noise on a single frame are easily
  visible on such an enhanced picture. A comparison between these
  enhanced spectroheliograms and a photoelectric magnetogram suggests
  that the brightness-magnetic field correlation extends to much weaker
  field strengths and fainter faculae than can be detected on a single,
  high quality CN λ 3883 spectroheliogram.

Title: Two-Dimensional Observations of the Velocity Fields in and
    around Sunspots
Authors: Sheeley, N. R., Jr.; Bhatnagar, A.
Bibcode: 1971SoPh...19..338S
Altcode:
  Doppler spectroheliograms of sunspots and their surroundings have
  been obtained with a spatial resolution approaching one second
  of arc and a time resolution of 20 s per frame. Observations of 5
  sunspots, located 18°, 45°, 56°, 60° and 72° from the disk center
  respectively, showed considerable long-lived fine structure and, in
  particular, indicated the following: The Evershed outflow terminated
  in spoke-like structures that constitute the ragged outer boundary of
  the penumbra. Some of these spokes extended more than 8000 km beyond
  the average outer boundary.

Title: Measurements of the Oscillatory and Slowly-Varying Components
    of the Solar Velocity Field
Authors: Sheeley, N. R., Jr.; Bhatnagar, A.
Bibcode: 1971SoPh...18..379S
Altcode:
  Spectroheliograms with high spatial resolution are presented to
  illustrate the decomposition of the solar velocity field into its
  oscillatory and slowly-varying components. An analysis of data obtained
  in the lines FEIλ 5434 and FeIIλ 4924 yield essentially the same
  principal results: Spectroheliograms of the oscillatory component
  have a mottled appearance of rising and falling elements ranging from
  2000 km to 3000 km in size. These elements oscillate vertically with
  a period in the range 275-300 s and an amplitude of 0.5 km/s. Although
  most oscillations last two cycles some have been observed for as many
  as four cycles.

Title: The Reduction of the Solar Velocity Field into Its Oscillatory
    and Slowly-Varying Components
Authors: Sheeley, N. R., Jr.; Bhatnagar, A.
Bibcode: 1971SoPh...18..195S
Altcode:
  Spectroheliogram movies of the solar velocity field have been made in
  the λ4924 line of FeII with a time resolution of 20 sec/frame and a
  spatial resolution in the range 1-2 sec of arc. A conventional doppler
  movie has been used to generate two additional movies which show
  the slowly-varying and oscillatory components of the velocity field
  separately. A basic result is the simplicity of the field patterns
  into which the relatively complex velocity field can be decomposed.

Title: The Time Dependence of Magnetic, Velocity and Intensity Fields
    in the Solar Atmosphere
Authors: Sheeley, N. R., Jr.
Bibcode: 1971IAUS...43..310S
Altcode:
  No abstract at ADS

Title: Simultaneous Measurements of Magnetic Fields and Brightness
    Fields Using a 4-Image Spectroheliograph
Authors: Sheeley, N. R., Jr.; Engvold, O.
Bibcode: 1970SoPh...12...69S
Altcode:
  The use of an auxiliary beamsplitter with the Kitt Peak 15-foot
  spectroheliograph permits spectroheliograms to be taken simultaneously
  in 4 identical images of the sun. By using two of these images
  for a Zeeman spectroheliogram, a third image for a FeI λ4071
  spectroheliogram, and the fourth image for a 6107Å continuum
  spectroheliogram, simultaneous measurements of magnetic fields and
  brightness fields have been obtained. Within the limits of intensity
  variations imposed by doppler shifts and brightness fluctuations
  of the continuum, a quantitative relation does exist between the
  measured values of brightness and magnetic field strength of the
  photospheric network. For intensities measured +0.12 Å from the core
  of FeI λ4071, this relation is ln(1 +ΔI/I) = α¦B<SUB>∥</SUB>¦,
  whereB<SUB>∥</SUB> refers to the component of magnetic field normal to
  the solar surface,ΔI/I is the fractional excess of brightness of the
  magnetic regions relative to the brightness of non-magnetic regions,
  and α = (6±2)%/100 gauss.

Title: The Evolution of the Photospheric Network
Authors: Sheeley, N. R., Jr.
Bibcode: 1969SoPh....9..347S
Altcode:
  A time-lapse sequence of spectroheliograms in the bandhead of CN at
  λ3883 reveals the following behavior of the photospheric network
  with time: There is a steady flow of bright `points' (≃ 1000 km in
  diameter) laterally outward from sunspots at speeds on the order of 1
  km.sec<SUP>−1</SUP>. After traveling about 10 000 km from a sunspot
  they either conglomerate to form fragments of the photospheric network
  or disappear.

Title: Spectroheliograms in Fe II λ4924
Authors: Sheeley, N. R., Jr.; Engvold, O.
Bibcode: 1969BAAS....1T.292S
Altcode:
  No abstract at ADS

Title: The Photospheric Network
Authors: Chapman, G. A.; Sheeley, N. R., Jr.
Bibcode: 1968SoPh....5..442C
Altcode:
  Spectroheliograms, obtained in certain Fraunhofer lines with the
  82-cm solar image at the Kitt Peak National Observatory, show a bright
  photospheric network having the following properties: It resembles,
  but does not coincide with, the chromospheric network, the structure
  of the photospheric network being finer and more delicate than the
  relatively coarse structure of the chromospheric network.

Title: Correlations Between Brightness Fields and Magnetic Fields
    on the Sun
Authors: Chapman, G. A.; Sheeley, N. R., Jr.
Bibcode: 1968IAUS...35..161C
Altcode:
  No abstract at ADS

Title: Observations of Small-Scale Solar Magnetic Fields
Authors: Sheeley, N. R., Jr.
Bibcode: 1967SoPh....1..171S
Altcode:
  Spectrograms, obtained during moments of good seeing with the high
  spatial resolution afforded by the 80-cm solar image at the Kitt Peak
  National Observatory, show the following: Magnetic fields of several
  hundred gauss occur in tiny areas easily as small as 500 km in extent
  in regions of the solar surface sometimes well removed from areas of
  sunspot activity.

Title: The Average Profile of the Solar K-Line during the Sunspot
    Cycle
Authors: Sheeley, N. R., Jr.
Bibcode: 1967ApJ...147.1106S
Altcode:
  Measurements of the fraction of the solar disk covered by bright
  K2 emission at various phases of the sunspot cycle are presented
  together with measurements of the K2 emission intensity of various
  solar features. It is estimated that at the time of the last sunspot
  maximum approximately 20 per cent of the visible disk was covered by
  K2 emission with intensity at least three times that of the quiet
  disk. This corresponds to a 40 per cent increase in the average
  intensity of K2 emission at the time of sunspot maximum over the
  average intensity at the time of sunspot minimum. A smaller variation
  associated with solar rotation is alsd estimated. Average K-spectra
  for the separate hemispheres of the Sun, as they currently appear,
  are presented. These spectra show considerable differences which are
  attributed to the differences in solar activity presently existing in
  the two hemispheres. It is concluded that, if one regards the Sun as a
  point source of light, as it would appear from the vicinity of a distant
  star, there would be a significant variation in the intensity of its
  K2 emission with time corresponding to the variation of the sunspot
  number with time. This result emphasizes the possibility of finding
  "sunspot cycles" in stars by observing the intensity of K2 emission.

Title: Measurements of Solar Magnetic Fields
Authors: Sheeley, N. R., Jr.
Bibcode: 1966ApJ...144..723S
Altcode:
  Using the photographic technique of Leighton, high spatial resolution
  measurements of photospheric magnetic fields have been obtained
  with the following chief results: 1. Regarding sunspot groups as
  sources of magnetic flux and defining a "source flux" that may be
  determined uniquely for a sunspot group from flux measurements, we
  found a variation in source fluxes from group to group ranging from
  less than 0.2 SFU (1 SFU [solar flux unit] = 1021 maxwells) for very
  "small" spot groups to more than 20 SFU for very "large" groups. This
  variation of source flux with sunspot group "size" is described by
  the rule-of-thumb = 1.2 Am, where is the source flux in SFU and Am
  is the group size in 1018 cm2 defined as the maximum area attained
  by the sunspot group during its development. 2. Zeeman photographs
  emphasize that as a bipolar magnetic region (BMR) develops in time and
  as its magnetic flux spreads over a progressively larger area, the flux
  density does not decrease smoothly from the vicinity of the source to
  the outer limit of detectable flux but is distributed in successively
  smaller bits and fragments. Moreover, measurements obtained from these
  Zeeman photographs reveal magnetic field strengths of 200-700 gauss in
  these bits and fragments, showing that fields of a few hundred gauss
  are not uncommon for small magnetic features even in quiet regions
  of the Sun. 3. Numbers of polar faculae have been calibrated to give
  magnetic flux on the polar caps of the Sun as a function of time during
  the period 1905-1964. The fluxes vary cyclicly with time approximately
  90 out of phase with the variation of the sunspot number for the whole
  solar disk with time during the same period (provided the sunspot
  number is given a polarity corresponding to the magnetic polarity
  of the following sunspots of the relevant hemisphere). The maxima of
  the polar fluxes vary considerably from cycle to cycle (just as the
  maxima of the sunspot number vary considerably from cycle to cycle),
  maximum fluxes ranging from 6 to 21 SFU, with 12 SFU being a typical
  maximum polar flux during 1905-1964. These results are consistent with
  the hypothesis that emerging BMR's are the sources of all the flux on
  the solar surface, and that the random walk plus differential rotation
  is the dominant mechanism for the distribution of the flux provided
  by these sources. More important, these measurements provide a means
  of testing this hypothesis in more detail than has been possible
  heretofore.

Title: Measurements of Solar Magnetic Fields.
Authors: Sheeley, Neil Rolfson, Jr.
Bibcode: 1965PhDT.........4S
Altcode:
  No abstract at ADS

Title: Polar Faculae during the Sunspot Cycle.
Authors: Sheeley, Neil R., Jr.
Bibcode: 1964ApJ...140..731S
Altcode:
  The numbers of north and south polar faculae have been counted for the
  period 1935-1963. The chief result is a variation of the numbers of
  polar faculae with time, approximately 180 out of phase with the time
  variation of the sunspot number for the whole solar disk. If the number
  of polar faculae and sunspot number both are plotted versus time with
  "polarities," the important feature appears that the numbers of polar
  faculae lag behind the sunspot number by approximately 90 . This is
  consistent with the supposition (Leighton 1963, 1964) that the sunspots
  provide a source of magnetic flux which is carried to the poles in a
  few years' time by means of a random-walk process associated with the
  convective supergranulation (Leighton, Noyes, and Simon 1962; Simon
  1963) Comparison between the numbers of polar facuiae and measurements
  of the polar magnetic field since 1952 (Babcock 1961; Howard 1963)
  suggests that the past observations of polar faculae can be used to
  extend measurements of polar magnetic field prior to 1952.

