Author name code: katsukawa
ADS astronomy entries on 2022-09-14
author:"Katsukawa, Yukio" 
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Title: Development of Fast and Precise Scan Mirror Mechanism for an
    Airborne Solar Telescope
Authors: Oba, Takayoshi; Shimizu, Toshifumi; Katsukawa, Yukio; Kubo,
   Masahito; Kawabata, Yusuke; Hara, Hirohisa; Uraguchi, Fumihiro;
   Tsuzuki, Toshihiro; Tamura, Tomonori; Shinoda, Kazuya; Kodeki,
   Kazuhide; Fukushima, Kazuhiko; Morales Fernández, José Miguel;
   Sánchez Gómez, Antonio; Balaguer Jimenéz, María; Hernández
   Expósito, David; Gandorfer, Achim
Bibcode: 2022arXiv220713864O
Altcode:
  We developed a scan mirror mechanism (SMM) that enable a slit-based
  spectrometer or spectropolarimeter to precisely and quickly map
  an astronomical object. The SMM, designed to be installed in the
  optical path preceding the entrance slit, tilts a folding mirror
  and then moves the reflected image laterally on the slit plane,
  thereby feeding a different one-dimensional image to be dispersed by
  the spectroscopic equipment. In general, the SMM is required to scan
  quickly and broadly while precisely placing the slit position across
  the field-of-view (FOV). These performances are highly in demand for
  near-future observations, such as studies on the magnetohydrodynamics of
  the photosphere and the chromosphere. Our SMM implements a closed-loop
  control system by installing electromagnetic actuators and gap-based
  capacitance sensors. Our optical test measurements confirmed that the
  SMM fulfils the following performance criteria: i) supreme scan-step
  uniformity (linearity of 0.08%) across the wide scan range (${\pm}$1005
  arcsec), ii) high stability (3${\sigma}$ = 0.1 arcsec), where the
  angles are expressed in mechanical angle, and iii) fast stepping speed
  (26 ms). The excellent capability of the SMM will be demonstrated
  soon in actual use by installing the mechanism for a near-infrared
  spectropolarimeter onboard the balloon-borne solar observatory for
  the third launch, Sunrise III.

Title: Polarimetric calibration of the Sunrise UV Spectropolarimeter
    and Imager
Authors: Iglesias, F. A.; Feller, A.; Gandorfer, A.; Lagg, A.;
   Riethmüller, T. L.; Solanki, S. K.; Katsukawa, Y.; Kubo, M.;
   Zucarelli, G.; Sanchez, M.; Sunrise Team
Bibcode: 2022BAAA...63..305I
Altcode:
  Sunrise is an optical observatory mounted in a stratospheric balloon,
  developed to study magnetic fields in the solar atmosphere with very
  high resolution. In its third flight, Sunrise carry the Sunrise UV
  Spectropolarimeter and Imager (SUSI), that operates in the 313-430 nm
  range, covering thousands of spectral lines not accessible from the
  ground and thus largely unexplored. SUSI does not include a polarimetric
  calibration unit on board. We report about the development status of
  SUSI and the preliminary results of its calibration.

Title: Unipolar versus Bipolar Internetwork Flux Appearance
Authors: Gosic, Milan; Katsukawa, Yukio; Bellot Rubio, L. R.; Del
   Toro Iniesta, Jose Carlos; Cheung, Mark; Orozco Suárez, David
Bibcode: 2022cosp...44.2513G
Altcode:
  Small-scale internetwork (IN) magnetic fields are considered to be
  the main building blocks of the quiet Sun magnetism. It is therefore
  of paramount importance to understand how these fields are generated
  on the solar surface. To shed new light on this open question,
  we studied the appearance modes and spatio-temporal evolution of
  individual IN magnetic elements inside one supergranular cell. For
  that purpose, we employed a high-resolution, high-sensitivity,
  long-duration Hinode/NFI magnetogram sequence. From identification
  of flux patches and magnetofrictional simulations, we show that there
  are two distinct populations of IN flux concentrations: unipolar and
  bipolar features. Bipolar features tend to be bigger, live longer
  and carry more flux than unipolar features. About $70$% of the total
  instantaneous IN flux detected inside the supergranule is in the form
  of bipoles. Both types of flux concentrations are uniformly distributed
  over the solar surface. However, bipolar features appear (randomly
  oriented) at a faster rate than unipolar features (68 as opposed to
  55~Mx~cm$^{-2}$~day$^{-1}$). Our results lend support to the idea that
  bipolar features may be the signature of local dynamo action, while
  unipolar features seem to be formed by coalescence of background flux.

Title: CASPER: A mission to study the time-dependent evolution of
    the magnetic solar chromosphere and transition regions
Authors: Orozco Suárez, D.; del Toro Iniesta, J. C.; Bailén, F. J.;
   López Jiménez, A.; Balaguez Jiménez, M.; Bellot Rubio, L. R.;
   Ishikawa, R.; Katsukawa, Y.; Kano, R.; Shimizu, T.; Trujillo Bueno,
   J.; Asensio Ramos, A.; del Pino Alemán, T.
Bibcode: 2022ExA...tmp...26O
Altcode:
  Our knowledge about the solar chromosphere and transition region (TR)
  has increased in the last decade thanks to the huge scientific return
  of space-borne observatories like SDO, IRIS, and Hinode, and suborbital
  rocket experiments like CLASP1, CLASP2, and Hi-C. However, the magnetic
  nature of those solar regions remain barely explored. The chromosphere
  and TR of the Sun harbor weak fields and are in a low ionization stage
  both having critical effects on their thermodynamic behavior. Relatively
  cold gas structures, such as spicules and prominences, are located in
  these two regions and display a dynamic evolution in high-resolution
  observations that static and instantaneous 3D-magnetohydrodynamic (MHD)
  models are not able to reproduce. The role of the chromosphere and TR
  as the necessary path to a (largely unexplained) very hot corona calls
  for the generation of observationally based, time-dependent models
  of these two layers that include essential, up to now disregarded,
  ingredients in the modeling such as the vector magnetic field. We
  believe that the community is convinced that the origin of both the
  heat and kinetic energy observed in the upper layers of the solar
  atmosphere is of magnetic origin, but reliable magnetic field
  measurements are missing. The access to sensitive polarimetric
  measurements in the ultraviolet wavelengths has been elusive until
  recently due to limitations in the available technology. We propose a
  low-risk and high-Technology Readiness Level (TRL) mission to explore
  the magnetism and dynamics of the solar chromosphere and TR. The mission
  baseline is a low-Earth, Sun-synchronous orbit at an altitude between
  600 and 800 km. The proposed scientific payload consists of a 30 cm
  aperture telescope with a spectropolarimeter covering the hydrogen
  Ly-alpha and the Mg II h&amp;k ultraviolet lines. The instrument shall
  record high-cadence, full spectropolarimetric observations of the
  solar upper atmosphere. Besides the answers to a fundamental solar
  problem the mission has a broader scientific return. For example,
  the time-dependent modeling of the chromospheres of stars harboring
  exoplanets is fundamental for estimating the planetary radiation
  environment. The mission is based on technologies that are mature
  enough for space and will provide scientific measurements that are
  not available by other means.

Title: The Solar Internetwork. III. Unipolar versus Bipolar Flux
    Appearance
Authors: Gošić, M.; Bellot Rubio, L. R.; Cheung, M. C. M.; Orozco
   Suárez, D.; Katsukawa, Y.; del Toro Iniesta, J. C.
Bibcode: 2022ApJ...925..188G
Altcode: 2021arXiv211103208G
  Small-scale internetwork (IN) magnetic fields are considered to be the
  main building blocks of quiet Sun magnetism. For this reason, it is
  crucial to understand how they appear on the solar surface. Here,
  we employ a high-resolution, high-sensitivity, long-duration
  Hinode/NFI magnetogram sequence to analyze the appearance modes and
  spatiotemporal evolution of individual IN magnetic elements inside a
  supergranular cell at the disk center. From identification of flux
  patches and magnetofrictional simulations, we show that there are
  two distinct populations of IN flux concentrations: unipolar and
  bipolar features. Bipolar features tend to be bigger and stronger
  than unipolar features. They also live longer and carry more flux
  per feature. Both types of flux concentrations appear uniformly over
  the solar surface. However, we argue that bipolar features truly
  represent the emergence of new flux on the solar surface, while
  unipolar features seem to be formed by the coalescence of background
  flux. Magnetic bipoles appear at a faster rate than unipolar features
  (68 as opposed to 55 Mx cm<SUP>-2</SUP> day<SUP>-1</SUP>), and provide
  about 70% of the total instantaneous IN flux detected in the interior
  of the supergranule.

Title: Multi-scale deep learning for estimating horizontal velocity
    fields on the solar surface
Authors: Ishikawa, Ryohtaroh T.; Nakata, Motoki; Katsukawa, Yukio;
   Masada, Youhei; Riethmüller, Tino L.
Bibcode: 2022A&A...658A.142I
Altcode: 2021arXiv211112518I
  Context. The dynamics in the photosphere is governed by the multi-scale
  turbulent convection termed as granulation and supergranulation. It is
  important to derive three-dimensional velocity vectors to understand the
  nature of the turbulent convection and to evaluate the vertical Poynting
  flux toward the upper atmosphere. The line-of-sight component of the
  velocity can be obtained by observing the Doppler shifts. However,
  it is difficult to obtain the velocity component perpendicular to the
  line of sight, which corresponds to the horizontal velocity in disk
  center observations. <BR /> Aims: We present a new method based on a
  deep neural network that can estimate the horizontal velocity from
  the spatial and temporal variations of the intensity and vertical
  velocity. We suggest a new measure for examining the performance of
  the method. <BR /> Methods: We developed a convolutional neural network
  model with a multi-scale deep learning architecture. The method consists
  of multiple convolutional kernels with various sizes of receptive
  fields, and performs convolution for spatial and temporal axes. The
  network is trained with data from three different numerical simulations
  of turbulent convection. Furthermore, we introduced a novel coherence
  spectrum to assess the horizontal velocity fields that were derived for
  each spatial scale. <BR /> Results: The multi-scale deep learning method
  successfully predicts the horizontal velocities for each convection
  simulation in terms of the global correlation coefficient, which is
  often used to evaluate the prediction accuracy of the methods. The
  coherence spectrum reveals the strong dependence of the correlation
  coefficients on the spatial scales. Although the coherence spectra
  are higher than 0.9 for large-scale structures, they drastically
  decrease to less than 0.3 for small-scale structures, wherein the
  global correlation coefficient indicates a high value of approximately
  0.95. By comparing the results of the three convection simulations, we
  determined that this decrease in the coherence spectrum occurs around
  the energy injection scales, which are characterized by the peak of
  the power spectra of the vertical velocities. <BR /> Conclusions: The
  accuracy for the small-scale structures is not guaranteed solely by
  the global correlation coefficient. To improve the accuracy on small
  scales, it is important to improve the loss function for enhancing
  the small-scale structures and to utilize other physical quantities
  related to the nonlinear cascade of convective eddies as input data.

Title: Diagnostic capabilities of spectropolarimetric observations for
    understanding solar phenomena. I. Zeeman-sensitive photospheric lines
Authors: Quintero Noda, C.; Barklem, P. S.; Gafeira, R.; Ruiz Cobo,
   B.; Collados, M.; Carlsson, M.; Martínez Pillet, V.; Orozco Suárez,
   D.; Uitenbroek, H.; Katsukawa, Y.
Bibcode: 2021A&A...652A.161Q
Altcode: 2021arXiv210605084Q
  Future ground-based telescopes will expand our capabilities for
  simultaneous multi-line polarimetric observations in a wide range of
  wavelengths, from the near-ultraviolet to the near-infrared. This
  creates a strong demand to compare candidate spectral lines to
  establish a guideline of the lines that are most appropriate for each
  observation target. We focused in this first work on Zeeman-sensitive
  photospheric lines in the visible and infrared. We first examined their
  polarisation signals and response functions using a 1D semi-empirical
  atmosphere. Then we studied the spatial distribution of the line core
  intensity and linear and circular polarisation signals using a realistic
  3D numerical simulation. We ran inversions of synthetic profiles, and
  we compared the heights at which we obtain a high correlation between
  the input and the inferred atmosphere. We also used this opportunity
  to revisit the atomic information we have on these lines and computed
  the broadening cross-sections due to collisions with neutral hydrogen
  atoms for all the studied spectral lines. The results reveal that
  four spectral lines stand out from the rest for quiet-Sun and network
  conditions: Fe I 5250.2, 6302, 8468, and 15 648 Å. The first three
  form higher in the atmosphere, and the last line is mainly sensitive to
  the atmospheric parameters at the bottom of the photosphere. However,
  as they reach different heights, we strongly recommend using at least
  one of the first three candidates together with the Fe I 15 648 Å line
  to optimise our capabilities for inferring the thermal and magnetic
  properties of the lower atmosphere.

Title: Instrumental design of the Solar Observing Satellite:
    solar-C_EUVST
Authors: Suematsu, Yoshinori; Shimizu, Toshifumi; Hara, Hirohisa;
   Kawate, Tomoko; Katsukawa, Yukio; Ichimoto, Kiyoshi; Imada, Shinsuke
Bibcode: 2021SPIE11852E..3KS
Altcode:
  The EUV High-Throughput Spectroscopic Telescope (EUVST) of Solar-C
  mission is a revolutionary spectrometer that is designed to provide
  high-quality and high cadence spectroscopic data covering a wide
  temperature range of the chromosphere to flaring corona to investigate
  the energetics and dynamics of the solar atmosphere. The EUVST consists
  of only two imaging optical components; a 28-cm clear aperture off-axis
  parabolic primary mirror and a two-split ellipsoidal grating without a
  blocking filter for visible light before the primary mirror to achieve
  unprecedented high spatial and temporal resolution in EUV-UV imaging
  spectroscopic observations. For this reason, about 53 W of sunlight
  is absorbed by the multilayer coating on the mirror. We present an
  instrumental design of the telescope, particularly, primary mirror
  assembly which enables slit-scan observations for imaging spectroscopy,
  an image stabilizing tip-tilt control, and a focus adjustment on
  orbit, together with an optomechanical design of the primary mirror
  and its supporting system which gives optically tolerant wavefront
  error against a large temperature increase due to an absorption of
  visible and IR lights.

Title: Critical Science Plan for the Daniel K. Inouye Solar Telescope
    (DKIST)
Authors: Rast, Mark P.; Bello González, Nazaret; Bellot Rubio,
   Luis; Cao, Wenda; Cauzzi, Gianna; Deluca, Edward; de Pontieu, Bart;
   Fletcher, Lyndsay; Gibson, Sarah E.; Judge, Philip G.; Katsukawa,
   Yukio; Kazachenko, Maria D.; Khomenko, Elena; Landi, Enrico; Martínez
   Pillet, Valentín; Petrie, Gordon J. D.; Qiu, Jiong; Rachmeler,
   Laurel A.; Rempel, Matthias; Schmidt, Wolfgang; Scullion, Eamon; Sun,
   Xudong; Welsch, Brian T.; Andretta, Vincenzo; Antolin, Patrick; Ayres,
   Thomas R.; Balasubramaniam, K. S.; Ballai, Istvan; Berger, Thomas E.;
   Bradshaw, Stephen J.; Campbell, Ryan J.; Carlsson, Mats; Casini,
   Roberto; Centeno, Rebecca; Cranmer, Steven R.; Criscuoli, Serena;
   Deforest, Craig; Deng, Yuanyong; Erdélyi, Robertus; Fedun, Viktor;
   Fischer, Catherine E.; González Manrique, Sergio J.; Hahn, Michael;
   Harra, Louise; Henriques, Vasco M. J.; Hurlburt, Neal E.; Jaeggli,
   Sarah; Jafarzadeh, Shahin; Jain, Rekha; Jefferies, Stuart M.; Keys,
   Peter H.; Kowalski, Adam F.; Kuckein, Christoph; Kuhn, Jeffrey R.;
   Kuridze, David; Liu, Jiajia; Liu, Wei; Longcope, Dana; Mathioudakis,
   Mihalis; McAteer, R. T. James; McIntosh, Scott W.; McKenzie, David
   E.; Miralles, Mari Paz; Morton, Richard J.; Muglach, Karin; Nelson,
   Chris J.; Panesar, Navdeep K.; Parenti, Susanna; Parnell, Clare E.;
   Poduval, Bala; Reardon, Kevin P.; Reep, Jeffrey W.; Schad, Thomas A.;
   Schmit, Donald; Sharma, Rahul; Socas-Navarro, Hector; Srivastava,
   Abhishek K.; Sterling, Alphonse C.; Suematsu, Yoshinori; Tarr, Lucas
   A.; Tiwari, Sanjiv; Tritschler, Alexandra; Verth, Gary; Vourlidas,
   Angelos; Wang, Haimin; Wang, Yi-Ming; NSO and DKIST Project; DKIST
   Instrument Scientists; DKIST Science Working Group; DKIST Critical
   Science Plan Community
Bibcode: 2021SoPh..296...70R
Altcode: 2020arXiv200808203R
  The National Science Foundation's Daniel K. Inouye Solar Telescope
  (DKIST) will revolutionize our ability to measure, understand,
  and model the basic physical processes that control the structure
  and dynamics of the Sun and its atmosphere. The first-light DKIST
  images, released publicly on 29 January 2020, only hint at the
  extraordinary capabilities that will accompany full commissioning of
  the five facility instruments. With this Critical Science Plan (CSP)
  we attempt to anticipate some of what those capabilities will enable,
  providing a snapshot of some of the scientific pursuits that the DKIST
  hopes to engage as start-of-operations nears. The work builds on the
  combined contributions of the DKIST Science Working Group (SWG) and
  CSP Community members, who generously shared their experiences, plans,
  knowledge, and dreams. Discussion is primarily focused on those issues
  to which DKIST will uniquely contribute.

Title: A HAWAII-2RG infrared camera operated under fast readout mode
    for solar polarimetry
Authors: Hanaoka, Yoichiro; Katsukawa, Yukio; Morita, Satoshi; Kamata,
   Yukiko; Ishizuka, Noriyoshi
Bibcode: 2020EP&S...72..181H
Altcode:
  Polarimetry is a crucial method to investigate solar magnetic
  fields. From the viewpoint of space weather, the magnetic field
  in solar filaments, which occasionally erupt and develop into
  interplanetary flux ropes, is of particular interest. To measure
  the magnetic field in filaments, high-performance polarimetry in
  the near-infrared wavelengths employing a high-speed, large-format
  detector is required; however, so far, this has been difficult to be
  realized. Thus, the development of a new infrared camera for advanced
  solar polarimetry has been started, employing a HAWAII-2RG (H2RG)
  array by Teledyne, which has 2048 ×2048 pixels, focusing on the
  wavelengths in the range of 1.0 -1.6 μ m . We solved the problem
  of the difficult operation of the H2RGs under "fast readout mode"
  synchronizing with high-speed polarization modulation by introducing a
  "MACIE" (Markury ASIC Control and Interface Electronics) interface card
  and new assembly codes provided by Markury Scientific. This enables
  polarization measurements with high frame-rates, such as 29-117 frames
  per seconds, using a H2RG. We conducted experimental observations of
  the Sun and confirmed the high polarimetric performance of the camera.

Title: SUNRISE Chromospheric Infrared spectroPolarimeter (SCIP)
for SUNRISE III: Scan mirror mechanism
Authors: Oba, Takayoshi; Shimizu, Toshifumi; Katsukawa, Yukio; Kubo,
   Masahito; Uraguchi, Fumihiro; Tsuzuki, Toshihiro; Tamura, Tomonori;
   Shinoda, Kazuya; Kodeki, Kazuhide; Fukushima, Kazuhiko; Gandorfer,
   Achim; del Toro Iniesta, Jose Carlos
Bibcode: 2020SPIE11445E..4FO
Altcode:
  The SUNRISE Chromospheric Infrared spectroPolarimeter (SCIP) is a
  balloon-borne long-slit spectrograph for SUNRISE III to precisely
  measure magnetic fields in the solar atmosphere. The scan mirror
  mechanism (SMM) is installed in the optical path to the entrance slit
  of the SCIP to move solar images focused on the slit for 2-dimensional
  mapping. The SMM is required to have (1) the tilt stability better
  than 0.035″ (3σ) on the sky angle for the diffraction-limited
  spatial resolution of 0.2″, (2) step response shorter than 32 msec
  for rapid scanning observations, and (3) good linearity (i.e. step
  uniformity) over the entire field-of-view (60″x60″). To achieve
  these performances, we have developed a flight-model mechanism
  and its electronics, in which the mirror tilt is controlled by
  electromagnetic actuators with a closed-loop feedback logic with
  tilt angles from gap-based capacitance sensors. Several optical
  measurements on the optical bench verified that the mechanism meets
  the requirements. In particular, the tilt stability achives better
  than 0.012″ (3σ). Thermal cycling and thermal vacuum tests have
  been completed to demonstrate the performance in the vacuum and the
  operational temperature range expected in the balloon flight. We
  found a small temperature dependence in the step uniformity and this
  dependence will be corrected to have 2-demensional maps with the
  sub-arcsec spatial accuracy in the data post-processing.

Title: Sunrise Chromospheric Infrared spectroPolarimeter (SCIP)
for SUNRISE III: optical design and performance
Authors: Tsuzuki, Toshihiro; Katsukawa, Yukio; Uraguchi, Fumihiro;
   Hara, Hirohisa; Kubo, Masahito; Nodomi, Yoshifumi; Suematsu, Yoshinori;
   Kawabata, Yusuke; Shimizu, Toshifumi; Gandorfer, Achim; Feller, Alex;
   Grauf, Bianca; Solanki, Sami; Carlos del Toro Iniesta, Jose
Bibcode: 2020SPIE11447E..AJT
Altcode:
  The Sunrise Chromospheric Infrared spectroPolarimeter (SCIP) is a
  near-IR spectro-polarimeter instrument newly designed for Sunrise III,
  which is a balloon-borne solar observatory equipped with a 1 m optical
  telescope. To acquire high-quality 3D magnetic and velocity fields,
  SCIP selects the two wavelength bands centered at 850 nm and 770 nm,
  which contain many spectrum lines that are highly sensitive to magnetic
  fields permeating the photosphere and chromosphere. To achieve high
  spatial and spectral resolution (0.21 arcsec and 2 × 10<SUP>5</SUP>),
  SCIP optics adopt a quasi-Littrow configuration based on an echelle
  grating and two high-order aspheric mirrors. Using different diffraction
  orders of the echelle grating, dichroic beam splitter, and polarizing
  beam-splitters, SCIP can obtain s- and p-polarization signals in the
  two wavelength bands simultaneously within a relatively small space. We
  established the wavefront error budget based on tolerance analysis,
  surface figure errors, alignment errors, and environmental changes. In
  addition, we performed stray light analysis, and designed light traps
  and baffles needed to suppress unwanted reflections and diffraction
  by the grating. In this paper, we present the details of this optical
  system and its performance.

Title: Sunrise Chromospheric Infrared spectroPolarimeter (SCIP)
for SUNRISE III: polarization modulation unit
Authors: Kubo, Masahito; Shimizu, Toshifumi; Katsukawa, Yukio;
   Kawabata, Yusuke; Anan, Tetsu; Ichimoto, Kiyoshi; Shinoda, Kazuya;
   Tamura, Tomonori; Nodomi, Yoshifumi; Nakayama, Satoshi; Yamada, Takuya;
   Tajima, Takao; Nakata, Shimpei; Nakajima, Yoshihito; Okutani, Kousei;
   Feller, Alex; del Toro Iniesta, Jose Carlos
Bibcode: 2020SPIE11447E..A3K
Altcode:
  Polarization measurements of the solar chromospheric lines at
  high precision are key to present and future solar telescopes for
  understanding magnetic field structures in the chromosphere. The
  Sunrise Chromospheric Infrared spectroPolarimeter (SCIP) for Sunrise
  III is a spectropolarimeter with a polarimetric precision of 0.03 %
  (1 σ). The key to high-precision polarization measurements using
  SCIP is a polarization modulation unit that rotates a waveplate
  continuously at a constant speed. The rotating mechanism is a DC
  brushless motor originally developed for a future space mission, and
  its control logic was originally developed for the sounding rocket
  experiment CLASP. Because of our requirement on a speed of rotation
  (0.512 s/rotation) that was 10 times faster than that of CLASP, we
  optimized the control logic for the required faster rotation. Fast
  polarization modulation is essential for investigating the fine-scale
  magnetic field structures related to the dynamical chromospheric
  phenomena. We have verified that the rotation performance can achieve
  the polarization precision of 0.03 % (1 σ) required by SCIP and such
  a significant rotation performance is maintained under thermal vacuum
  conditions by simulating the environment of the Sunrise III balloon
  flight. The waveplate was designed as a pair of two birefringent
  plates made of quartz and sapphire to achieve a constant retardation
  in a wide wavelength range. We have confirmed that the retardation
  is almost constant in the 770 nm and 850nm wavelength bands of SCIP
  under the operational temperature conditions.

Title: Sunrise Chromospheric Infrared spectroPolarimeter (SCIP)
for SUNRISE III: opto-mechanical analysis and design
Authors: Uraguchi, Fumihiro; Tsuzuki, Toshihiro; Katsukawa, Yukio;
   Hara, Hirohisa; Iwamura, Satoru; Kubo, Masahito; Nodomi, Yoshifumi;
   Suematsu, Yoshinori; Kawabata, Yusuke; Shimizu, Toshifumi; Gandorfer,
   Achim; del Toro Iniesta, Jose Carlos
Bibcode: 2020SPIE11447E..ABU
Altcode:
  The Sunrise Chromospheric Infrared spectroPolarimeter (SCIP) is a
  near-IR spectro-polarimeter instrument newly designed for Sunrise III,
  a balloon-borne solar observatory with a 1-m diameter telescope. In
  order to achieve the strict requirements the SCIP wavefront error, it is
  necessary to quantify the errors due to environmen- tal effects such as
  gravity and temperature variation under the observation conditions. We
  therefore conducted an integrated opto-mechanical analysis incorporating
  mechanical and thermal disturbances into a finite element model of
  the entire SCIP structure to acquire the nodal displacements of each
  optical element, then fed them back to the optical analysis software
  in the form of rigid body motion and surface deformation fitted by
  polynomials. This method allowed us to determine the error factors
  having a significant influence on optical performance. For example,
  no significant wavefront degradation was associated with the structural
  mountings because the optical element mounts were well designed based
  on quasi-kinematic constraints. In contrast, we found that the main
  factor affecting wavefront degradation was the rigid body motions of
  the optical elements, which must be mini- mized within the allowable
  level. Based on these results, we constructed the optical bench using a
  sandwich panel as the optical bench consisting of an aluminum-honeycomb
  core and carbon fiber reinforced plastic skins with a high stiffness
  and low coefficient of thermal expansion. We then confirmed that the
  new opto-mechanical model achieved the wavefront error requirement. In
  this paper, we report the details of this integrated opto-mechanical
  analysis, including the wavefront error budgeting and the design of
  the opto-mechanics.

Title: The SUNRISE UV Spectropolarimeter and imager for SUNRISE III
Authors: Feller, Alex; Gandorfer, Achim; Iglesias, Francisco A.;
   Lagg, Andreas; Riethmüller, Tino L.; Solanki, Sami K.; Katsukawa,
   Yukio; Kubo, Masahito
Bibcode: 2020SPIE11447E..AKF
Altcode:
  Sunrise is a balloon-borne solar observatory dedicated to the
  investigation of key processes of the magnetic field and the plasma
  flows in the lower solar atmosphere. The observatory operates in
  the stratosphere at an altitude of around 37 km in order to avoid
  image degradation due to turbulence in the Earth's atmosphere and to
  access the UV range. The third science flight of Sunrise will carry new
  instrumentation which samples the solar spectrum over a broad wavelength
  domain from the UV to the near IR and covers an extended height range in
  the solar atmosphere. A key feature of the Sunrise UV Spectropolarimeter
  and Imager (SUSI) operating between 309 nm and 417 nm, is its capability
  to simultaneously record a large number of spectral lines. By combining
  the spectral and polarization information of many individual lines
  with different formation heights and sensitivities, the accuracy and
  the height resolution of the inferred atmospheric parameters can be
  significantly increased. The spectral bands of SUSI are selected one
  at a time by rotating a diffraction grating with respect to a fixed
  polarimetry unit. The spatial and spectral field of view on the 2k x
  2k cameras is 59" and 2.0 - 2.3 nm, respectively. A further innovation
  is the numerical restoration of the spectrograph scans by means of
  synchronized 2D context imaging, a technique that has recently produced
  impressive results at ground-based solar observatories.

Title: The Solar-C (EUVST) mission: the latest status
Authors: Shimizu, Toshifumi; Imada, Shinsuke; Kawate, Tomoko; Suematsu,
   Yoshinori; Hara, Hirohisa; Tsuzuki, Toshihiro; Katsukawa, Yukio; Kubo,
   Masahito; Ishikawa, Ryoko; Watanabe, Tetsuya; Toriumi, Shin; Ichimoto,
   Kiyoshi; Nagata, Shin'ichi; Hasegawa, Takahiro; Yokoyama, Takaaki;
   Watanabe, Kyoko; Tsuno, Katsuhiko; Korendyke, Clarence M.; Warren,
   Harry; De Pontieu, Bart; Boerner, Paul; Solanki, Sami K.; Teriaca,
   Luca; Schuehle, Udo; Matthews, Sarah; Long, David; Thomas, William;
   Hancock, Barry; Reid, Hamish; Fludra, Andrzej; Auchère, Frederic;
   Andretta, Vincenzo; Naletto, Giampiero; Poletto, Luca; Harra, Louise
Bibcode: 2020SPIE11444E..0NS
Altcode:
  Solar-C (EUVST) is the next Japanese solar physics mission to
  be developed with significant contributions from US and European
  countries. The mission carries an EUV imaging spectrometer with
  slit-jaw imaging system called EUVST (EUV High-Throughput Spectroscopic
  Telescope) as the mission payload, to take a fundamental step towards
  answering how the plasma universe is created and evolves and how the
  Sun influences the Earth and other planets in our solar system. In
  April 2020, ISAS (Institute of Space and Astronautical Science) of JAXA
  (Japan Aerospace Exploration Agency) has made the final down-selection
  for this mission as the 4th in the series of competitively chosen
  M-class mission to be launched with an Epsilon launch vehicle in mid
  2020s. NASA (National Aeronautics and Space Administration) has selected
  this mission concept for Phase A concept study in September 2019 and
  is in the process leading to final selection. For European countries,
  the team has (or is in the process of confirming) confirmed endorsement
  for hardware contributions to the EUVST from the national agencies. A
  recent update to the mission instrumentation is to add a UV spectral
  irradiance monitor capability for EUVST calibration and scientific
  purpose. This presentation provides the latest status of the mission
  with an overall description of the mission concept emphasizing on key
  roles of the mission in heliophysics research from mid 2020s.

Title: Sunrise Chromospheric Infrared SpectroPolarimeter (SCIP)
for sunrise III: system design and capability
Authors: Katsukawa, Y.; del Toro Iniesta, J. C.; Solanki, S. K.;
   Kubo, M.; Hara, H.; Shimizu, T.; Oba, T.; Kawabata, Y.; Tsuzuki,
   T.; Uraguchi, F.; Nodomi, Y.; Shinoda, K.; Tamura, T.; Suematsu,
   Y.; Ishikawa, R.; Kano, R.; Matsumoto, T.; Ichimoto, K.; Nagata, S.;
   Quintero Noda, C.; Anan, T.; Orozco Suárez, D.; Balaguer Jiménez,
   M.; López Jiménez, A. C.; Cobos Carrascosa, J. P.; Feller, A.;
   Riethmueller, T.; Gandorfer, A.; Lagg, A.
Bibcode: 2020SPIE11447E..0YK
Altcode:
  The Sunrise balloon-borne solar observatory carries a 1 m aperture
  optical telescope and provides us a unique platform to conduct
  continuous seeing-free observations at UV-visible-IR wavelengths from
  an altitude of higher than 35 km. For the next flight planned for
  2022, the post-focus instrumentation is upgraded with new spectro-
  polarimeters for the near UV (SUSI) and the near-IR (SCIP), whereas
  the imaging spectro-polarimeter Tunable Magnetograph (TuMag) is capable
  of observing multiple spectral lines within the visible wavelength. A
  new spectro-polarimeter called the Sunrise Chromospheric Infrared
  spectroPolarimeter (SCIP) is under development for observing near-IR
  wavelength ranges of around 770 nm and 850 nm. These wavelength ranges
  contain many spectral lines sensitive to solar magnetic fields and
  SCIP will be able to obtain magnetic and velocity structures in the
  solar atmosphere with a sufficient height resolution by combining
  spectro-polarimetric data of these lines. Polarimetric measurements are
  conducted using a rotating waveplate as a modulator and polarizing beam
  splitters in front of the cameras. The spatial and spectral resolutions
  are 0.2" and 2 105, respectively, and a polarimetric sensitivity of
  0.03 % (1σ) is achieved within a 10 s integration time. To detect
  minute polarization signals with good precision, we carefully designed
  the opto-mechanical system, polarization optics and modulation, and
  onboard data processing.

Title: Current Status of the Solar-C_EUVST Mission
Authors: Imada, S.; Shimizu, T.; Kawate, T.; Toriumi, S.; Katsukawa,
   Y.; Kubo, M.; Hara, H.; Suematsu, Y.; Ichimoto, K.; Watanabe, T.;
   Watanabe, K.; Yokoyama, T.; Warren, H.; Long, D.; Harra, L. K.;
   Teriaca, L.
Bibcode: 2020AGUFMSH056..05I
Altcode:
  Solar-C_EUVST (EUV High-Throughput Spectroscopic Telescope) is designed
  to comprehensively understand the energy and mass transfer from the
  solar surface to the solar corona and interplanetary space, and to
  investigate the elementary processes that take place universally
  in cosmic plasmas. As a fundamental step towards answering how the
  plasma universe is created and evolves, and how the Sun influences
  the Earth and other planets in our solar system, the proposed mission
  is designed to comprehensively understand how mass and energy are
  transferred throughout the solar atmosphere. Understanding the solar
  atmosphere, which connects to the heliosphere via radiation, the solar
  wind and coronal mass ejections, and energetic particles is pivotal
  for establishing the conditions for life and habitability in the solar
  system. <P />The two primary science objectives for Solar-C_EUVST are :
  I) Understand how fundamental processes lead to the formation of the
  solar atmosphere and the solar wind, II) Understand how the solar
  atmosphere becomes unstable, releasing the energy that drives solar
  flares and eruptions. Solar-C_EUVST will, A) seamlessly observe all
  the temperature regimes of the solar atmosphere from the chromosphere
  to the corona at the same time, B) resolve elemental structures of the
  solar atmosphere with high spatial resolution and cadence to track their
  evolution, and C) obtain spectroscopic information on the dynamics of
  elementary processes taking place in the solar atmosphere. <P />In this
  talk, we will first discuss the science target of the Solar-C_EUVST,
  and then discuss the current status of the Solar-C_EUVST mission.

Title: Thermal design of the Solar-C (EUVST) telescope
Authors: Suematsu, Yoshinori; Shimizu, Toshifumi; Hara, Hirohisa;
   Kawate, Tomoko; Katsukawa, Yukio; Ichimoto, Kiyoshi; Imada, Shinsuke;
   Nagae, Kazuhiro; Yamazaki, Atsumu; Hattori, Tomoya
Bibcode: 2020SPIE11444E..3KS
Altcode:
  The EUV High-Throughput Spectroscopic Telescope (EUVST) of Solar-C
  mission consists of only two imaging optical components; a 28-cm clear
  aperture off-axis parabolic primary mirror and a two-split ellipsoidal
  grating without a blocking filter for visible light before the primary
  mirror to achieve unprecedented high spatial and temporal resolution in
  EUV-UV imaging spectroscopic observations. For this reason, about 60
  W of sunlight is absorbed by the multilayer coating on the mirror. We
  report a thermal design of telescope in which the temperature of the
  primary mirror bonding part and underlying tip-tilt and slit-scanning
  mechanisms is well lower than a glass transition temperature of adhesive
  (about 60°C) and thermal deformation of the primary mirror is small,
  although it is non-negligibly small.

Title: A sensitivity analysis of the updated optical design for
    EUVST on the Solar-C mission
Authors: Kawate, Tomoko; Tsuzuki, Toshihiro; Shimizu, Toshifumi;
   Imada, Shinsuke; Katsukawa, Yukio; Hara, Hirohisa; Suematsu, Yoshinori;
   Ichimoto, Kiyoshi; Hattori, Tomoya; Narasaki, Shota; Warren, Harry P.;
   Teriaca, Luca; Korendyke, Clarence M.; Brown, Charles M.; Auchere,
   Frederic
Bibcode: 2020SPIE11444E..3JK
Altcode:
  The EUV high-throughput spectroscopic telescope (EUVST) onboard the
  Solar-C mission has the high spatial (0.4'') resolution over a wide
  wavelength range in the vacuum ultraviolet. To achieve high spatial
  resolution under a design constraint given by the JAXA Epsilon launch
  vehicle, we further update the optical design to secure margins
  needed to realize 0.4'' spatial resolution over a field of view of
  100''×100''. To estimate the error budgets of spatial and spectral
  resolutions due to installation and fabrication errors, we perform a
  sensitivity analysis for the position and orientation of each optical
  element and for the grating parameters by ray tracing with the Zemax
  software. We obtain point spread functions (PSF) for rays from 9
  fields and at 9 wavelengths on each detector by changing each parameter
  slightly. A full width at half maximum (FWHM) of the PSF is derived at
  each field and wavelength position as a function of the perturbation
  of each optical parameter. Assuming a mount system of each optical
  element and an error of each optical parameter, we estimate spatial
  and spectral resolutions by taking installation and fabrication errors
  into account. The results of the sensitivity analysis suggest that
  budgets of the total of optical design and the assembly errors account
  for 15% and 5.8% of our budgets of the spatial resolution in the long
  wavelength and short wavelength bands, respectively. On the other hand,
  the grating fabrication errors give a large degradation of spatial and
  spectral resolutions, and investigations of compensators are needed
  to relax the fabrication tolerance of the grating surface parameters.

Title: Temporal and Spatial Scales in Coronal Rain Revealed by UV
    Imaging and Spectroscopic Observations
Authors: Ishikawa, Ryohtaroh T.; Katsukawa, Yukio; Antolin, Patrick;
   Toriumi, Shin
Bibcode: 2020SoPh..295...53I
Altcode: 2020arXiv200313214I
  Coronal rain corresponds to cool and dense clumps in the corona
  accreting towards the solar surface; it is often observed above solar
  active regions. These clumps are generally thought to be produced by
  a thermal instability in the corona and their lifetime is limited by
  the time they take to reach the chromosphere. Although the rain usually
  fragments into smaller clumps while falling down, their specific spatial
  and temporal scales remain unclear. In addition, the observational
  signatures of the impact of the rain with the chromosphere have not been
  clarified yet. In this study, we investigate the time evolution of the
  velocity and intensity of coronal rain above a sunspot by analyzing
  coronal images obtained by the Atmospheric Imaging Assembly (AIA)
  onboard the Solar Dynamics Observatory (SDO) as well as the slit-jaw
  images (SJIs) and spectral data taken by the Interface Region Imaging
  Spectrograph (IRIS) satellite. We identify dark and bright threads
  moving towards the umbra in AIA images and in SJIs, respectively,
  and co-spatial chromospheric intensity enhancements and redshifts in
  three IRIS spectral lines, Mg II k 2796 Å, Si IV 1394 Å, and C II
  1336 Å. The intensity enhancements and coronal rain redshifts occur
  almost concurrently in all the three lines, which clearly demonstrates
  the causal relationship with coronal rain. Furthermore, we detect bursty
  intensity variation with a time scale shorter than 1 minute in Mg II k,
  Si IV, and C II, indicating that a length scale of rain clumps is about
  2.7 Mm if we multiply the typical time scale of the busty intensity
  variation at 30 sec by the rain velocity at 90 kms−<SUP>1</SUP>. Such
  rapid enhancements in the IRIS lines are excited within a time lag
  of 5.6 sec limited by the temporal resolution. These temporal and
  spatial scales may reflect the physical processes responsible for
  the rain morphology, and are suggestive of instabilities such as the
  Kelvin-Helmholtz instability.

Title: Study of the Dynamics of Convective Turbulence in the Solar
    Granulation by Spectral Line Broadening and Asymmetry
Authors: Ishikawa, Ryohtaroh T.; Katsukawa, Yukio; Oba, Takayoshi;
   Nakata, Motoki; Nagaoka, Kenichi; Kobayashi, Tatsuya
Bibcode: 2020ApJ...890..138I
Altcode: 2020arXiv200104632I
  In quiet regions on the solar surface, turbulent convective motions
  of granulation play an important role in creating small-scale
  magnetic structures, as well as in energy injection into the upper
  atmosphere. The turbulent nature of granulation can be studied using
  spectral line profiles, especially line broadening, which contain
  information on the flow field smaller than the spatial resolution of
  an instrument. Moreover, the Doppler velocity gradient along a line of
  sight (LOS) causes line broadening as well. However, the quantitative
  relationship between velocity gradient and line broadening has not
  been understood well. In this study, we perform bisector analyses
  using the spectral profiles obtained using the spectropolarimeter of
  the Hinode/Solar Optical Telescope to investigate the relationship of
  line broadening and bisector velocities with the granulation flows. The
  results indicate that line broadening has a positive correlation with
  the Doppler velocity gradients along the LOS. We found excessive line
  broadening in fading granules, that cannot be explained only by the
  LOS velocity gradient, although the velocity gradient is enhanced in
  the process of fading. If this excessive line broadening is attributed
  to small-scale turbulent motions, the averaged turbulent velocity is
  obtained as 0.9 km s<SUP>-1</SUP>.

Title: Dynamics of the Convective Turbulence in the Solar Granulation
    Studied by the Spectral Line Broadening and Asymmetry
Authors: Ishikawa, R.; Katsukawa, Y.; Oba, T.; Nakata, M.; Nagaoka,
   K.; Kobayashi, T.
Bibcode: 2019AGUFMSH43E3385I
Altcode:
  In the quiet region on the solar surface, turbulent convective motions
  of the granulation play an important role for creating small-scale
  magnetic structures as well as the energy injection into the upper
  atmosphere. The turbulent nature can be studied using spectral line
  profiles, especially line broadening, that contains information on the
  flow field smaller than the spatial resolution of an instrument. Doppler
  velocity gradient along a line-of-sight (LOS) is also a source of
  line broadening. However, the quantitative relation between velocity
  gradient and line broadening is not well understood. In this study,
  we perform bisector analyses using spectral profiles obtained with the
  Spectro-Polarimeter of Hinode Solar Optical Telescope to investigate
  how the line broadening and the bisector velocities are related with
  granulation flows. Our result indicates that the line broadening has a
  positive correlation with the LOS gradient of Doppler velocities. We
  found excessive line broadening in fading granules that cannot be
  explained only by the LOS velocity gradient, although the velocity
  gradient is enhanced in the course of fading granules. If we attribute
  the excessive line broadening to small-scale turbulent motions, the
  averaged turbulent velocity is 1.6 km/s.

Title: Development of Solar-C_EUVST structural design
Authors: Suematsu, Yoshinori; Shimizu, Toshifumi; Hara, Hirohisa;
   Katsukawa, Yukio; Kawate, Tomoko; Ichimoto, Kiyoshi; Imada, Shinsuke
Bibcode: 2019SPIE11118E..1OS
Altcode:
  The Solar-C_EUVST is a mission designed to provide high-quality solar
  spectroscopic data covering a wide temperature range of the chromosphere
  to flaring corona. To fulfill a high throughput requirement, the
  instrument consists of only two optical components; a 28-cm primary
  mirror and a segmented toroidal grating which have high reflective
  coatings in EUV-UV range. We present a mission payload structural
  design which accommodates long focal length optical components and
  a launcher condition/launch environment (JAXA Epsilon). We also
  present a mechanical design of primary mirror assembly which enables
  slit-scan observations, an image stabilizing tip-tilt control, and a
  focus adjustment on orbit, together with an optomechanical design of
  the primary mirror and its supporting system which gives optically
  tolerant wavefront error against a large temperature increase due to
  an absorption of visible and IR lights.

Title: Concept study of Solar-C_EUVST optical design
Authors: Kawate, Tomoko; Shimizu, Toshifumi; Imada, Shinsuke; Tsuzuki,
   Toshihiro; Katsukawa, Yukio; Hara, Hirohisa; Suematsu, Yoshinori;
   Ichimoto, Kiyoshi; Warren, Harry; Teriaca, Luca; Korendyke, Clarence
   M.; Brown, Charles
Bibcode: 2019SPIE11118E..1NK
Altcode:
  The main characteristics of Solar-C_EUVST are the high temporal and
  high spatial resolutions over a wide temperature coverage. In order
  to realize the instrument for meeting these scientific requirements
  under size constraints given by the JAXA Epsilon vehicle, we examined
  four-dimensional optical parameter space of possible solutions of
  geometrical optical parameters such as mirror diameter, focal length,
  grating magnification, and so on. As a result, we have identified
  the solution space that meets the EUVST science objectives and rocket
  envelope requirements. A single solution was selected and used to define
  the initial optical parameters for the concept study of the baseline
  architecture for defining the mission concept. For this solution, we
  optimized the grating and geometrical parameters by ray tracing of the
  Zemax software. Consequently, we found an optics system that fulfills
  the requirement for a 0.4" angular resolution over a field of view of
  100" (including margins) covering spectral ranges of 170-215, 463-542,
  557-637, 690-850, 925-1085, and 1115-1275 A. This design achieves an
  effective area 10 times larger than the Extreme-ultraviolet Imaging
  Spectrometer onboard the Hinode satellite, and will provide seamless
  observations of 4.2-7.2 log(K) plasmas for the first time. Tolerance
  analyses were performed based on the optical design, and the moving
  range and step resolution of focus mechanisms were identified. In
  the presentation, we describe the derivation of the solution space,
  optimization of the optical parameters, and show the results of ray
  tracing and tolerance analyses.

Title: The Solar-C_EUVST mission
Authors: Shimizu, Toshifumi; Imada, Shinsuke; Kawate, Tomoko;
   Ichimoto, Kiyoshi; Suematsu, Yoshinori; Hara, Hirohisa; Katsukawa,
   Yukio; Kubo, Masahito; Toriumi, Shin; Watanabe, Tetsuya; Yokoyama,
   Takaaki; Korendyke, Clarence M.; Warren, Harry P.; Tarbell, Ted; De
   Pontieu, Bart; Teriaca, Luca; Schühle, Udo H.; Solanki, Sami; Harra,
   Louise K.; Matthews, Sarah; Fludra, A.; Auchère, F.; Andretta, V.;
   Naletto, G.; Zhukov, A.
Bibcode: 2019SPIE11118E..07S
Altcode:
  Solar-C EUVST (EUV High-Throughput Spectroscopic Telescope) is a
  solar physics mission concept that was selected as a candidate for
  JAXA competitive M-class missions in July 2018. The onboard science
  instrument, EUVST, is an EUV spectrometer with slit-jaw imaging
  system that will simultaneously observe the solar atmosphere from the
  photosphere/chromosphere up to the corona with seamless temperature
  coverage, high spatial resolution, and high throughput for the first
  time. The mission is designed to provide a conclusive answer to the
  most fundamental questions in solar physics: how fundamental processes
  lead to the formation of the solar atmosphere and the solar wind, and
  how the solar atmosphere becomes unstable, releasing the energy that
  drives solar flares and eruptions. The entire instrument structure
  and the primary mirror assembly with scanning and tip-tilt fine
  pointing capability for the EUVST are being developed in Japan, with
  spectrograph and slit-jaw imaging hardware and science contributions
  from US and European countries. The mission will be launched and
  installed in a sun-synchronous polar orbit by a JAXA Epsilon vehicle in
  2025. ISAS/JAXA coordinates the conceptual study activities during the
  current mission definition phase in collaboration with NAOJ and other
  universities. The team is currently working towards the JAXA final
  down-selection expected at the end of 2019, with strong support from
  US and European colleagues. The paper provides an overall description
  of the mission concept, key technologies, and the latest status.

Title: Development of an Infrared Camera Using a Hawaii-2RG Detector
    for Solar Polarimetry.
Authors: Hanaoka, Y.; Katsukawa, Y.; Morita, S.; Kamata, Y.;
   Ishizuka, N.
Bibcode: 2019spw..confE...9H
Altcode:
  No abstract at ADS

Title: Design of all-reflective space-borne 1-m aperture solar
    optical telescope
Authors: Suematsu, Y.; Hara, H.; Katsukawa, Y.; Kano, R.; Shimizu,
   T.; Ichimoto, K.
Bibcode: 2019SPIE11180E..0RS
Altcode:
  A 1-m aperture optical telescope is planned for a future Japanese solar
  mission. The telescope is designed to provide high spatial resolution
  data of solar lower atmosphere from the photosphere to the uppermost
  chromosphere with enhanced spectroscopic and spectro-polarimetric
  capabilities covering a wide wavelength region from UV to near IR where
  many useful spectral lines and continua exist for physical diagnosis of
  the solar magnetized atmosphere. We designed an allreflective telescope
  to fulfill the scientific and engineering requirements. From a thermal
  view point, a Gregorian telescope is the most suitable. To avoid
  chromatic aberration, a tri-aspheric-mirror collimator coupling to
  the Gregorian was designed to give a diffraction-limited performance
  over the FOV by allowing a field curvature. The field curvature can
  be compensated by an off-axis Ritchey Chretien reimaging optics at an
  entrance of focal plane instrument, which has an opposite sign in the
  field curvature to the Gregorian. We also briefly studied structural
  design of all-reflective 1-m aperture solar optical telescope for the
  space solar mission.

Title: Chromospheric polarimetry through multiline observations of
the 850 nm spectral region III: Chromospheric jets driven by twisted
    magnetic fields
Authors: Quintero Noda, C.; Iijima, H.; Katsukawa, Y.; Shimizu,
   T.; Carlsson, M.; de la Cruz Rodríguez, J.; Ruiz Cobo, B.; Orozco
   Suárez, D.; Oba, T.; Anan, T.; Kubo, M.; Kawabata, Y.; Ichimoto,
   K.; Suematsu, Y.
Bibcode: 2019MNRAS.486.4203Q
Altcode: 2019MNRAS.tmp.1081N; 2019arXiv190409151Q
  We investigate the diagnostic potential of the spectral lines at 850
  nm for understanding the magnetism of the lower atmosphere. For that
  purpose, we use a newly developed 3D simulation of a chromospheric
  jet to check the sensitivity of the spectral lines to this phenomenon
  as well as our ability to infer the atmospheric information through
  spectropolarimetric inversions of noisy synthetic data. We start
  comparing the benefits of inverting the entire spectrum at 850 nm versus
  only the Ca II 8542 Å spectral line. We found a better match of the
  input atmosphere for the former case, mainly at lower heights. However,
  the results at higher layers were not accurate. After several tests,
  we determined that we need to weight more the chromospheric lines
  than the photospheric ones in the computation of the goodness of the
  fit. The new inversion configuration allows us to obtain better fits and
  consequently more accurate physical parameters. Therefore, to extract
  the most from multiline inversions, a proper set of weights needs to
  be estimated. Besides that, we conclude again that the lines at 850
  nm, or a similar arrangement with Ca II 8542 Å plus Zeeman-sensitive
  photospheric lines, pose the best-observing configuration for examining
  the thermal and magnetic properties of the lower solar atmosphere.

Title: Comparison of Scattering Polarization Signals Observed by
CLASP: Possible Indication of the Hanle Effect
Authors: Ishikawa, R.; Trujillo Bueno, J.; Uitenbroek, H.; Kubo, M.;
   Tsuneta, S.; Goto, M.; Kano, R.; Narukage, N.; Bando, T.; Katsukawa,
   Y.; Ishikawa, S.; Giono, G.; Suematsu, Y.; Hara, H.; Shimizu, T.;
   Sakao, T.; Winebarger, A.; Kobayashi, K.; Cirtain, J.; Champey, P.;
   Auchère, F.; Štěpán, J.; Belluzzi, L.; Asensio Ramos, A.; Manso
   Sainz, R.; De Pomtieu, B.; Ichimoto, K.; Carlsson, M.; Casini, R.
Bibcode: 2019ASPC..526..305I
Altcode:
  The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP; Kano et
  al. 2012; Kobayashi et al. 2012; Kubo et al. 2014) observed, for the
  first time, the linear polarization produced by scattering processes
  in the hydrogen Lyman-α (121.57 nm) and Si III (120.56 nm) lines of
  the solar disk radiation. The complexity of the observed scattering
  polarization (i.e., conspicuous spatial variations in Q/I and U/I
  at spatial scales of 10″-20″ and the absence of center-to- limb
  variation at the Lyman-α center; see Kano et al. 2017) motivated us
  to search for possible hints of the operation of the Hanle effect by
  comparing: (a) the Lyman-α line center signal, for which the critical
  field strength (B<SUB>H</SUB>) for the onset of the Hanle effect is
  53 G, (b) the Lyman-α wing, which is insensitive to the Hanle effect,
  and (c) the Si III line, whose B<SUB>H</SUB> = 290 G. We focus on four
  regions with different total unsigned photospheric magnetic fluxes
  (estimated from SDO/HMI observations), and compare the corresponding
  U/I spatial variations in the Lyman-α wing, Lyman-α center, and Si III
  line. The U/I signal in the Lyman-α wing shows an antisymmetric spatial
  distribution, which is caused by the presence of a bright structure in
  all the selected regions, regardless of the total unsigned photospheric
  magnetic flux. In an internetwork region, the Lyman-α center shows an
  antisymmetric spatial variation across the selected bright structure,
  but it does not show it in other more magnetized regions. In the Si III
  line, the spatial variation of U/I deviates from the above-mentioned
  antisymmetric shape as the total unsigned photospheric magnetic flux
  increases. We argue that a plausible explanation of this differential
  behavior is the operation of the Hanle effect. <P />This work, presented
  in an oral contribution at this Workshop, has been published on The
  Astrophysical Journal (Ishikawa et al. 2017).

Title: Observations of photospheric magnetic structure below a dark
    filament using the Hinode Spectro-Polarimeter
Authors: Yokoyama, Takaaki; Katsukawa, Yukio; Shimojo, Masumi
Bibcode: 2019PASJ...71...46Y
Altcode: 2019arXiv190110695Y; 2019PASJ..tmp...26Y
  The structure of the photospheric vector magnetic field below a
  dark filament on the Sun is studied using the observations of the
  Spectro-Polarimeter attached to the Solar Optical Telescope onboard
  Hinode. Special attention is paid to discriminating between two
  suggested models, a flux rope or a bent arcade. "Inverse polarity"
  orientation is possible below the filament in a flux rope, whereas
  "normal polarity" can appear in both models. We study a filament in the
  active region NOAA 10930, which appeared on the solar disk during 2006
  December. The transverse field perpendicular to the line of sight has a
  direction almost parallel to the filament spine with a shear angle of
  30°, the orientation of which includes the 180° ambiguity. To know
  whether it is in the normal orientation or in the inverse one, the
  center-to-limb variation is used for the solution under the assumption
  that the filament does not drastically change its magnetic structure
  during the passage. When the filament is near the east limb, we found
  that the line-of-site magnetic component below the filament is positive,
  while it is negative near the west limb.This change of sign indicates
  that the horizontal photospheric field perpendicular to the polarity
  inversion line beneath the filament has an "inverse-polarity", which
  indicates a flux-rope structure of the filament supporting field.

Title: Study of the polarization produced by the Zeeman effect in
    the solar Mg I b lines
Authors: Quintero Noda, C.; Uitenbroek, H.; Carlsson, M.; Orozco
   Suárez, D.; Katsukawa, Y.; Shimizu, T.; Ruiz Cobo, B.; Kubo, M.; Oba,
   T.; Kawabata, Y.; Hasegawa, T.; Ichimoto, K.; Anan, T.; Suematsu, Y.
Bibcode: 2018MNRAS.481.5675Q
Altcode: 2018arXiv181001067Q; 2018MNRAS.tmp.2566Q
  The next generation of solar observatories aim to understand the
  magnetism of the solar chromosphere. Therefore, it is crucial to
  understand the polarimetric signatures of chromospheric spectral
  lines. For this purpose, we here examine the suitability of the three
  Fraunhofer Mg I b<SUB>1</SUB>, b<SUB>2</SUB>, and b<SUB>4</SUB> lines
  at 5183.6, 5172.7, and 5167.3 Å, respectively. We start by describing
  a simplified atomic model of only six levels and three line transitions
  for computing the atomic populations of the 3p-4s (multiplet number
  2) levels involved in the Mg I b line transitions assuming non-local
  thermodynamic conditions and considering only the Zeeman effect using
  the field-free approximation. We test this simplified atom against
  more complex ones finding that, although there are differences in the
  computed profiles, they are small compared with the advantages provided
  by the simple atom in terms of speed and robustness. After comparing
  the three Mg I lines, we conclude that the most capable one is the
  b<SUB>2</SUB> line as b<SUB>1</SUB> forms at similar heights and always
  shows weaker polarization signals, while b<SUB>4</SUB> is severely
  blended with photospheric lines. We also compare Mg I b<SUB>2</SUB>
  with the K I D<SUB>1</SUB> and Ca II 8542 Å lines finding that the
  former is sensitive to the atmospheric parameters at heights that
  are in between those covered by the latter two lines. This makes Mg I
  b<SUB>2</SUB> an excellent candidate for future multiline observations
  that aim to seamlessly infer the thermal and magnetic properties of
  different features in the lower solar atmosphere.

Title: Solar Ultraviolet Bursts
Authors: Young, Peter R.; Tian, Hui; Peter, Hardi; Rutten, Robert J.;
   Nelson, Chris J.; Huang, Zhenghua; Schmieder, Brigitte; Vissers, Gregal
   J. M.; Toriumi, Shin; Rouppe van der Voort, Luc H. M.; Madjarska, Maria
   S.; Danilovic, Sanja; Berlicki, Arkadiusz; Chitta, L. P.; Cheung, Mark
   C. M.; Madsen, Chad; Reardon, Kevin P.; Katsukawa, Yukio; Heinzel, Petr
Bibcode: 2018SSRv..214..120Y
Altcode: 2018arXiv180505850Y
  The term "ultraviolet (UV) burst" is introduced to describe small,
  intense, transient brightenings in ultraviolet images of solar active
  regions. We inventorize their properties and provide a definition
  based on image sequences in transition-region lines. Coronal signatures
  are rare, and most bursts are associated with small-scale, canceling
  opposite-polarity fields in the photosphere that occur in emerging flux
  regions, moving magnetic features in sunspot moats, and sunspot light
  bridges. We also compare UV bursts with similar transition-region
  phenomena found previously in solar ultraviolet spectrometry and
  with similar phenomena at optical wavelengths, in particular Ellerman
  bombs. Akin to the latter, UV bursts are probably small-scale magnetic
  reconnection events occurring in the low atmosphere, at photospheric
  and/or chromospheric heights. Their intense emission in lines with
  optically thin formation gives unique diagnostic opportunities
  for studying the physics of magnetic reconnection in the low solar
  atmosphere. This paper is a review report from an International Space
  Science Institute team that met in 2016-2017.

Title: CLASP Constraints on the Magnetization and Geometrical
    Complexity of the Chromosphere-Corona Transition Region
Authors: Trujillo Bueno, J.; Štěpán, J.; Belluzzi, L.; Asensio
   Ramos, A.; Manso Sainz, R.; del Pino Alemán, T.; Casini, R.; Ishikawa,
   R.; Kano, R.; Winebarger, A.; Auchère, F.; Narukage, N.; Kobayashi,
   K.; Bando, T.; Katsukawa, Y.; Kubo, M.; Ishikawa, S.; Giono, G.; Hara,
   H.; Suematsu, Y.; Shimizu, T.; Sakao, T.; Tsuneta, S.; Ichimoto, K.;
   Cirtain, J.; Champey, P.; De Pontieu, B.; Carlsson, M.
Bibcode: 2018ApJ...866L..15T
Altcode: 2018arXiv180908865T
  The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a
  suborbital rocket experiment that on 2015 September 3 measured
  the linear polarization produced by scattering processes in the
  hydrogen Lyα line of the solar disk radiation. The line-center
  photons of this spectral line radiation mostly stem from the
  chromosphere-corona transition region (TR). These unprecedented
  spectropolarimetric observations revealed an interesting surprise,
  namely that there is practically no center-to-limb variation (CLV) in
  the Q/I line-center signals. Using an analytical model, we first show
  that the geometric complexity of the corrugated surface that delineates
  the TR has a crucial impact on the CLV of the Q/I and U/I line-center
  signals. Second, we introduce a statistical description of the solar
  atmosphere based on a 3D model derived from a state-of-the-art radiation
  magnetohydrodynamic simulation. Each realization of the statistical
  ensemble is a 3D model characterized by a given degree of magnetization
  and corrugation of the TR, and for each such realization we solve the
  full 3D radiative transfer problem taking into account the impact
  of the CLASP instrument degradation on the calculated polarization
  signals. Finally, we apply the statistical inference method presented
  in a previous paper to show that the TR of the 3D model that produces
  the best agreement with the CLASP observations has a relatively weak
  magnetic field and a relatively high degree of corrugation. We emphasize
  that a suitable way to validate or refute numerical models of the upper
  solar chromosphere is by confronting calculations and observations
  of the scattering polarization in ultraviolet lines sensitive to the
  Hanle effect.

Title: A Statistical Inference Method for Interpreting the CLASP
    Observations
Authors: Štěpán, J.; Trujillo Bueno, J.; Belluzzi, L.; Asensio
   Ramos, A.; Manso Sainz, R.; del Pino Alemán, T.; Casini, R.; Kano, R.;
   Winebarger, A.; Auchère, F.; Ishikawa, R.; Narukage, N.; Kobayashi,
   K.; Bando, T.; Katsukawa, Y.; Kubo, M.; Ishikawa, S.; Giono, G.; Hara,
   H.; Suematsu, Y.; Shimizu, T.; Sakao, T.; Tsuneta, S.; Ichimoto, K.;
   Cirtain, J.; Champey, P.; De Pontieu, B.; Carlsson, M.
Bibcode: 2018ApJ...865...48S
Altcode: 2018arXiv180802725S
  On 2015 September 3, the Chromospheric Lyman-Alpha SpectroPolarimeter
  (CLASP) successfully measured the linear polarization produced by
  scattering processes in the hydrogen Lyα line of the solar disk
  radiation, revealing conspicuous spatial variations in the Q/I and U/I
  signals. Via the Hanle effect, the line-center Q/I and U/I amplitudes
  encode information on the magnetic field of the chromosphere-corona
  transition region, but they are also sensitive to the three-dimensional
  structure of this corrugated interface region. With the help of a simple
  line-formation model, here we propose a statistical inference method
  for interpreting the Lyα line-center polarization observed by CLASP.

Title: Sunrise Chromospheric Infrared spectroPolarimeter (SCIP)
    for the SUNRISE balloon-borne solar observatory
Authors: Suematsu, Yoshinori; Katsukawa, Yukio; Hara, Hirohisa;
   Ichimoto, Kiyoshi; Shimizu, Toshifumi; Kubo, Masahito; Barthol,
   Peter; Riethmueller, Tino; Gandorfer, Achim; Feller, Alex; Orozco
   Suárez, David; Del Toro Iniesta, Jose Carlos; Kano, Ryouhei; Ishikawa,
   Shin-nosuke; Ishikawa, Ryohko; Tsuzuki, Toshihiro; Uraguchi, Fumihiro;
   Quintero Noda, Carlos; Tamura, Tomonori; Oba, Takayoshi; Kawabata,
   Yusuke; Nagata, Shinichi; Anan, Tetsu; Cobos Carrascosa, Juan Pedro;
   Lopez Jimenez, Antonio Carlos; Balaguer Jimenez, Maria; Solanki, Sami
Bibcode: 2018cosp...42E3285S
Altcode:
  The SUNRISE balloon-borne solar observatory carries a 1 m aperture
  optical telescope, and allows us to perform seeing-free continuous
  observations at visible-IR wavelengths from an altitude higher than
  35 km. In the past two flights, in 2009 and 2013, observations mainly
  focused on fine structures of photospheric magnetic fields. For the
  third flight planned for 2021, we are developing a new instrument
  for conducting spectro-polarimetry of spectral lines formed over a
  larger height range in the solar atmosphere from the photosphere to
  the chromosphere. Targets of the spectro-polarimetric observation
  are (1) to determine 3D magnetic structure from the photosphere to
  the chromosphere, (2) to trace MHD waves from the photosphere to the
  chromosphere, and (3) to reveal the mechanism driving chromospheric
  jets, by measuring height- and time-dependent velocities and magnetic
  fields. To achieve these goals, a spectro-polarimeter called SCIP
  (Sunrise Chromospheric Infrared spectroPolarimeter) is designed to
  observe near-infrared spectrum lines sensitive to solar magnetic
  fields. The spatial and spectral resolutions are 0.2 arcsec and
  200,000, respectively, while 0.03% polarimetric sensitivity is
  achieved within a 10 sec integration time. The optical system employs
  an Echelle grating and off-axis aspheric mirrors to observe the two
  wavelength ranges centered at 850 nm and 770 nm simultaneously by
  two cameras. Polarimetric measurements are performed using a rotating
  waveplate and polarization beam-splitters in front of the cameras. For
  detecting minute polarization signals with good precision, we carefully
  assess the temperature dependence of polarization optics, and make
  the opto-structural design that minimizes the thermal deformation
  of the spectrograph optics. Another key technique is to attain good
  (better than 30 msec) synchronization among the rotating phase of
  the waveplate, read-out timing of cameras, and step timing of a
  slit-scanning mirror. On-board accumulation and data processing are
  also critical because we cannot store all the raw data read-out from the
  cameras. We demonstrate that we can reduce the data down to almost 10%
  with loss-less image compression and without sacrificing polarimetric
  information in the data. The SCIP instrument is developed by internal
  collaboration among Japanese institutes including Japan Aerospace
  Exploration Agency (JAXA), the Spanish Sunrise consortium, and the
  German Max Planck Institute for Solar System Research (MPS) with a
  leadership of the National Astronomical Observatory of Japan (NAOJ).

Title: Current State of UV Spectro-Polarimetry and its Future
    Direction
Authors: Ishikawa, Ryohko; Sakao, Taro; Katsukawa, Yukio; Hara,
   Hirohisa; Ichimoto, Kiyoshi; Shimizu, Toshifumi; Kubo, Masahito;
   Auchere, Frederic; De Pontieu, Bart; Winebarger, Amy; Kobayashi,
   . Ken; Kano, Ryouhei; Narukage, Noriyuki; Trujillo Bueno, Javier;
   Song, Dong-uk; Manso Sainz, Rafael; Asensio Ramos, Andres; Leenaarts,
   Jorritt; Carlsson, Mats; Bando, Takamasa; Ishikawa, Shin-nosuke;
   Tsuneta, Saku; Belluzzi, Luca; Suematsu, Yoshinori; Giono, Gabriel;
   Yoshida, Masaki; Goto, Motoshi; Del Pino Aleman, Tanausu; Stepan,
   Jiri; Okamoto, Joten; Tsuzuki, Toshihiro; Uraguchi, Fumihiro; Champey,
   Patrick; Alsina Ballester, Ernest; Casini, Roberto; McKenzie, David;
   Rachmeler, Laurel; Bethge, Christian
Bibcode: 2018cosp...42E1564I
Altcode:
  To obtain quantitative information on the magnetic field in low beta
  regions (i.e., upper chromosphere and above) has been increasingly
  important to understand the energetic phenomena of the outer
  solar atmosphere such as flare, coronal heating, and the solar wind
  acceleration. In the UV range, there are abundant spectral lines that
  originate in the upper chromosphere and transition region. However,
  the Zeeman effect in these spectral lines does not give rise to easily
  measurable polarization signals because of the weak magnetic field
  strength and the larger Doppler broadening compared with the Zeeman
  effect. Instead, the Hanle effect in UV lines is expected to be a
  suitable diagnostic tool of the magnetic field in the upper atmospheric
  layers. To investigate the validity of UV spectro-polarimetry and
  the Hanle effect, the Chromospheric Lyman-Alpha Spectro-Polarimeter
  (CLASP), which is a NASA sounding- rocket experiment, was launched at
  White Sands in US on September 3, 2015. During its 5 minutes ballistic
  flight, it successfully performed spectro-polarimetric observations
  of the hydrogen Lyman-alpha line (121.57 nm) with an unprecedentedly
  high polarization sensitivity of 0.1% in this wavelength range. CLASP
  observed the linear polarization produced by scattering process in VUV
  lines for the first time and detected the polarization signals which
  indicate the operation of the Hanle effect. Following the success
  of CLASP, we are confident that UV spectro-polarimetry is the way
  to proceed, and we are planning the second flight of CLASP (CLASP2:
  Chromospheric LAyer SpectroPolarimeter 2). For this second flight we
  will carry out spectro-polarimetry in the Mg II h and k lines around
  280 nm, with minimum modifications of the CLASP1 instrument. The linear
  polarization in the Mg II k line is induced by scattering processes and
  the Hanle effect, being sensitive to magnetic field strengths of 5 to 50
  G. In addition, the circular polarizations in the Mg II h and k lines
  induced by the Zeeman effect can be measurable in at least plage and
  active regions. The combination of the Hanle and Zeeman effects could
  help us to more reliably infer the magnetic fields of the upper solar
  chromosphere. CLASP2 was selected for flight and is being developed for
  launch in the spring of 2019.Based on these sounding rocket experiments
  (CLASP1 and 2), we aim at establishing the strategy and refining the
  instrument concept for future space missions to explore the enigmatic
  atmospheric layers via UV spectro-polarimetry.

Title: Getting Ready for the Third Science Flight of SUNRISE
Authors: Barthol, Peter; Katsukawa, Yukio; Lagg, Andreas; Solanki,
   Sami K.; Kubo, Masahito; Riethmueller, Tino; Martínez Pillet,
   Valentin; Gandorfer, Achim; Feller, Alex; Berkefeld, . Thomas; Orozco
   Suárez, David; Del Toro Iniesta, Jose Carlos; Bernasconi, Pietro;
   Álvarez-Herrero, Alberto; Quintero Noda, Carlos
Bibcode: 2018cosp...42E.215B
Altcode:
  SUNRISE is a balloon-borne, stratospheric solar observatory dedicated
  to the investigation of the structure and dynamics of the Sun's
  magnetic field and its interaction with convective plasma flows and
  waves. The previous science flights of SUNRISE in 2009 and 2013 have
  led to many new scientific results, so far described in around 90
  refereed publications. This success has shown the huge potential of the
  SUNRISE concept and the recovery of the largely intact payload offers
  the opportunity for a third flight.The scientific instrumentation of
  SUNRISE 3 will have extended capabilities in particular to measure
  magnetic fields, plasma velocities and temperatures with increased
  sensitivity and over a larger height range in the solar atmosphere, from
  the convectively dominated photosphere up to the still poorly understood
  chromosphere. The latter is the key interaction region between magnetic
  field, waves and radiation and plays a central role in transporting
  energy to the outer layers of the solar atmosphere including the
  corona.SUNRISE 3 will carry 2 new grating-based spectro-polarimeters
  with slit-scanning and context imaging with slitjaw cameras. The
  SUNRISE UV Spectro-polarimeter and Imager (SUSI) will explore the rich
  near-UV range between 300 nm and 430 nm which is poorly accessible
  from the ground. The SUNRISE Chromospheric Infrared spectro-Polarimeter
  (SCIP) will sample 2 spectral windows in the near-infrared, containing
  many spectral lines highly sensitive to magnetic fields at different
  formation heights. In addition to the two new instruments the Imaging
  Magnetograph eXperiment (IMaX), an etalon-based tunable filtergraph and
  spectro-polarimeter flown on both previous missions, will be upgraded
  to IMaX+, enhancing its cadence and giving access to 2 spectral lines
  in the visible spectral range. All three instruments will allow
  investigating both the photosphere and the chromosphere and will
  ideally complement each other in terms of sensitivity, height coverage
  and resolution.A new gondola with a sophisticated attitude control
  system including roll damping will provide improved pointing/tracking
  performance. Upgraded image stabilization with higher bandwidth will
  further reduce residual jitter, maximizing the quality of the science
  data.SUNRISE 3 is a joint project of the German Max-Planck-Institut für
  Sonnensystemforschung together with the Spanish SUNRISE consortium, the
  Johns Hopkins University Applied Physics Laboratory, USA, the German
  Kiepenheuer Institut für Sonnenphysik, the National Astronomical
  Observatory of Japan and the Japan Aerospace eXploraion Agency (JAXA).

Title: Wavefront error measurements and alignment of CLASP2 telescope
    with a dual-band pass cold mirror coated primary mirror
Authors: Yoshida, Masaki; Song, Donguk; Ishikawa, Ryoko; Kano, Ryouhei;
   Katsukawa, Yukio; Suematsu, Yoshinori; Narukage, Noriyuki; Kubo,
   Masahito; Shinoda, Kazuya; Okamoto, Takenori J.; McKenzie, David E.;
   Rachmeler, Laurel A.; Auchère, Frédéric; Trujillo Bueno, Javier
Bibcode: 2018SPIE10699E..30Y
Altcode:
  "Chromospheric LAyer Spectro-Polarimeter (CLASP2)" is the next sounding
  rocket experiment of the "Chromospheric Lyman-Alpha Spectro-Polarimeter
  (CLASP)" that succeeded in observing for the first time the linear
  polarization spectra in the hydrogen Lyman-α line (121.6 nm) and is
  scheduled to be launched in 2019. In CLASP2, we will carry out full
  Stokes-vector spectropolarimetric observations in the Mg ii h and k
  lines near 280 nm with the spectro-polarimeter (SP), while imaging
  observations in the Lyman-α line will be conducted with the slitjaw
  optics (SJ). For the wavelength selection of CLASP2, the primary
  mirror of the telescope uses a new dual-band pass cold mirror coating
  targeting both at 121.6 nm and 280 nm. Therefore, we have to perform
  again the alignment of the telescope after the installation of the
  recoated primary mirror. Before unmounting the primary mirror from
  the telescope structure, we measured the wave-front error (WFE) of the
  telescope. The measured WFE map was consistent with what we had before
  the CLASP flight, clearly indicating that the telescope alignment has
  been maintained even after the flight. After the re-coated primary
  mirror was installed the WFE was measured, and coma aberration was
  found to be larger. Finally, the secondary mirror shim adjustments
  were carried out based on the WFE measurements. In CLASP2 telescope,
  we improved a fitting method of WFE map (applying 8th terms circular
  Zernike polynomial fitting instead of 37th terms circular Zernike
  fitting) and the improved method enables to achieve better performance
  than CLASP telescope. Indeed, WFE map obtained after the final shim
  adjustment indicated that the required specification (&lt; 5.5 μm
  RMS spot radius) that is more stringent than CLASP telescope was met.

Title: Solar polarimetry in the K I D<SUB>2</SUB> line : A novel
    possibility for a stratospheric balloon
Authors: Quintero Noda, C.; Villanueva, G. L.; Katsukawa, Y.; Solanki,
   S. K.; Orozco Suárez, D.; Ruiz Cobo, B.; Shimizu, T.; Oba, T.; Kubo,
   M.; Anan, T.; Ichimoto, K.; Suematsu, Y.
Bibcode: 2018A&A...610A..79Q
Altcode: 2018arXiv180101655Q
  Of the two solar lines, K I D<SUB>1</SUB> and D<SUB>2</SUB>, almost
  all attention so far has been devoted to the D<SUB>1</SUB> line, as
  D<SUB>2</SUB> is severely affected by an O<SUB>2</SUB> atmospheric
  band. This, however, makes the latter appealing for balloon and space
  observations from above (most of) the Earth's atmosphere. We estimate
  the residual effect of the O<SUB>2</SUB> band on the K I D<SUB>2</SUB>
  line at altitudes typical for stratospheric balloons. Our aim is to
  study the feasibility of observing the 770 nm window. Specifically,
  this paper serves as a preparation for the third flight of the Sunrise
  balloon-borne observatory. The results indicate that the absorption
  by O<SUB>2</SUB> is still present, albeit much weaker, at the expected
  balloon altitude. We applied the obtained O<SUB>2</SUB> transmittance
  to K I D<SUB>2</SUB> synthetic polarimetric spectra and found that in
  the absence of line-of-sight motions, the residual O<SUB>2</SUB> has
  a negligible effect on the K I D<SUB>2</SUB> line. On the other hand,
  for Doppler-shifted K I D<SUB>2</SUB> data, the residual O<SUB>2</SUB>
  might alter the shape of the Stokes profiles. However, the residual
  O<SUB>2</SUB> absorption is sufficiently weak at stratospheric levels
  that it can be divided out if appropriate measurements are made,
  something that is impossible at ground level. Therefore, for the
  first time with Sunrise III, we will be able to perform polarimetric
  observations of the K I D<SUB>2</SUB> line and, consequently, we will
  have improved access to the thermodynamics and magnetic properties of
  the upper photosphere from observations of the K I lines.

Title: From Hinode to the Next-Generation Solar Observation Missions
Authors: Ichimoto, Kiyoshi; Hara, Hirohisa; Katsukawa, Yukio;
   Ishikawa, Ryoko
Bibcode: 2018ASSL..449..231I
Altcode:
  No abstract at ADS

Title: Penumbral Microjets in Sunspot Chromospheres: Evidence of
    Magnetic Reconnection
Authors: Katsukawa, Yukio
Bibcode: 2018ASSL..449..201K
Altcode:
  No abstract at ADS

Title: Pointing stability of Hinode and requirements for the next
    Solar mission Solar-C
Authors: Katsukawa, Y.; Masada, Y.; Shimizu, T.; Sakai, S.; Ichimoto,
   K.
Bibcode: 2017SPIE10565E..28K
Altcode:
  It is essential to achieve fine pointing stability in a space mission
  aiming for high resolutional observations. In a future Japanese
  solar mission SOLAR-C, which is a successor of the HINODE (SOLAR-B)
  mission, we set targets of angular resolution better than 0.1 arcsec
  in the visible light and better than 0.2 - 0.5 arcsec in EUV and
  X-rays. These resolutions are twice to five times better than those of
  corresponding instruments onboard HINODE. To identify critical items
  to achieve the requirements of the pointing stability in SOLAR-C, we
  assessed in-flight performance of the pointing stability of HINODE that
  achieved the highest pointing stability in Japanese space missions. We
  realized that one of the critical items that have to be improved in
  SOLAR-C is performance of the attitude stability near the upper limit
  of the frequency range of the attitude control system. The stability
  of 0.1 arcsec (3σ) is required in the EUV and X-ray telescopes
  of SOLAR-C while the HINODE performance is slightly worse than the
  requirement. The visible light telescope of HINODE is equipped with
  an image stabilization system inside the telescope, which achieved
  the stability of 0.03 arcsec (3σ) by suppressing the attitude jitter
  in the frequency range lower than 10 Hz. For further improvement, it
  is expected to suppress disturbances induced by resonance between the
  telescope structures and disturbances of momentum wheels and mechanical
  gyros in the frequency range higher than 100 Hz.

Title: Instrument design and on-orbit performance of the solar
    optical telescope aboard hinode (Solar-B)
Authors: Suematsu, Yoshinori; Ichimoto, Kiyoshi; Katsukawa, Yukio;
   Tsuneta, Saku; Shimizu, Toshifumi
Bibcode: 2017SPIE10566E..2ZS
Altcode:
  The Solar Optical Telescope (SOT) aboard Solar-B satellite (Hinode)
  is designed to perform high-precision photometric and polarimetric
  observations of the solar lower atmosphere in visible light spectra
  (388-668 nm) with a spatial resolution of 0.2 to 0.3 arcsec. The
  SOT consists of two components; the optical telescope assembly (OTA)
  consisting of a 50-cm aperture Gregorian telescope with a collimating
  lens unit and an active tip-tilt mirror for an image-stabilization and
  an accompanying focal plane package (FPP) housing two filtergraphs and a
  spectro-polarimeter. Since its first-light observation on 25 Oct. 2006,
  the image-stabilization system has been working with performance
  better than 0.01 arcsec rms and the SOT has been continuously
  providing unprecedented solar data of high spatial resolution. Since
  the opto-mechanical and -thermal performance of the OTA is crucial
  to attain unprecedented high-quality solar observations, we here
  describe in detail the instrument design and on-orbit diffraction-limit
  performance of the OTA, the largest state-of-the-art solar telescope
  yet flown in space.

Title: Instrument design of 1.5-m aperture solar optical telescope
    for the Solar-C Mission
Authors: Suematsu, Yoshinori; Katsukawa, Yukio; Shimizu, Toshifumi;
   Ichimoto, Kiyoshi
Bibcode: 2017SPIE10564E..0TS
Altcode:
  A 1.5 m aperture optical telescope is planned for the next Japanese
  solar mission SOLAR-C as one of major three observing instruments. The
  optical telescope is designed to provide high-angular-resolution
  investigation of lower atmosphere from the photosphere to the uppermost
  chromosphere with enhanced spectroscopic and spectropolarimetric
  capability covering a wide wavelength region from 280 nm to 1100
  nm. The opto-mechanical and -thermal performance of the telescope is
  crucial to attain high-quality solar observations and we present a
  study of optical and structural design of the large aperture space
  solar telescope, together with conceptual design of its accompanying
  focal plane instruments: wide-band and narrow-band filtergraphs and
  a spectro-polarimeter for high spatial and temporal observations in
  the solar photospheric and chromospheric lines useful for sounding
  physical condition of dynamical phenomena.

Title: Chromospheric polarimetry through multiline observations of
    the 850-nm spectral region - II. A magnetic flux tube scenario
Authors: Quintero Noda, C.; Kato, Y.; Katsukawa, Y.; Oba, T.; de la
   Cruz Rodríguez, J.; Carlsson, M.; Shimizu, T.; Orozco Suárez, D.;
   Ruiz Cobo, B.; Kubo, M.; Anan, T.; Ichimoto, K.; Suematsu, Y.
Bibcode: 2017MNRAS.472..727Q
Altcode: 2017arXiv170801333Q
  In this publication, we continue the work started in Quintero Noda et
  al., examining this time a numerical simulation of a magnetic flux
  tube concentration. Our goal is to study if the physical phenomena
  that take place in it, in particular, the magnetic pumping, leaves
  a specific imprint on the examined spectral lines. We find that the
  profiles from the interior of the flux tube are periodically doppler
  shifted following an oscillation pattern that is also reflected in
  the amplitude of the circular polarization signals. In addition, we
  analyse the properties of the Stokes profiles at the edges of the flux
  tube discovering the presence of linear polarization signals for the Ca
  II lines, although they are weak with an amplitude around 0.5 per cent
  of the continuum intensity. Finally, we compute the response functions
  to perturbations in the longitudinal field, and we estimate the field
  strength using the weak-field approximation. Our results indicate
  that the height of formation of the spectral lines changes during the
  magnetic pumping process, which makes the interpretation of the inferred
  magnetic field strength and its evolution more difficult. These results
  complement those from previous works, demonstrating the capabilities and
  limitations of the 850-nm spectrum for chromospheric Zeeman polarimetry
  in a very dynamic and complex atmosphere.

Title: Optical and thermal design of 1.5-m aperture solar UV visible
    and IR observing telescope for Solar-C mission
Authors: Suematsu, Y.; Katsukawa, Y.; Shimizu, T.; Ichimoto, K.;
   Horiuchi, T.; Matsumoto, Y.; Takeyama, N.
Bibcode: 2017SPIE10565E..0RS
Altcode:
  The next Japanese solar mission, SOLAR-C, which has been envisaged
  after successful science operation of Hinode (SOLAR-B) mission, is
  perusing two plans: plan-A and plan-B, and under extensive study from
  science objectives as well as engineering point of view. The plan-A
  aims at performing out-of-ecliptic observations for investigating, with
  helioseismic approach, internal structure and dynamo mechanisms of the
  Sun. It also explores polar regions where fast solar wind is believed
  to originate. A baseline orbit for plan-A is a circular orbit of 1 AU
  distance from the Sun with its inclination at around or greater than
  40 degrees. The plan-B aims to study small-scale plasma processes and
  structures in the solar atmosphere which attract researchers' growing
  interest, followed by many Hinode discoveries [1], for understanding
  fully dynamism and magnetic nature of the atmosphere. With plan-B,
  high-angular-resolution investigation of the entire solar atmosphere
  (from the photosphere to the corona, including their interface layers,
  i.e., chromosphere and transition region) is to be performed with
  enhanced spectroscopic and spectro-polarimetric capability as compared
  with Hinode, together with enhanced sensitivity towards ultra-violet
  wavelengths. The orbit of plan-B is either a solar synchronous polar
  orbit of altitude around 600 km or a geosynchronous orbit to ensure
  continuous solar observations. After the decision of any one of the
  two plans, the SOLAR-C will be proposed for launch in mid-2010s. In
  this paper, we will present a basic design of one of major planned
  instrumental payload for the plan-B: the Solar Ultra-violet Visible
  and near IR observing Telescope (hereafter referred to as SUVIT). The
  basic concept in designing the SUVIT is to utilize as much as possible
  a heritage of successful telescope of the Solar Optical Telescope
  (SOT) aboard Hinode [2]. Major differences of SUVIT from SOT are
  the three times larger aperture of 1.5 m, which enables to collect
  one order of magnitude more photons than SOT, relatively shorter
  telescope length of 2.8 m to accommodate a launcher's nosecone size
  for possible dual-satellite-launch configuration, and much wider
  observing wavelength from UV (down to 250 nm) through near IR (up
  to 1100 nm). The large aperture is essentially important to attain
  scientific goals of the plan-B, especially for accurate diagnostics of
  the dynamic solar chromosphere as revealed by Hinode, although this
  make it difficult to design the telescope because of ten times more
  solar heat load introduced into the telescope. The SUVIT consists of
  two optically separable components; the telescope assembly (TA) and
  an accompanying focal plane package equipped with filtergraphs and
  spectrographs. Opto-mechanical and -thermal performance of the TA is
  crucial to attain high-quality solar observations and here we present
  a status of feasible study in its optical and thermal designing for
  diffraction-limited performance at visible wavelength in a reasonably
  wide field of view.

Title: Solar polarimetry through the K I lines at 770 nm
Authors: Quintero Noda, C.; Uitenbroek, H.; Katsukawa, Y.; Shimizu,
   T.; Oba, T.; Carlsson, M.; Orozco Suárez, D.; Ruiz Cobo, B.; Kubo,
   M.; Anan, T.; Ichimoto, K.; Suematsu, Y.
Bibcode: 2017MNRAS.470.1453Q
Altcode: 2017arXiv170510002Q
  We characterize the K I D<SUB>1</SUB> &amp; D<SUB>2</SUB> lines in
  order to determine whether they could complement the 850 nm window,
  containing the Ca II infrared triplet lines and several Zeeman sensitive
  photospheric lines, that was studied previously. We investigate the
  effect of partial redistribution on the intensity profiles, their
  sensitivity to changes in different atmospheric parameters, and
  the spatial distribution of Zeeman polarization signals employing a
  realistic magnetohydrodynamic simulation. The results show that these
  lines form in the upper photosphere at around 500 km, and that they
  are sensitive to the line-of-sight velocity and magnetic field strength
  at heights where neither the photospheric lines nor the Ca II infrared
  lines are. However, at the same time, we found that their sensitivity
  to the temperature essentially comes from the photosphere. Then, we
  conclude that the K I lines provide a complement to the lines in the
  850 nm window for the determination of atmospheric parameters in the
  upper photosphere, especially for the line-of-sight velocity and the
  magnetic field.

Title: CLASP/SJ Observations of Rapid Time Variations in the Lyα
    Emission in a Solar Active Region
Authors: Ishikawa, Shin-nosuke; Kubo, Masahito; Katsukawa, Yukio;
   Kano, Ryouhei; Narukage, Noriyuki; Ishikawa, Ryohko; Bando, Takamasa;
   Winebarger, Amy; Kobayashi, Ken; Trujillo Bueno, Javier; Auchère,
   Frédéric
Bibcode: 2017ApJ...846..127I
Altcode:
  The Chromospheric Lyα SpectroPolarimeter (CLASP) is a sounding
  rocket experiment launched on 2015 September 3 to investigate the
  solar chromosphere and transition region. The slit-jaw (SJ) optical
  system captured Lyα images with a high time cadence of 0.6 s. From
  the CLASP/SJ observations, many variations in the solar chromosphere
  and transition region emission with a timescale of &lt;1 minute
  were discovered. In this paper, we focus on the active region within
  the SJ field of view and investigate the relationship between short
  (&lt;30 s) temporal variations in the Lyα emission and the coronal
  structures observed by Solar Dynamics Observatory/Atmospheric Imaging
  Assembly (AIA). We compare the Lyα temporal variations at the coronal
  loop footpoints observed in the AIA 211 Å (≈2 MK) and AIA 171 Å
  (≈0.6 MK) channels with those in the regions with bright Lyα features
  without a clear association with the coronal loop footpoints. We find
  more short (&lt;30 s) temporal variations in the Lyα intensity in the
  footpoint regions. Those variations did not depend on the temperature
  of the coronal loops. Therefore, the temporal variations in the Lyα
  intensity at this timescale range could be related to the heating of
  the coronal structures up to temperatures around the sensitivity peak
  of 171 Å. No signature was found to support the scenario that these
  Lyα intensity variations were related to the nanoflares. Waves or
  jets from the lower layers (lower chromosphere or photosphere) are
  possible causes for this phenomenon.

Title: Indication of the Hanle Effect by Comparing the Scattering
    Polarization Observed by CLASP in the Lyα and Si III 120.65 nm Lines
Authors: Ishikawa, R.; Trujillo Bueno, J.; Uitenbroek, H.; Kubo, M.;
   Tsuneta, S.; Goto, M.; Kano, R.; Narukage, N.; Bando, T.; Katsukawa,
   Y.; Ishikawa, S.; Giono, G.; Suematsu, Y.; Hara, H.; Shimizu, T.;
   Sakao, T.; Winebarger, A.; Kobayashi, K.; Cirtain, J.; Champey, P.;
   Auchère, F.; Štěpán, J.; Belluzzi, L.; Asensio Ramos, A.; Manso
   Sainz, R.; De Pontieu, B.; Ichimoto, K.; Carlsson, M.; Casini, R.
Bibcode: 2017ApJ...841...31I
Altcode:
  The Chromospheric Lyman-Alpha Spectro-Polarimeter is a sounding
  rocket experiment that has provided the first successful measurement
  of the linear polarization produced by scattering processes in
  the hydrogen Lyα line (121.57 nm) radiation of the solar disk. In
  this paper, we report that the Si III line at 120.65 nm also shows
  scattering polarization and we compare the scattering polarization
  signals observed in the Lyα and Si III lines in order to search for
  observational signatures of the Hanle effect. We focus on four selected
  bright structures and investigate how the U/I spatial variations vary
  between the Lyα wing, the Lyα core, and the Si III line as a function
  of the total unsigned photospheric magnetic flux estimated from Solar
  Dynamics Observatory/Helioseismic and Magnetic Imager observations. In
  an internetwork region, the Lyα core shows an antisymmetric spatial
  variation across the selected bright structure, but it does not show
  it in other more magnetized regions. In the Si III line, the spatial
  variation of U/I deviates from the above-mentioned antisymmetric
  shape as the total unsigned photospheric magnetic flux increases. A
  plausible explanation of this difference is the operation of the Hanle
  effect. We argue that diagnostic techniques based on the scattering
  polarization observed simultaneously in two spectral lines with very
  different sensitivities to the Hanle effect, like Lyα and Si III,
  are of great potential interest for exploring the magnetism of the
  upper solar chromosphere and transition region.

Title: Polarization Calibration of the Chromospheric Lyman-Alpha
    SpectroPolarimeter for a 0.1% Polarization Sensitivity in the VUV
Range. Part II: In-Flight Calibration
Authors: Giono, G.; Ishikawa, R.; Narukage, N.; Kano, R.; Katsukawa,
   Y.; Kubo, M.; Ishikawa, S.; Bando, T.; Hara, H.; Suematsu, Y.;
   Winebarger, A.; Kobayashi, K.; Auchère, F.; Trujillo Bueno, J.;
   Tsuneta, S.; Shimizu, T.; Sakao, T.; Cirtain, J.; Champey, P.; Asensio
   Ramos, A.; Štěpán, J.; Belluzzi, L.; Manso Sainz, R.; De Pontieu,
   B.; Ichimoto, K.; Carlsson, M.; Casini, R.; Goto, M.
Bibcode: 2017SoPh..292...57G
Altcode:
  The Chromospheric Lyman-Alpha SpectroPolarimeter is a sounding
  rocket instrument designed to measure for the first time the linear
  polarization of the hydrogen Lyman-α line (121.6 nm). The instrument
  was successfully launched on 3 September 2015 and observations were
  conducted at the solar disc center and close to the limb during the
  five-minutes flight. In this article, the disc center observations are
  used to provide an in-flight calibration of the instrument spurious
  polarization. The derived in-flight spurious polarization is consistent
  with the spurious polarization levels determined during the pre-flight
  calibration and a statistical analysis of the polarization fluctuations
  from solar origin is conducted to ensure a 0.014% precision on the
  spurious polarization. The combination of the pre-flight and the
  in-flight polarization calibrations provides a complete picture of
  the instrument response matrix, and a proper error transfer method
  is used to confirm the achieved polarization accuracy. As a result,
  the unprecedented 0.1% polarization accuracy of the instrument in the
  vacuum ultraviolet is ensured by the polarization calibration.

Title: Discovery of Scattering Polarization in the Hydrogen Lyα
    Line of the Solar Disk Radiation
Authors: Kano, R.; Trujillo Bueno, J.; Winebarger, A.; Auchère, F.;
   Narukage, N.; Ishikawa, R.; Kobayashi, K.; Bando, T.; Katsukawa, Y.;
   Kubo, M.; Ishikawa, S.; Giono, G.; Hara, H.; Suematsu, Y.; Shimizu,
   T.; Sakao, T.; Tsuneta, S.; Ichimoto, K.; Goto, M.; Belluzzi, L.;
   Štěpán, J.; Asensio Ramos, A.; Manso Sainz, R.; Champey, P.;
   Cirtain, J.; De Pontieu, B.; Casini, R.; Carlsson, M.
Bibcode: 2017ApJ...839L..10K
Altcode: 2017arXiv170403228K
  There is a thin transition region (TR) in the solar atmosphere where
  the temperature rises from 10,000 K in the chromosphere to millions
  of degrees in the corona. Little is known about the mechanisms that
  dominate this enigmatic region other than the magnetic field plays a
  key role. The magnetism of the TR can only be detected by polarimetric
  measurements of a few ultraviolet (UV) spectral lines, the Lyα line
  of neutral hydrogen at 121.6 nm (the strongest line of the solar UV
  spectrum) being of particular interest given its sensitivity to the
  Hanle effect (the magnetic-field-induced modification of the scattering
  line polarization). We report the discovery of linear polarization
  produced by scattering processes in the Lyα line, obtained with
  the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) rocket
  experiment. The Stokes profiles observed by CLASP in quiet regions of
  the solar disk show that the Q/I and U/I linear polarization signals are
  of the order of 0.1% in the line core and up to a few percent in the
  nearby wings, and that both have conspicuous spatial variations with
  scales of ∼10 arcsec. These observations help constrain theoretical
  models of the chromosphere-corona TR and extrapolations of the
  magnetic field from photospheric magnetograms. In fact, the observed
  spatial variation from disk to limb of polarization at the line core
  and wings already challenge the predictions from three-dimensional
  magnetohydrodynamical models of the upper solar chromosphere.

Title: High-Reflectivity Coatings for a Vacuum Ultraviolet
    Spectropolarimeter
Authors: Narukage, Noriyuki; Kubo, Masahito; Ishikawa, Ryohko;
   Ishikawa, Shin-nosuke; Katsukawa, Yukio; Kobiki, Toshihiko; Giono,
   Gabriel; Kano, Ryouhei; Bando, Takamasa; Tsuneta, Saku; Auchère,
   Frédéric; Kobayashi, Ken; Winebarger, Amy; McCandless, Jim; Chen,
   Jianrong; Choi, Joanne
Bibcode: 2017SoPh..292...40N
Altcode:
  Precise polarization measurements in the vacuum ultraviolet (VUV)
  region are expected to be a new tool for inferring the magnetic fields
  in the upper atmosphere of the Sun. High-reflectivity coatings are key
  elements to achieving high-throughput optics for precise polarization
  measurements. We fabricated three types of high-reflectivity coatings
  for a solar spectropolarimeter in the hydrogen Lyman-α (Lyα ; 121.567
  nm) region and evaluated their performance. The first high-reflectivity
  mirror coating offers a reflectivity of more than 80 % in Lyα
  optics. The second is a reflective narrow-band filter coating that has
  a peak reflectivity of 57 % in Lyα , whereas its reflectivity in the
  visible light range is lower than 1/10 of the peak reflectivity (∼5
  % on average). This coating can be used to easily realize a visible
  light rejection system, which is indispensable for a solar telescope,
  while maintaining high throughput in the Lyα line. The third is a
  high-efficiency reflective polarizing coating that almost exclusively
  reflects an s-polarized beam at its Brewster angle of 68° with a
  reflectivity of 55 %. This coating achieves both high polarizing power
  and high throughput. These coatings contributed to the high-throughput
  solar VUV spectropolarimeter called the Chromospheric Lyman-Alpha
  SpectroPolarimeter (CLASP), which was launched on 3 September, 2015.

Title: Chromospheric polarimetry through multiline observations of
    the 850-nm spectral region
Authors: Quintero Noda, C.; Shimizu, T.; Katsukawa, Y.; de la Cruz
   Rodríguez, J.; Carlsson, M.; Anan, T.; Oba, T.; Ichimoto, K.;
   Suematsu, Y.
Bibcode: 2017MNRAS.464.4534Q
Altcode: 2016arXiv161006651Q
  Future solar missions and ground-based telescopes aim to understand the
  magnetism of the solar chromosphere. We performed a supporting study in
  Quintero Noda et al. focused on the infrared Ca II 8542 Å line and we
  concluded that it is one of the best candidates because it is sensitive
  to a large range of atmospheric heights, from the photosphere to the
  middle chromosphere. However, we believe that it is worth trying to
  improve the results produced by this line observing additional spectral
  lines. In that regard, we examined the neighbourhood solar spectrum
  looking for spectral lines which could increase the sensitivity to
  the atmospheric parameters. Interestingly, we discovered several
  photospheric lines which greatly improve the photospheric sensitivity
  to the magnetic field vector. Moreover, they are located close to a
  second chromospheric line which also belongs to the Ca II infrared
  triplet, I.e. the Ca II 8498 Å line, and enhances the sensitivity to
  the atmospheric parameters at chromospheric layers. We conclude that the
  lines in the vicinity of the Ca II 8542 Å line not only increase its
  sensitivity to the atmospheric parameters at all layers, but also they
  constitute an excellent spectral window for chromospheric polarimetry.

Title: Various Local Heating Events in the Earliest Phase of Flux
    Emergence
Authors: Toriumi, Shin; Katsukawa, Yukio; Cheung, Mark C. M.
Bibcode: 2017ApJ...836...63T
Altcode: 2017arXiv170101446T
  Emerging flux regions (EFRs) are known to exhibit various sporadic
  local heating events in the lower atmosphere. To investigate the
  characteristics of these events, especially to link the photospheric
  magnetic fields and atmospheric dynamics, we analyze Hinode, Interface
  Region Imaging Spectrograph (IRIS), and Solar Dynamics Observatory
  data of a new EFR in NOAA AR 12401. Out of 151 bright points (BPs)
  identified in Hinode/SOT Ca images, 29 are overlapped by an SOT/SP
  scan. Seven BPs in the EFR center possess mixed-polarity magnetic
  backgrounds in the photosphere. Their IRIS UV spectra (e.g., Si IV
  1402.8 Å) are strongly enhanced and red- or blueshifted, with tails
  reaching +/- 150 {km} {{{s}}}<SUP>-1</SUP>, which is highly suggestive
  of bi-directional jets; each brightening lasts for 10-15 minutes,
  leaving flare-like light curves. Most of this group show bald patches,
  the U-shaped photospheric magnetic loops. Another 10 BPs are found in
  unipolar regions at the EFR edges. They are generally weaker in UV
  intensities and exhibit systematic redshifts with Doppler speeds up
  to 40 {km} {{{s}}}<SUP>-1</SUP>, which could exceed the local sound
  speed in the transition region. Both types of BPs show signs of strong
  temperature increase in the low chromosphere. These observational
  results support the physical picture that heating events in the EFR
  center are due to magnetic reconnection within cancelling undular
  fields like Ellerman bombs, while the peripheral heating events are
  due to shocks or strong compressions caused by fast downflows along
  the overlying arch filament system.

Title: Polarization Calibration of the Chromospheric Lyman-Alpha
    SpectroPolarimeter for a 0.1 % Polarization Sensitivity in the VUV
Range. Part I: Pre-flight Calibration
Authors: Giono, G.; Ishikawa, R.; Narukage, N.; Kano, R.; Katsukawa,
   Y.; Kubo, M.; Ishikawa, S.; Bando, T.; Hara, H.; Suematsu, Y.;
   Winebarger, A.; Kobayashi, K.; Auchère, F.; Trujillo Bueno, J.
Bibcode: 2016SoPh..291.3831G
Altcode: 2016SoPh..tmp..177G
  The Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP) is a sounding
  rocket experiment designed to measure for the first time the linear
  polarization of the hydrogen Lyman-α line (121.6 nm) and requires
  a 0.1 % polarization sensitivity, which is unprecedented for a
  spectropolarimeter in the vacuum UV (VUV) spectral range.

Title: Discovery of Ubiquitous Fast-Propagating Intensity Disturbances
    by the Chromospheric Lyman Alpha Spectropolarimeter (CLASP)
Authors: Kubo, M.; Katsukawa, Y.; Suematsu, Y.; Kano, R.; Bando,
   T.; Narukage, N.; Ishikawa, R.; Hara, H.; Giono, G.; Tsuneta, S.;
   Ishikawa, S.; Shimizu, T.; Sakao, T.; Winebarger, A.; Kobayashi, K.;
   Cirtain, J.; Champey, P.; Auchère, F.; Trujillo Bueno, J.; Asensio
   Ramos, A.; Štěpán, J.; Belluzzi, L.; Manso Sainz, R.; De Pontieu,
   B.; Ichimoto, K.; Carlsson, M.; Casini, R.; Goto, M.
Bibcode: 2016ApJ...832..141K
Altcode:
  High-cadence observations by the slit-jaw (SJ) optics system of the
  sounding rocket experiment known as the Chromospheric Lyman Alpha
  Spectropolarimeter (CLASP) reveal ubiquitous intensity disturbances
  that recurrently propagate in either the chromosphere or the transition
  region or both at a speed much higher than the speed of sound. The
  CLASP/SJ instrument provides a time series of two-dimensional images
  taken with broadband filters centered on the Lyα line at a 0.6 s
  cadence. The multiple fast-propagating intensity disturbances appear in
  the quiet Sun and in an active region, and they are clearly detected in
  at least 20 areas in a field of view of 527″ × 527″ during the 5
  minute observing time. The apparent speeds of the intensity disturbances
  range from 150 to 350 km s<SUP>-1</SUP>, and they are comparable
  to the local Alfvén speed in the transition region. The intensity
  disturbances tend to propagate along bright elongated structures away
  from areas with strong photospheric magnetic fields. This suggests
  that the observed fast-propagating intensity disturbances are related
  to the magnetic canopy structures. The maximum distance traveled by
  the intensity disturbances is about 10″, and the widths are a few
  arcseconds, which are almost determined by a pixel size of 1.″03. The
  timescale of each intensity pulse is shorter than 30 s. One possible
  explanation for the fast-propagating intensity disturbances observed
  by CLASP is magnetohydrodynamic fast-mode waves.

Title: Analysis of a spatially deconvolved solar pore
Authors: Quintero Noda, C.; Shimizu, T.; Ruiz Cobo, B.; Suematsu,
   Y.; Katsukawa, Y.; Ichimoto, K.
Bibcode: 2016MNRAS.460.1476Q
Altcode: 2016arXiv160501796Q; 2016MNRAS.tmp..847Q
  Solar pores are active regions with large magnetic field strengths
  and apparent simple magnetic configurations. Their properties
  resemble the ones found for the sunspot umbra although pores do
  not show penumbra. Therefore, solar pores present themselves as an
  intriguing phenomenon that is not completely understood. We examine
  in this work a solar pore observed with Hinode/SP using two state
  of the art techniques. The first one is the spatial deconvolution
  of the spectropolarimetric data that allows removing the stray
  light contamination induced by the spatial point spread function
  of the telescope. The second one is the inversion of the Stokes
  profiles assuming local thermodynamic equilibrium that let us to
  infer the atmospheric physical parameters. After applying these
  techniques, we found that the spatial deconvolution method does not
  introduce artefacts, even at the edges of the magnetic structure,
  where large horizontal gradients are detected on the atmospheric
  parameters. Moreover, we also describe the physical properties of
  the magnetic structure at different heights finding that, in the
  inner part of the solar pore, the temperature is lower than outside,
  the magnetic field strength is larger than 2 kG and unipolar, and
  the line-of-sight velocity is almost null. At neighbouring pixels,
  we found low magnetic field strengths of same polarity and strong
  downward motions that only occur at the low photosphere, below the
  continuum optical depth log τ = -1. Finally, we studied the spatial
  relation between different atmospheric parameters at different heights
  corroborating the physical properties described before.

Title: Optical alignment of the Chromospheric Lyman-Alpha
    Spectro-Polarimeter using sophisticated methods to minimize activities
    under vacuum
Authors: Giono, G.; Katsukawa, Y.; Ishikawa, R.; Narukage, N.;
   Kano, R.; Kubo, M.; Ishikawa, S.; Bando, T.; Hara, H.; Suematsu, Y.;
   Winebarger, A.; Kobayashi, K.; Auchère, F.; Trujillo Bueno, J.
Bibcode: 2016SPIE.9905E..3DG
Altcode:
  The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a
  sounding-rocket instrument developed at the National Astronomical
  Observatory of Japan (NAOJ) as a part of an international
  collaboration. The instrument main scientific goal is to achieve
  polarization measurement of the Lyman-α line at 121.56 nm emitted from
  the solar upper-chromosphere and transition region with an unprecedented
  0.1% accuracy. The optics are composed of a Cassegrain telescope
  coated with a "cold mirror" coating optimized for UV reflection and
  a dual-channel spectrograph allowing for simultaneous observation of
  the two orthogonal states of polarization. Although the polarization
  sensitivity is the most important aspect of the instrument, the spatial
  and spectral resolutions of the instrument are also crucial to observe
  the chromospheric features and resolve the Ly-α profiles. A precise
  alignment of the optics is required to ensure the resolutions, but
  experiments under vacuum conditions are needed since Ly-α is absorbed
  by air, making the alignment experiments difficult. To bypass this
  issue, we developed methods to align the telescope and the spectrograph
  separately in visible light. We explain these methods and present
  the results for the optical alignment of the CLASP telescope and
  spectrograph. We then discuss the combined performances of both parts
  to derive the expected resolutions of the instrument, and compare them
  with the flight observations performed on September 3<SUP>rd</SUP> 2015.

Title: Development of a near-infrared detector and a fiber-optic
    integral field unit for a space solar observatory SOLAR-C
Authors: Katsukawa, Yukio; Kamata, Yukiko; Anan, Tetsu; Hara,
   Hirohisa; Suematsu, Yoshinori; Bando, Takamasa; Ichimoto, Kiyoshi;
   Shimizu, Toshifumi
Bibcode: 2016SPIE.9904E..5IK
Altcode:
  We are developing a high sensitivity and fast readout near-infrared
  (NIR) detector and an integral field unit (IFU) for making
  spectro-polarimetric observations of rapidly varying chromospheric
  spectrum lines, such as He I 1083 nm and Ca II 854 nm, in the
  next space-based solar mission SOLAR-C. We made tests of a 1.7 μm
  cutoff H2RG detector with the SIDECAR ASIC for the application in
  SOLAR-C. It's important to verify its perfor- mance in the temperature
  condition around -100 °C, which is hotter than the typical temperature
  environment used for a NIR detector. We built a system for testing the
  detector between -70 °C and -140 °C. We verified linearity, read-out
  noise, and dark current in both the slow and fast readout modes. We
  found the detector has to be cooled down lower than -100 °C because
  of significant increase of the number of hot pixels in the hotter
  environment. The compact and polarization maintenance IFU was designed
  using fiber-optic ribbons consisting of rectangular cores which exhibit
  good polarization maintenance. A Silicone adhesive DC-SE9187L was used
  to hold the fragile fiber-optic ribbons in a metal housing. Polarization
  maintenance property was confirmed though polarization calibration
  as well as temperature control are required to suppress polarization
  crosstalk and to achieve the polarization accuracy in SOLAR-C.

Title: Spectropolarimetric capabilities of Ca II 8542 Å line
Authors: Quintero Noda, C.; Shimizu, T.; de la Cruz Rodríguez, J.;
   Katsukawa, Y.; Ichimoto, K.; Anan, T.; Suematsu, Y.
Bibcode: 2016MNRAS.459.3363Q
Altcode: 2016MNRAS.tmp..667Q; 2016arXiv160404957Q
  The next generation of space- and ground-based solar missions aim
  to study the magnetic properties of the solar chromosphere using the
  infrared Ca II lines and the He I 10830 Å line. The former seem to be
  the best candidates to study the stratification of magnetic fields in
  the solar chromosphere and their relation to the other thermodynamical
  properties underlying the chromospheric plasma. The purpose of this
  work is to provide a detailed analysis of the diagnostic capabilities
  of the Ca II 8542 Å line, anticipating forthcoming observational
  facilities. We study the sensitivity of the Ca II 8542 Å line
  to perturbations applied to the physical parameters of reference
  semi-empirical 1D model atmospheres using response functions and we
  make use of 3D magnetohydrodynamics simulations to examine the expected
  polarization signals for moderate magnetic field strengths. Our results
  indicate that the Ca II 8542 Å line is mostly sensitive to the layers
  enclosed in the range log τ = [0, -5.5], under the physical conditions
  that are present in our model atmospheres. In addition, the simulated
  magnetic flux tube generates strong longitudinal signals in its centre
  and moderate transversal signals, due to the vertical expansion of
  magnetic field lines, in its edge. Thus, observing the Ca II 8542 Å
  line we will be able to infer the 3D geometry of moderate magnetic
  field regions.

Title: Flux appearance and disappearance rates in the solar
    internetwork
Authors: Gosic, Milan; Bellot Rubio, Luis; Del Toro Iniesta, Jose
   Carlos; Orozco Suarez, David; Katsukawa, Yukio
Bibcode: 2016SPD....4740105G
Altcode:
  The solar internetwork contains weak and highly dynamic magnetic
  fields that are essential to understanding the solar magnetism at small
  spatial and temporal scales. Therefore, it is important to determine
  how these fields are maintained on the solar surface. Using unique
  Hinode observations, we follow the evolution of individual magnetic
  elements in the interior of two supergranular cells at the disk
  center. From up to 38 hr of continuous measurements, we show that
  magnetic flux appears in internetwork regions at a rate of 120±3
  Mx cm<SUP>-2</SUP> day<SUP>-1</SUP> (3.7±0.4 × 10<SUP>24</SUP> Mx
  day<SUP>-1</SUP> over the entire solar surface). Flux disappears from
  the internetwork at a rate of 125±6 Mx cm<SUP>-2</SUP> day<SUP>-1</SUP>
  (3.9±0.5 × 10<SUP>24</SUP> Mx day<SUP>-1</SUP>) through fading of
  magnetic elements, cancellation between opposite-polarity features,
  and interactions with network patches, which converts internetwork
  elements into network features. The removal of flux from supergranules
  occurs mainly through fading and interactions with network, at nearly
  the same rate of about 50 Mx cm<SUP>-2</SUP> day<SUP>-1</SUP>. Our
  results demonstrate that the sources and sinks of internetwork magnetic
  flux are well balanced, reflecting the steady-state nature of the quiet
  Sun. Using the instantaneous flux appearance and disappearance rates,
  we successfully reproduce, for the first time, the temporal evolution
  of the total unsigned flux in the interior of supergranular cells.

Title: Spectro-polarimetric observation in UV with CLASP to probe
    the chromosphere and transition region
Authors: Kano, Ryouhei; Ishikawa, Ryohko; Winebarger, Amy R.; Auchère,
   Frédéric; Trujillo Bueno, Javier; Narukage, Noriyuki; Kobayashi,
   Ken; Bando, Takamasa; Katsukawa, Yukio; Kubo, Masahito; Ishikawa,
   Shin-Nosuke; Giono, Gabriel; Hara, Hirohisa; Suematsu, Yoshinori;
   Shimizu, Toshifumi; Sakao, Taro; Tsuneta, Saku; Ichimoto, Kiyoshi;
   Goto, Motoshi; Cirtain, Jonathan W.; De Pontieu, Bart; Casini, Roberto;
   Manso Sainz, Rafael; Asensio Ramos, Andres; Stepan, Jiri; Belluzzi,
   Luca; Carlsson, Mats
Bibcode: 2016SPD....4710107K
Altcode:
  The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a NASA
  sounding-rocket experiment that was performed in White Sands in
  the US on September 3, 2015. During its 5-minute ballistic flight,
  CLASP successfully made the first spectro-polarimetric observation in
  the Lyman-alpha line (121.57 nm) originating in the chromosphere and
  transition region. Since the Lyman-alpha polarization is sensitive
  to magnetic field of 10-100 G by the Hanle effect, we aim to infer
  the magnetic field information in such upper solar atmosphere with
  this experiment.The obtained CLASP data showed that the Lyman-alpha
  scattering polarization is about a few percent in the wings and
  the order of 0.1% in the core near the solar limb, as it had been
  theoretically predicted, and that both polarization signals have a
  conspicuous spatio-temporal variability. CLASP also observed another
  upper-chromospheric line, Si III (120.65 nm), whose critical field
  strength for the Hanle effect is 290 G, and showed a measurable
  scattering polarization of a few % in this line. The polarization
  properties of the Si III line could facilitate the interpretation of
  the scattering polarization observed in the Lyman-alpha line.In this
  presentation, we would like to show how the upper chromosphere and
  transition region are seen in the polarization of these UV lines and
  discuss the possible source of these complicated polarization signals.

Title: The Solar Internetwork. II. Flux Appearance and Disappearance
    Rates
Authors: Gošić, M.; Bellot Rubio, L. R.; del Toro Iniesta, J. C.;
   Orozco Suárez, D.; Katsukawa, Y.
Bibcode: 2016ApJ...820...35G
Altcode: 2016arXiv160205892G
  Small-scale internetwork magnetic fields are important ingredients of
  the quiet Sun. In this paper we analyze how they appear and disappear
  on the solar surface. Using high resolution Hinode magnetograms,
  we follow the evolution of individual magnetic elements in the
  interior of two supergranular cells at the disk center. From up to
  38 hr of continuous measurements, we show that magnetic flux appears
  in internetwork regions at a rate of 120 ± 3 Mx cm<SUP>-2</SUP>
  day<SUP>-1</SUP> (3.7 ± 0.4 × 10<SUP>24</SUP> Mx day<SUP>-1</SUP>
  over the entire solar surface). Flux disappears from the internetwork
  at a rate of 125 ± 6 Mx cm<SUP>-2</SUP> day<SUP>-1</SUP> (3.9
  ± 0.5 × 10<SUP>24</SUP> Mx day<SUP>-1</SUP>) through fading of
  magnetic elements, cancelation between opposite-polarity features,
  and interactions with network patches, which converts internetwork
  elements into network features. Most of the flux is lost through
  fading and interactions with the network, at nearly the same rate of
  about 50 Mx cm<SUP>-2</SUP> day<SUP>-1</SUP>. Our results demonstrate
  that the sources and sinks of internetwork magnetic flux are well
  balanced. Using the instantaneous flux appearance and disappearance
  rates, we successfully reproduce the time evolution of the total
  unsigned flux in the two supergranular cells.

Title: Light Bridge in a Developing Active Region. II. Numerical
    Simulation of Flux Emergence and Light Bridge Formation
Authors: Toriumi, Shin; Cheung, Mark C. M.; Katsukawa, Yukio
Bibcode: 2015ApJ...811..138T
Altcode: 2015arXiv150900205T
  Light bridges, the bright structure dividing umbrae in sunspot regions,
  show various activity events. In Paper I, we reported on an analysis
  of multi-wavelength observations of a light bridge in a developing
  active region (AR) and concluded that the activity events are caused
  by magnetic reconnection driven by magnetconvective evolution. The
  aim of this second paper is to investigate the detailed magnetic and
  velocity structures and the formation mechanism of light bridges. For
  this purpose, we analyze numerical simulation data from a radiative
  magnetohydrodynamics model of an emerging AR. We find that a weakly
  magnetized plasma upflow in the near-surface layers of the convection
  zone is entrained between the emerging magnetic bundles that appear
  as pores at the solar surface. This convective upflow continuously
  transports horizontal fields to the surface layer and creates a light
  bridge structure. Due to the magnetic shear between the horizontal
  fields of the bridge and the vertical fields of the ambient pores,
  an elongated cusp-shaped current layer is formed above the bridge,
  which may be favorable for magnetic reconnection. The striking
  correspondence between the observational results of Paper I and the
  numerical results of this paper provides a consistent physical picture
  of light bridges. The dynamic activity phenomena occur as a natural
  result of the bridge formation and its convective nature, which has
  much in common with those of umbral dots and penumbral filaments.

Title: Light Bridge in a Developing Active Region. I. Observation
    of Light Bridge and its Dynamic Activity Phenomena
Authors: Toriumi, Shin; Katsukawa, Yukio; Cheung, Mark C. M.
Bibcode: 2015ApJ...811..137T
Altcode: 2015arXiv150900183T
  Light bridges, the bright structures that divide the umbra of sunspots
  and pores into smaller pieces, are known to produce a wide variety
  of activity events in solar active regions (ARs). It is also known
  that the light bridges appear in the assembling process of nascent
  sunspots. The ultimate goal of this series of papers is to reveal
  the nature of light bridges in developing ARs and the occurrence of
  activity events associated with the light bridge structures from
  both observational and numerical approaches. In this first paper,
  exploiting the observational data obtained by Hinode, the Interface
  Region Imaging Spectrograph, and the Solar Dynamics Observatory, we
  investigate the detailed structure of the light bridge in NOAA AR 11974
  and its dynamic activity phenomena. As a result, we find that the light
  bridge has a weak, horizontal magnetic field, which is transported from
  the interior by a large-scale convective upflow and is surrounded by
  strong, vertical fields of adjacent pores. In the chromosphere above the
  bridge, a transient brightening occurs repeatedly and intermittently,
  followed by a recurrent dark surge ejection into higher altitudes. Our
  analysis indicates that the brightening is the plasma heating due
  to magnetic reconnection at lower altitudes, while the dark surge is
  the cool, dense plasma ejected from the reconnection region. From the
  observational results, we conclude that the dynamic activity observed
  in a light bridge structure such as chromospheric brightenings and dark
  surge ejections are driven by magnetoconvective evolution within the
  light bridge and its interaction with the surrounding magnetic fields.

Title: CLASP: A UV Spectropolarimeter on a Sounding Rocket for
    Probing theChromosphere-Corona Transition Regio
Authors: Ishikawa, Ryohko; Kano, Ryouhei; Winebarger, Amy; Auchere,
   Frederic; Trujillo Bueno, Javier; Bando, Takamasa; Narukage,
   Noriyuki; Kobayashi, Ken; Katsukawa, Yukio; Kubo, Masahito; Ishikawa,
   Shin-nosuke; Giono, Gabriel; Tsuneta, Saku; Hara, Hirohisa; Suematsu,
   Yoshinori; Shimizu, Toshifumi; Sakao, Taro; Ichimoto, Kiyoshi;
   Cirtain, Jonathan; De Pontieu, Bart; Casini, Roberto; Manso Sainz,
   Rafael; Asensio Ramos, Andres; Stepan, Jiri; Belluzzi, Luca
Bibcode: 2015IAUGA..2254536I
Altcode:
  The wish to understand the energetic phenomena of the outer solar
  atmosphere makes it increasingly important to achieve quantitative
  information on the magnetic field in the chromosphere-corona
  transition region. To this end, we need to measure and model the
  linear polarization produced by scattering processes and the Hanle
  effect in strong UV resonance lines, such as the hydrogen Lyman-alpha
  line. A team consisting of Japan, USA, Spain, France, and Norway has
  been developing a sounding rocket experiment called the Chromospheric
  Lyman-alpha Spectro-Polarimeter (CLASP). The aim is to detect the
  scattering polarization produced by anisotropic radiation pumping in
  the hydrogen Lyman-alpha line (121.6 nm), and via the Hanle effect to
  try to constrain the magnetic field vector in the upper chromosphere
  and transition region. In this talk, we will present an overview
  of our CLASP mission, its scientific objectives, ground tests made,
  and the latest information on the launch planned for the Summer of 2015.

Title: The Solar Internetwork. I. Contribution to the Network
    Magnetic Flux
Authors: Gošić, M.; Bellot Rubio, L. R.; Orozco Suárez, D.;
   Katsukawa, Y.; del Toro Iniesta, J. C.
Bibcode: 2014ApJ...797...49G
Altcode: 2014arXiv1408.2369G
  The magnetic network (NE) observed on the solar surface harbors a
  sizable fraction of the total quiet Sun flux. However, its origin and
  maintenance are not well known. Here we investigate the contribution
  of internetwork (IN) magnetic fields to the NE flux. IN fields permeate
  the interior of supergranular cells and show large emergence rates. We
  use long-duration sequences of magnetograms acquired by Hinode and
  an automatic feature tracking algorithm to follow the evolution of NE
  and IN flux elements. We find that 14% of the quiet Sun (QS) flux is
  in the form of IN fields with little temporal variations. IN elements
  interact with NE patches and modify the flux budget of the NE either
  by adding flux (through merging processes) or by removing it (through
  cancellation events). Mergings appear to be dominant, so the net flux
  contribution of the IN is positive. The observed rate of flux transfer
  to the NE is 1.5 × 10<SUP>24</SUP> Mx day<SUP>-1</SUP> over the entire
  solar surface. Thus, the IN supplies as much flux as is present in the
  NE in only 9-13 hr. Taking into account that not all the transferred
  flux is incorporated into the NE, we find that the IN would be able
  to replace the entire NE flux in approximately 18-24 hr. This renders
  the IN the most important contributor to the NE, challenging the view
  that ephemeral regions are the main source of flux in the QS. About 40%
  of the total IN flux eventually ends up in the NE.

Title: Precision VUV Spectro-Polarimetry for Solar Chromospheric
    Magnetic Field Measurements
Authors: Ishikawa, R.; Bando, T.; Hara, H.; Ishikawa, S.; Kano, R.;
   Kubo, M.; Katsukawa, Y.; Kobiki, T.; Narukage, N.; Suematsu, Y.;
   Tsuneta, S.; Aoki, K.; Miyagawa, K.; Ichimoto, K.; Kobayashi, K.;
   Auchère, F.; Clasp Team
Bibcode: 2014ASPC..489..319I
Altcode:
  The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a VUV
  spectro-polarimeter optimized for measuring the linear polarization
  of the Lyman-α line (121.6 nm) to be launched in 2015 with NASA's
  sounding rocket (Ishikawa et al. 2011; Narukage et al. 2011; Kano et
  al. 2012; Kobayashi et al. 2012). With this experiment, we aim to (1)
  observe the scattering polarization in the Lyman-α line, (2) detect
  the Hanle effect, and (3) assess the magnetic fields in the upper
  chromosphere and transition region for the first time. The polarization
  measurement error consists of scale error δ a (error in amplitude
  of linear polarization), azimuth error Δφ (error in the direction
  of linear polarization), and spurious polarization ɛ (false linear
  polarization signals). The error ɛ should be suppressed below 0.1%
  in the Lyman-α core (121.567 nm ±0.02 nm), and 0.5% in the Lyman-α
  wing (121.567 nm ±0.05 nm), based on our scientific requirements shown
  in Table 2 of Kubo et al. (2014). From scientific justification, we
  adopt Δ φ&lt;2° and δ a&lt;10% as the instrument requirements. The
  spectro-polarimeter features a continuously rotating MgF<SUB>2</SUB>
  waveplate (Ishikawa et al. 2013), a dual-beam spectrograph with a
  spherical grating working also as a beam splitter, and two polarization
  analyzers (Bridou et al. 2011), which are mounted at 90 degree from
  each other to measure two orthogonal polarization simultaneously. For
  the optical layout of the CLASP instrument, see Figure 3 in Kubo et
  al. (2014). Considering the continuous rotation of the half-waveplate,
  the modulation efficiency is 0.64 both for Stokes Q and U. All the raw
  data are returned and demodulation (successive addition or subtraction
  of images) is done on the ground. <P />We control the CLASP polarization
  performance in the following three steps. First, we evaluate the
  throughput and polarization properties of each optical component in
  the Lyman-α line, using the Ultraviolet Synchrotron ORbital Radiation
  Facility (UVSOR) at the Institute for Molecular Science. The second
  step is polarization calibration of the spectro-polarimeter after
  alignment. Since the spurious polarization caused by the axisymmetric
  telescope is estimated to be negligibly small because of the symmetry
  (Ishikawa et al. 2014), we do not perform end-to-end polarization
  calibration. As the final step, before the scientific observation near
  the limb, we make a short observation at the Sun center and verify
  the polarization sensitivity, because the scattering polarization
  is expected to be close to zero at the Sun center due to symmetric
  geometry. In order to clarify whether we will be able to achieve the
  required polarization sensitivity and accuracy via these steps, we
  exercise polarization error budget, by investigating all the possible
  causes and their magnitudes of polarization errors, all of which are not
  necessarily verified by the polarization calibration. Based on these
  error budgets, we conclude that a polarization sensitivity of 0.1% in
  the line core, δ a&lt;10% and Δ φ&lt;2° can be achieved combined
  with the polarization calibration of the spectro-polarimeter and the
  onboard calibration at the Sun center(refer to Ishikawa et al. 2014,
  for the detail). <P />We are currently conducting verification tests
  of the flight components and development of the UV light source for
  the polarization calibration. From 2014 spring, we will begin the
  integration, alignment, and calibration. We will update the error
  budgets throughout the course of these tests.

Title: A Sounding Rocket Experiment for the Chromospheric Lyman-Alpha
    Spectro-Polarimeter (CLASP)
Authors: Kubo, M.; Kano, R.; Kobayashi, K.; Bando, T.; Narukage, N.;
   Ishikawa, R.; Tsuneta, S.; Katsukawa, Y.; Ishikawa, S.; Suematsu, Y.;
   Hara, H.; Shimizu, T.; Sakao, T.; Ichimoto, K.; Goto, M.; Holloway,
   T.; Winebarger, A.; Cirtain, J.; De Pontieu, B.; Casini, R.; Auchère,
   F.; Trujillo Bueno, J.; Manso Sainz, R.; Belluzzi, L.; Asensio Ramos,
   A.; Štěpán, J.; Carlsson, M.
Bibcode: 2014ASPC..489..307K
Altcode:
  A sounding-rocket experiment called the Chromospheric Lyman-Alpha
  Spectro-Polarimeter (CLASP) is presently under development to measure
  the linear polarization profiles in the hydrogen Lyman-alpha (Lyα)
  line at 121.567 nm. CLASP is a vacuum-UV (VUV) spectropolarimeter to aim
  for first detection of the linear polarizations caused by scattering
  processes and the Hanle effect in the Lyα line with high accuracy
  (0.1%). This is a fist step for exploration of magnetic fields in
  the upper chromosphere and transition region of the Sun. Accurate
  measurements of the linear polarization signals caused by scattering
  processes and the Hanle effect in strong UV lines like Lyα are
  essential to explore with future solar telescopes the strength
  and structures of the magnetic field in the upper chromosphere and
  transition region of the Sun. The CLASP proposal has been accepted by
  NASA in 2012, and the flight is planned in 2015.

Title: Large aperture solar optical telescope and instruments for
    the SOLAR-C mission
Authors: Suematsu, Y.; Katsukawa, Y.; Hara, H.; Kano, R.; Shimizu,
   T.; Ichimoto, K.
Bibcode: 2014SPIE.9143E..1PS
Altcode:
  A large aperture solar optical telescope and its instruments
  for the SOLAR-C mission are under study to provide the critical
  physical parameters in the lower solar atmosphere and to resolve the
  mechanism of magnetic dynamic events happening there and in the upper
  atmosphere as well. For the precise magnetic field measurements and
  high angular resolution in wide wavelength region, covering FOV of 3
  arcmin x3 arcmin, an entrance aperture of 1.4 m Gregorian telescope is
  proposed. Filtergraphs are designed to realize high resolution imaging
  and pseudo 2D spectro-polarimetry in several magnetic sensitive lines of
  both photosphere and chromosphere. A full stokes polarimetry is carried
  out at three magnetic sensitive lines with a four-slit spectrograph
  of 2D image scanning mechanism. We present a progress in optical and
  structural design of SOLAR-C large aperture optical telescope and its
  observing instruments which fulfill science requirements.

Title: Polarization properties of a birefringent fiber optic image
    slicer for diffraction-limited dual-beam spectropolarimetry
Authors: Schad, Thomas; Lin, Haosheng; Ichimoto, Kiyoshi; Katsukawa,
   Yukio
Bibcode: 2014SPIE.9147E..6ES
Altcode:
  The birefringent fiber optic image slicer design, or BiFOIS,
  adapts integral field spectroscopy methods to the special needs of
  high-sensitivity, spatially-resolved spectropolarimetry. In solar
  astronomy these methods are of particular importance, as dynamic
  magnetism lies at the heart of various multi-scaled phenomena in the
  solar atmosphere. While integral field units (IFU) based on fiber
  optics have been in continual development for some time, standard
  stock multimode fibers do not typically preserve polarization. The
  importance of a birefringent fiber optic IFU design stems from the
  need for dual-beam spatio-temporal polarimetric modulation to correct
  for spurious polarization signals induced either by platform jitter or
  atmospheric seeing. Here we characterize the polarization response of a
  second generation BiFOIS IFU designed for solar spectropolarimetry. The
  unit provides 60 × 64 spatial imaging pixels in a densely-packed,
  high filling factor configuration. Particular attention is placed on
  the spatial uniformity of the IFU polarization response. Calibrated
  first-light solar observations are also presented to demonstrate the
  performance of the device in a real application.

Title: Current progress of optical alignment procedure of CLASP's
    Lyman-alpha polarimetry instrument
Authors: Giono, G.; Ishikawa, R.; Katsukawa, Y.; Bando, T.; Kano, R.;
   Suematsu, Y.; Narukage, N.; Sakao, Taro; Kobayashi, K.; Auchère, F.
Bibcode: 2014SPIE.9144E..3EG
Altcode:
  The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a
  sounding-rocket instrument currently under development at the
  National Astronomical Observatory of Japan (NAOJ) as a part of an
  international collaboration. CLASP's optics are composed of a Cassegrain
  telescope and a spectro-polarimeter which are designed to achieve an
  unprecedentedly accurate polarization measurement of the Ly-α line
  at 121.6nm emitted from the solar upper-chromosphere and transition
  region. CLASP's first flight is scheduled for August 2015. Reaching
  such accuracy requires a careful alignment of the optical elements
  to optimize the image quality at 121.6 nm. However Ly-α is absorbed
  by air and therefore the optics alignment has to be done under vacuum
  condition which makes any experiment difficult. To bypass this issue,
  we proposed to align the telescope and the spectrograph separately
  in visible light. Hence we present our alignment procedure for both
  telescope and spectro-polarimeter. We will explain details about the
  telescope preliminary alignment before mirrors coating, which was done
  in April 2014, present the telescope combined optical performance
  and compare them to CLASP tolerance. Then we will present details
  about an experiment designed to confirm our alignment procedure for
  the CLASP spectro-polarimeter. We will discuss the resulting image
  quality achieved during this experiment and the lessons learned.

Title: Reconnection in the solar magnetic fields beyond HINODE
Authors: Katsukawa, Yukio
Bibcode: 2014cosp...40E1427K
Altcode:
  HINODE has revealed that magnetic reconnection plays an important
  role in energy conversion process not only in the corona but
  also in the chromosphere which is a relatively dense and plasma
  beta = 1 atmospheric layer located between the photosphere and the
  corona. Lots of small-scale jets are identified in the chromosphere
  and they are expected to be driven not only by Lorentz force, but
  also through strong influence of gas pressures and generation of MHD
  waves. HINODE has indicated pervasive MHD waves in the chromosphere,
  but there is little observations showing how such waves are generated
  by the reconnection and how the waves drive flows and heating. Their
  possible influence to the coronal heating is also an important
  problem. For tackling them, our strong demand is to obtain detailed
  diagnostic capability of plasma parameters as well as magnetic fields
  by spectroscopic and spectro-polarimetric measurements with high
  spatial resolution. IRIS (Interface Region Imaging Spectrograph)
  has just started its observations since 2013, and is now providing
  spectroscopic data of the chromosphere with unprecedented spatial
  and temporal resolution. For remotely sensing magnetic fields in the
  solar atmosphere, precise measurements of polarization signals are
  highly demanded which is going to be attempted in a sounding-rocket
  experiment CLASP (Chromospheric Lyman-Alpha SpectroPolarimeter) and
  the next solar physics satellite SOLAR-C.

Title: Chromospheric Lyman-alpha spectro-polarimeter (CLASP)
Authors: Kano, Ryouhei; Katsukawa, Yukio; Kubo, Masahito; Auchere,
   Frederic; Ishikawa, Ryohko; Kobayashi, Ken; Narukage, Noriyuki;
   Trujillo Bueno, Javier; Bando, Takamasa; Ishikawa, Shin-nosuke
Bibcode: 2014cosp...40E1383K
Altcode:
  In the solar chromosphere, magneto-hydrodynamic waves and super-sonic
  jets ubiquitously happen as revealed by the Japanese solar satellite
  Hinode. Now, we understand that the solar chromosphere is not a simple
  intermediate layer smoothly connecting the photosphere and corona,
  but a site where those dynamics may play an important role in the
  chromospheric and coronal heating. Such discoveries imply that the
  next frontier in solar physics lies in simultaneous observations
  between the dynamics and magnetic structures in the chromosphere and
  transition region, where the gas-dominant photosphere changes to the
  magnetic-dominant corona. Therefore, we promote the Chromospheric
  Lyman-Alpha SpectroPolarimeter (CLASP), which is a NASA's sounding
  rocket experiment scheduled in 2015 for aiming to infer the magnetic
  field information in the solar chromosphere and transition region. CLASP
  makes precise measurement (0.1%) of the polarization profile of the
  Lyman-alpha line, and aims to make the first ever measurement of the
  Hanle effect polarization caused by magnetic fields in the upper solar
  atmosphere. It is also a pathfinder to establish a new measurement
  tool for chromospheric and transition-region magnetic fields, and to
  make progress on chromospheric studies in future missions.

Title: Coronal rain observed with IRIS
Authors: Antolin, Patrick; Katsukawa, Yukio; De Pontieu, Bart; Kleint,
   Lucia; Pereira, Tiago
Bibcode: 2014cosp...40E.105A
Altcode:
  New IRIS observations in upper chromospheric and TR lines show abundance
  of coronal rain in active regions. The wide range of spectral lines in
  which it is observed together with co-observations in cool chromospheric
  lines with SOT and SST show clearly that coronal rain has a broad
  multi-thermal character. This picture agrees well with the thermal
  instability scenario in which the plasma cools down catastrophically
  from coronal temperatures. A statistical analysis of the line widths
  in the rain provides estimates of the non-thermal line broadening and
  temperature. Mainly, we find Gaussian-like distributions of non-thermal
  line broadening between 0 and 17 km/s with a peak at 7 km/s and a small
  upper tail spanning up to 25 km/s. We also report on short-lived heating
  events in umbrae and penumbrae at the end of thermally unstable coronal
  loops. Bursts of high redshifts up to 200 km/s in TR lines are found,
  accompanied by milder blue shifts. The bright dots sometimes display
  coherent structure into a "string of pearls" with striking similarity
  to flare ribbons, suggesting a strong heating correlation between the
  loops. We discuss these results within the coronal rain scenario.

Title: Flux emergence in the solar internetwork and its contribution
    to the network
Authors: Gosic, Milan; Katsukawa, Yukio; Orozco Suarez, David; Bellot
   Rubio, L. R.
Bibcode: 2014cosp...40E1055G
Altcode:
  Network and internetwork magnetic fields are believed to play a
  crucial role in the energy budget of the solar atmosphere. Therefore,
  it is essential to understand how they are maintained on the
  solar surface. Using high resolution Hinode/NFI magnetograms at
  disk center, we automatically follow quiet Sun magnetic elements
  from their appearance to disappearance. From up to 40 hours of
  continuous measurements, we derive the flux emergence rate in the
  solar internetwork to be around 40 Mx cm(-2) day(-1) . We show
  that internetwork fields appearing in the interior of individual
  supergranular cells contribute flux to the surrounding network at
  a rate of 2×10(19) Mx h(-1) . In only 10-20 hours, internetwork
  elements can transfer as much flux as resides in network features,
  establishing them as the most important source of flux for the network
  and the quiet Sun flux budget.

Title: UV spectropolarimeter design for precise polarization
    measurement and its application to the CLASP for exploration of
    magnetic fields in solar atmosphere
Authors: Narukage, Noriyuki; Katsukawa, Yukio; Hara, Hirohisa; Kubo,
   Masahito; Auchere, Frederic; Ishikawa, Ryohko; Kano, Ryouhei; Bando,
   Takamasa; Ishikawa, Shin-nosuke; Suematsu, Yoshinori; Tsuneta, Saku
Bibcode: 2014cosp...40E2232N
Altcode:
  In order to measure the magnetic field in the region where the
  hot plasma from 10 (4) K to 10 (6) K is occupied, e.g., for solar
  atmosphere, the polarimetric measurements in ultra violet (UV)
  with 0.1% accuracy are required. In this paper, we propose a new
  UV spectropolarimeter design with 0.1% sensitivity in polarization
  measurement. This spectropolarimeter has two devices for the 0.1%
  accuracy. First, all optical components except the waveplate are the
  reflective type ones that can be equipped with the high reflectivity
  coating for the high throughput. Secondly, it equips the optically
  symmetric dual channels to measure the orthogonal linear polarization
  state simultaneously, using a concave diffraction grating as both the
  spectral dispersion element and the beam splitter. These two devices
  make the spurious polarizations caused by the photon noise, by the
  intensity variation of the observation target, and, by the instrument
  itself, enough small to achieve the 0.1% accuracy in polarization
  measurement. The spectropolarimeter thus designed is currently under
  fabrication for the sounding rocket project of Chromospheric Lyman-Alpha
  SpectroPolarimeter (CLASP) that aims at the direct measurement of the
  magnetic fields in solar atmosphere with Lyman-alpha line (121.6 nm)
  for the first time.

Title: Spectral Signatures of Penumbral Transients
Authors: Reardon, K.; Tritschler, A.; Katsukawa, Y.
Bibcode: 2013ApJ...779..143R
Altcode:
  In this work we investigate the properties of penumbral transients
  observed in the upper photospheric and chromospheric region above a
  sunspot penumbra using two-dimensional spectroscopic observations
  of the Ca II 854.21 nm line with a 5 s cadence. In our 30 minutes
  of observations, we identify several penumbral-micro jets (PMJs)
  with cotemporal observations from Dunn Solar Telescope/IBIS and
  Hinode/SOT. We find that the line profiles of these PMJ events
  show emission in the two wings of the line (±0.05 nm), but
  little modification of the line core. These are reminiscent of
  the line profiles of Ellerman bombs observed in plage and network
  regions. Furthermore, we find evidence that some PMJ events have a
  precursor phase starting 1 minute prior to the main brightening that
  might indicate initial heating of the plasma prior to an acoustic or
  bow shock event. With the IBIS data, we also find several other types
  of transient brightenings with timescales of less than 1 minute that
  are not clearly seen in the Hinode/SOT data. The spectral profiles and
  other characteristics of these events are significantly different from
  those of PMJs. The different appearances of all these transients are
  an indicator of the general complexity of the chromospheric magnetic
  field and underscore the highly dynamic behavior above sunspots. It
  also highlights the care that is needed in interpreting broadband
  filter images of chromospheric lines, which may conceal very different
  spectral profiles, and the underlying physical mechanisms at work.

Title: FISS Observations of Vertical Motion of Plasma in Tiny Pores
Authors: Cho, K. -S.; Bong, S. -C.; Chae, J.; Kim, Y. -H.; Park,
   Y. -D.; Katsukawa, Y.
Bibcode: 2013SoPh..288...23C
Altcode:
  Pores can be exploited for the understanding of the interaction
  between small-scale vertical magnetic field and the surrounding
  convective motions as well as the transport of mechanical energy into
  the chromosphere along the magnetic field. For better understanding of
  the physics of pores, we investigate tiny pores in a new emerging
  active region (AR11117) that were observed on 26 October 2010
  by the Solar Optical Telescope (SOT) on board Hinode and the Fast
  Imaging Solar Spectrograph (FISS) of the 1.6 meter New Solar Telescope
  (NST). The pores are compared with nearby small magnetic concentrations
  (SMCs), which have similar magnetic flux as the pores but do not
  appear dark. Magnetic flux density and Doppler velocities in the
  photosphere are estimated by applying the center-of-gravity method to
  the Hinode/Spectro-Polarimeter data. The line-of-sight motions in the
  lower chromosphere are determined by applying the bisector method to
  the wings of the Hα and the Ca II 8542 Å line simultaneously taken
  by the FISS. The coordinated observation reveals that the pores are
  filled with plasma which moves down slowly and are surrounded by
  stronger downflow in the photosphere. In the lower chromosphere, we
  found that the plasma flows upwards inside the pores while the plasma
  in the SMCs is always moving down. Our inspection of the Ca II 8542 Å
  line from the wing to the core shows that the upflow in the pores slows
  down with height and turns into downflow in the upper chromosphere
  while the downflow in the SMCs gains its speed. Our results are in
  agreement with the numerical studies which suggest that rapid cooling
  of the interior of the pores drives a strong downflow, which collides
  with the dense lower layer below and rebounds into an upflow.

Title: Chromospheric Lyman Alpha SpectroPolarimeter: CLASP
Authors: Kobayashi, Ken; Kano, R.; Trujillo Bueno, J.; Winebarger,
   A. R.; Cirtain, J. W.; Bando, T.; De Pontieu, B.; Ishikawa, R.;
   Katsukawa, Y.; Kubo, M.; Narukage, N.; Sakao, T.; Tsuneta, S.;
   Auchère, F.; Asensio Ramos, A.; Belluzzi, L.; Carlsson, M.; Casini,
   R.; Hara, H.; Ichimoto, K.; Manso Sainz, R.; Shimizu, T.; Stepan,
   J.; Suematsu, Y.; Holloway, T.
Bibcode: 2013SPD....44..142K
Altcode:
  The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a VUV
  spectropolarimeter optimized for measuring the linear polarization of
  the Lyman-alpha line (121.6 nm). The Lyman-alpha line is predicted to
  show linear polarization caused by atomic scattering in the chromosphere
  and modified by the magnetic field through the Hanle effect. The
  Hanle effect is sensitive to weaker magnetic fields than Zeeman
  effect, and is not canceled by opposing fields, making it sensitive
  to tangled or unresolved magnetic field structures. These factors make
  the Hanle effect a valuable tool for probing the magnetic field in the
  chromosphere above the quiet sun. To meet this goal, CLASP is designed
  to measure linear polarization with 0.1% polarization sensitivity
  at 0.01 nm spectral resolution and 10" spatial resolution. CLASP is
  scheduled to be launched in 2015.

Title: The Hinode Spectro-Polarimeter
Authors: Lites, B. W.; Akin, D. L.; Card, G.; Cruz, T.; Duncan, D. W.;
   Edwards, C. G.; Elmore, D. F.; Hoffmann, C.; Katsukawa, Y.; Katz, N.;
   Kubo, M.; Ichimoto, K.; Shimizu, T.; Shine, R. A.; Streander, K. V.;
   Suematsu, A.; Tarbell, T. D.; Title, A. M.; Tsuneta, S.
Bibcode: 2013SoPh..283..579L
Altcode:
  The joint Japan/US/UK Hinode mission includes the first large-aperture
  visible-light solar telescope flown in space. One component of the
  Focal Plane Package of that telescope is a precision spectro-polarimeter
  designed to measure full Stokes spectra with the intent of using those
  spectra to infer the magnetic-field vector at high precision in the
  solar photosphere. This article describes the characteristics of the
  flight hardware of the HinodeSpectro-Polarimeter, and summarizes its
  in-flight performance.

Title: Next space solar observatory SOLAR-C: mission instruments
    and science objectives
Authors: Katsukawa, Y.; Watanabe, T.; Hara, H.; Ichimoto, K.; Kubo,
   M.; Kusano, K.; Sakao, T.; Shimizu, T.; Suematsu, Y.; Tsuneta, S.
Bibcode: 2012IAUSS...6E.207K
Altcode:
  SOLAR-C, the fourth space solar mission in Japan, is under study with a
  launch target of fiscal year 2018. A key concept of the mission is to
  view the photosphere, chromosphere, and corona as one system coupled
  by magnetic fields along with resolving the size scale of fundamental
  physical processes connecting these atmospheric layers. It is especially
  important to study magnetic structure in the chromosphere as an
  interface layer between the photosphere and the corona. The SOLAR-C
  satellite is equipped with three telescopes, the Solar UV-Visible-IR
  Telescope (SUVIT), the EUV/FUV High Throughput Spectroscopic Telescope
  (EUVS/LEMUR), and the X-ray Imaging Telescope (XIT). Observations
  with SUVIT of photospheric and chromospheric magnetic fields make it
  possible to infer three dimensional magnetic structure extending from
  the photosphere to the chromosphere and corona.This helps to identify
  magnetic structures causing magnetic reconnection, and clarify how
  waves are propagated, reflected, and dissipated. Phenomena indicative
  of or byproducts of magnetic reconnection, such as flows and shocks,
  are to be captured by SUVIT and by spectroscopic observations using
  EUVS/LEMUR, while XIT observes rapid changes in temperature distribution
  of plasma heated by shock waves.

Title: Instrument Design of the Large Aperture Solar UV Visible and
    IR Observing Telescope (SUVIT) for the SOLAR-C Mission
Authors: Suematsu, Y.; Katsukawa, Y.; Shimizu, T.; Ichimoto, K.;
   Takeyama, N.
Bibcode: 2012ASPC..463..439S
Altcode:
  We present an instrumental design of one major solar observation payload
  planned for the SOLAR-C mission: the Solar Ultra-violet Visible and
  near IR observing Telescope (SUVIT). The SUVIT is designed to provide
  high-angular-resolution investigation of the lower solar atmosphere,
  from the photosphere to the uppermost chromosphere, with enhanced
  spectroscopic and spectro-polarimetric capability in wide wavelength
  regions from 280 nm (Mg II h&amp;k lines) to 1100 nm (He I 1083 nm
  line) with 1.5 m class aperture and filtergraphic and spectrographic
  instruments.

Title: Science and Instrument Design of 1.5-m Aperture Solar Optical
    Telescope for the SOLAR-C Mission
Authors: Suematsu, Y.; Katsukawa, Y.; Ichimoto, K.; Shimizu, T.
Bibcode: 2012IAUSS...6E.208S
Altcode:
  We present science cases and a design of one of major instruments for
  SOLAR-C mission; 1.5-m-class aperture solar ultra-violet visible and
  near IR observing Telescope (SUVIT). The SOLAR-C mission aims at fully
  understanding dynamism and magnetic nature of the solar atmosphere by
  observing small-scale plasma processes and structures. The SUVIT is
  designed to provide high-angular-resolution investigation of lower
  atmosphere from the photosphere to the uppermost chromosphere with
  enhanced spectroscopic and spectro-polarimetric capability covering
  a wide wavelength region from 280 nm (Mg II h&amp;k) to 1100 nm (He
  I 1083 nm), using focal plane instruments: wide-band and narrow-band
  filtergraphs and a spectrograph for high-precision spectro-polarimetry
  in the solar photospheric and chromospheric lines. We will discuss
  about instrument design to realize the science cases.

Title: Requirements for the Analysis of Quiet-Sun Internetwork
    Magnetic Elements with EST and ATST
Authors: Orozco Suárez, D.; Bellot Rubio, L. R.; Katsukawa, Y.
Bibcode: 2012ASPC..463...57O
Altcode: 2012arXiv1203.2185O
  The quiet-Sun internetwork is permeated by weak and highly inclined
  magnetic fields whose physical properties, dynamics, and magnetic
  interactions are not fully understood. High spatial resolution
  magnetograms show them as discrete magnetic elements that appear/emerge
  and disappear/cancel continuously over the quiet Sun surface. The
  4-m European Solar Telescope (EST) and the Advanced Technology
  Solar Telescope (ATST) will obtain two-dimensional, high cadence,
  high precision polarimetric measurements at the diffraction limit
  (30 km). Here, we compile the basic requirements for the observation
  of internetwork fields with EST and ATST (field of view, cadence,
  instrument configuration, etc.). More specifically, we concentrate
  on the field-of-view requirements. To set them we analyze the proper
  motion of internetwork magnetic elements across the solar surface. We
  use 13 hours of magnetograms taken with the Hinode satellite to
  identify and track thousands of internetwork magnetic element in an
  isolated supergranular cell. We calculate the velocity components of
  each element and the mean distance they travel. The results show that,
  on average, magnetic elements in the interior of supergranular cells
  move toward the network. The radial velocity is observed to depend on
  the distance to the center of the supergranule. Internetwork magnetic
  elements travel 4″ on average. These results suggest that ATST and
  EST should cover, at least, one supergranular cell to obtain a complete
  picture of the quiet Sun internetwork.

Title: The Connection between Internetwork Magnetic Elements and
    Supergranular Flows
Authors: Orozco Suárez, D.; Katsukawa, Y.; Bellot Rubio, L. R.
Bibcode: 2012ApJ...758L..38O
Altcode:
  The advection of internetwork magnetic elements by supergranular
  convective flows is investigated using high spatial resolution, high
  cadence, and high signal-to-noise ratio Na I D1 magnetograms obtained
  with the Hinode satellite. The observations show that magnetic elements
  appear everywhere across the quiet Sun surface. We calculate the proper
  motion of these magnetic elements with the aid of a feature tracking
  algorithm. The results indicate that magnetic elements appearing in
  the interior of supergranules tend to drift toward the supergranular
  boundaries with a non-constant velocity. The azimuthally averaged
  radial velocities of the magnetic elements and of the supergranular
  flow, calculated from a local correlation tracking technique applied
  to Dopplergrams, are very similar. This suggests that, in the long
  term, surface magnetic elements are advected by supergranular flows,
  although on short timescales their very chaotic motions are driven
  mostly by granular flows and other processes.

Title: Power Spectra of Velocities and Magnetic Fields on the Solar
    Surface and their Dependence on the Unsigned Magnetic Flux Density
Authors: Katsukawa, Y.; Orozco Suárez, D.
Bibcode: 2012ApJ...758..139K
Altcode: 2012arXiv1209.0548K
  We have performed power spectral analysis of surface temperatures,
  velocities, and magnetic fields, using spectropolarimetric data taken
  with the Hinode Solar Optical Telescope. When we make power spectra in
  a field of view covering the supergranular scale, kinetic and thermal
  power spectra have a prominent peak at the granular scale while the
  magnetic power spectra have a broadly distributed power over various
  spatial scales with weak peaks at both the granular and supergranular
  scales. To study the power spectra separately in internetwork and
  network regions, power spectra are derived in small subregions extracted
  from the field of view. We examine slopes of the power spectra using
  power-law indices, and compare them with the unsigned magnetic flux
  density averaged in the subregions. The thermal and kinetic spectra
  are steeper than the magnetic ones at the subgranular scale in the
  internetwork regions, and the power-law indices differ by about 2. The
  power-law indices of the magnetic power spectra are close to or smaller
  than -1 at that scale, which suggests the total magnetic energy mainly
  comes from either the granular scale magnetic structures or both the
  granular scale and smaller ones contributing evenly. The slopes of the
  thermal and kinetic power spectra become less steep with increasing
  unsigned flux density in the network regions. The power-law indices
  of all the thermal, kinetic, and magnetic power spectra become similar
  when the unsigned flux density is larger than 200 Mx cm<SUP>-2</SUP>.

Title: Design of large aperture solar optical telescope for the
    SOLAR-C mission
Authors: Suematsu, Y.; Katsukawa, Y.; Hara, H.; Shimizu, T.;
   Ichimoto, K.
Bibcode: 2012SPIE.8442E..25S
Altcode:
  A large aperture optical telescope is planned for the next Japanese
  solar mission SOLAR-C as one of major three observing instruments. The
  optical telescope is designed to provide high-angular-resolution
  investigation of lower atmosphere from the photosphere to the uppermost
  chromosphere with enhanced spectroscopic and spectro-polarimetric
  capability covering a wide wavelength region from 280 nm to 1100
  nm. The opto-mechanical and -thermal performance of the telescope is
  crucial to attain high-quality solar observations and we present a
  study of optical and structural design of the large aperture space
  solar telescope, together with conceptual design of its accompanying
  focal plane instruments: wide-band and narrow-band filtergraphs and
  a spectro-polarimeter for high spatial and temporal observations in
  the solar photospheric and chromospheric lines useful for sounding
  physical condition of dynamical phenomena.

Title: Chromospheric Lyman-alpha spectro-polarimeter (CLASP)
Authors: Kano, Ryouhei; Bando, Takamasa; Narukage, Noriyuki; Ishikawa,
   Ryoko; Tsuneta, Saku; Katsukawa, Yukio; Kubo, Masahito; Ishikawa,
   Shin-nosuke; Hara, Hirohisa; Shimizu, Toshifumi; Suematsu, Yoshinori;
   Ichimoto, Kiyoshi; Sakao, Taro; Goto, Motoshi; Kato, Yoshiaki; Imada,
   Shinsuke; Kobayashi, Ken; Holloway, Todd; Winebarger, Amy; Cirtain,
   Jonathan; De Pontieu, Bart; Casini, Roberto; Trujillo Bueno, Javier;
   Štepán, Jiří; Manso Sainz, Rafael; Belluzzi, Luca; Asensio Ramos,
   Andres; Auchère, Frédéric; Carlsson, Mats
Bibcode: 2012SPIE.8443E..4FK
Altcode:
  One of the biggest challenges in heliophysics is to decipher the
  magnetic structure of the solar chromosphere. The importance of
  measuring the chromospheric magnetic field is due to both the key role
  the chromosphere plays in energizing and structuring the outer solar
  atmosphere and the inability of extrapolation of photospheric fields to
  adequately describe this key boundary region. Over the last few years,
  significant progress has been made in the spectral line formation
  of UV lines as well as the MHD modeling of the solar atmosphere. It
  is found that the Hanle effect in the Lyman-alpha line (121.567 nm)
  is a most promising diagnostic tool for weaker magnetic fields in
  the chromosphere and transition region. Based on this groundbreaking
  research, we propose the Chromospheric Lyman-Alpha Spectro-Polarimeter
  (CLASP) to NASA as a sounding rocket experiment, for making the first
  measurement of the linear polarization produced by scattering processes
  and the Hanle effect in the Lyman-alpha line (121.567 nm), and making
  the first exploration of the magnetic field in the upper chromosphere
  and transition region of the Sun. The CLASP instrument consists
  of a Cassegrain telescope, a rotating 1/2-wave plate, a dual-beam
  spectrograph assembly with a grating working as a beam splitter, and
  an identical pair of reflective polarization analyzers each equipped
  with a CCD camera. We propose to launch CLASP in December 2014.

Title: Persistent Circulating Motion in a Sunspot Umbra
Authors: Katsukawa, Y.; Kitai, R.; Watanabe, H.
Bibcode: 2012ASPC..454..213K
Altcode:
  We studied temporal evolution of flow patterns inside an umbra
  using the local correlation tracking algorithm applied to long-term
  filtergram data of a matured sunspot taken with the Hinode Solar
  Optical Telescope. We found not only inward migration of umbral dots
  in a peripheral region of the umbra but also a circulating motion in
  a central region of the umbra. The circulating motion was persistently
  observed for at least 3 days. The observation suggests that there are
  magnetic and flow structures below a sunspot maintaining the motion
  of umbral dots.

Title: The SOLAR-C Mission: Plan B Payload Concept
Authors: Shimizu, T.; Sakao, T.; Katsukawa, Y.; Group, J. S. W.
Bibcode: 2012ASPC..454..449S
Altcode:
  The telescope concepts for the SOLAR-C Plan B mission as of the time of
  the Hinode-3 meeting were briefly presented for having comments from
  the international solar physics community. The telescope candidates
  are 1) near IR-visible-UV telescope with 1.5m aperture and enhanced
  spectro-polarimetric capability, 2) UV/EUV high throughput spectrometer,
  and 3) next generation X-ray telescope.

Title: Evolution of internetwork magnetic fields inside supergranular
    cells
Authors: Gosic, Milan; Katsukawa, Yukio; Bellot Rubio, Luis; Orozco
   Suarez, David
Bibcode: 2012cosp...39..657G
Altcode: 2012cosp.meet..657G
  To understand the formation of small-scale magnetic fields in the quiet
  Sun and their contribution to the solar activity, it is essential to
  investigate the properties of internetwork magnetic fields. Using
  Hinode/NFI magnetograms of very high sensitivity (7 Mx/cm^{2}),
  spatial resolution (0.16 arcsec/pixel), and cadence (90 s), we
  follow the evolution of magnetic fields inside of a supergranular
  cell located at disk center. In 5 hours of continuous measurements
  covering an area of 20.8 × 23.2 arcsec^{2}, we manually track 2415
  magnetic elements from appearance to disappearance and derive their
  physical properties. The average values of the magnetic flux, effective
  diameter, lifetime, and horizontal velocity are 3 × 10^{17} Mx, 0.5 Mm,
  17 min, and 2 km/s, respectively. We also investigate how the physical
  parameters of the individual elements vary as a function of time,
  flux, and spatial position. Using this unique data set, we determine
  with unprecedented accuracy the flux emergence and disappearance rate
  in the solar internetwork.

Title: The Chromospheric Lyman-Alpha SpectroPolarimeter: CLASP
Authors: Kobayashi, K.; Kano, R.; Trujillo-Bueno, J.; Asensio Ramos,
   A.; Bando, T.; Belluzzi, L.; Carlsson, M.; De Pontieu, R. C. B.; Hara,
   H.; Ichimoto, K.; Ishikawa, R.; Katsukawa, Y.; Kubo, M.; Manso Sainz,
   R.; Narukage, N.; Sakao, T.; Stepan, J.; Suematsu, Y.; Tsuneta, S.;
   Watanabe, H.; Winebarger, A.
Bibcode: 2012ASPC..456..233K
Altcode:
  The magnetic field plays a crucial role in the chromosphere and the
  transition region, and our poor empirical knowledge of the magnetic
  field in the upper chromosphere and transition region is a major
  impediment to advancing the understanding of the solar atmosphere. The
  Hanle effect promises to be a valuable alternative to Zeeman effect
  as a method of measuring the magnetic field in the chromosphere and
  transition region; it is sensitive to weaker magnetic fields, and
  also sensitive to tangled, unresolved field structures. <P />CLASP
  is a sounding rocket experiment that aims to observe the Hanle effect
  polarization of the Lyman α (1215.67Å) line in the solar chromosphere
  and transition region, and prove the usefulness of this technique in
  placing constraints on the magnetic field strength and orientation
  in the low plasma-β region of the solar atmosphere. The Ly-α line
  has been chosen because it is a chromospheric/transition-region line,
  and because the Hanle effect polarization of this line is predicted to
  be sensitive to 10-250 Gauss, encompassing the range of interest. The
  CLASP instrument is designed to measure linear polarization in the
  Ly-α line with a polarization sensitivity of 0.1%. The instrument is
  currently funded for development. The optical design of the instrument
  has been finalized, and an extensive series of component-level tests
  are underway to validate the design.

Title: On the Distribution of Quiet-Sun Magnetic Fields at Different
    Heliocentric Angles
Authors: Orozco Suárez, D.; Katsukawa, Y.
Bibcode: 2012ApJ...746..182O
Altcode:
  This paper presents results from the analysis of high signal-to-noise
  ratio spectropolarimetric data taken at four heliocentric angles in
  quiet-Sun internetwork regions with the Hinode satellite. First, we
  find that the total circular and total linear polarization signals vary
  with heliocentric angle, at least for fields with large polarization
  signals. We also report changes on the Stokes V amplitude asymmetry
  histograms with viewing angle for fields weaker than 200 G. Then,
  we subject the data to a Milne-Eddington inversion and analyze
  the variation of the field vector probability density functions
  with heliocentric angle. Weak, highly inclined fields permeate
  the internetwork at all heliocentric distances. For fields weaker
  than 200 G, the distributions of field inclinations peak at 90°
  and do not vary with viewing angle. The inclination distributions
  change for fields stronger than 200 G. We argue that the shape of
  the inclination distribution for weak fields partly results from the
  presence of coherent, loop-like magnetic features at all heliocentric
  distances and not from tangled fields within the field of view. We also
  find that the average magnetic field strength is about 180 G (for 75%
  of the pixels) and is constant with heliocentric angle. The average
  vertical and horizontal magnetic field components are 70 and 150 G. The
  latter (former) is slightly greater (smaller) near the limb. Finally,
  the ratio between the horizontal and vertical components of the fields
  ranges from ~1 for strong fields to ~3.5 for weak fields, suggesting
  that the magnetic field vector is not isotropically distributed within
  the field of view.

Title: The Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP)j
Authors: Kobayashi, K.; Tsuneta, S.; Trujillo Bueno, J.; Bando, T.;
   Belluzzi, L.; Casini, R.; Carlsson, M.; Cirtain, J. W.; De Pontieu,
   B.; Hara, H.; Ichimoto, K.; Ishikawa, R.; Kano, R.; Katsukawa, Y.;
   Kim, T.; Kubo, M.; Manso Sainz, R.; Narukage, N.; Asensio Ramos,
   A.; Robinson, B.; Sakao, T.; Shimizu, T.; Stepan, J.; Suematsu, Y.;
   Watanabe, H.; West, E.; Winebarger, A. R.
Bibcode: 2011AGUFM.P14C..05K
Altcode:
  We present an overview of the Chromospheric Lyman-Alpha
  SpectroPolarimeter (CLASP) program. CLASP is a proposed sounding rocket
  experiment currently under development as collaboration between Japan,
  USA and Spain. The aim is to achieve the first measurement of magnetic
  field in the upper chromosphere and transition region of the Sun
  through the detection and measurement of Hanle effect polarization
  of the Lyman alpha line. The Hanle effect (i.e. the magnetic field
  induced modification of the linear polarization due to scattering
  processes in spectral lines) is believed to be a powerful tool for
  measuring the magnetic field in the upper chromosphere, as it is more
  sensitive to weaker magnetic fields than the Zeeman effect, and also
  sensitive to magnetic fields tangled at spatial scales too small to be
  resolved. The Lyman-alpha (121.567 nm) line has been chosen because
  it is a chromospheric/transition-region line, and because the Hanle
  effect polarization of the Lyman-alpha line is predicted to be sensitive
  to 10-250 Gauss, encompassing the range of interest. Hanle effect is
  predicted to be observable as linear polarization or depolarization,
  depending on the geometry, with a fractional polarization amplitude
  varying between 0.1% and 1% depending on the strength and orientation of
  the magnetic field. This quantification of the chromospheric magnetic
  field requires a highly sensitive polarization measurement. The
  CLASP instrument consists of a large aperture (287 mm) Cassegrain
  telescope mated to a polarizing beamsplitter and a matched pair
  of grating spectrographs. The polarizing beamsplitter consists
  of a continuously rotating waveplate and a linear beamsplitter,
  allowing simultaneous measurement of orthogonal polarizations and
  in-flight self-calibration. Development of the instrument is underway,
  and prototypes of all optical components have been tested using a
  synchrotron beamline. The experiment is proposed for flight in 2014.

Title: Magnetic Field Diagnostics with the HINODE Spectro-Polarimeter
Authors: Katsukawa, Y.; Hinode Sot Team
Bibcode: 2011AGUFMSH33C..01K
Altcode:
  After HINODE started its observations in 2006, the Spectro-Polarimeter
  (SP) aboard Hinode has provided unique data for studies of photospheric
  magnetic fields. Advantages of the HINODE SP is that we can get
  full polarimetric and spectroscopic information on Zeeman-sensitive
  photospheric lines as well as stable image quality whose angular
  resolution is 0.3 arcsec. It allows us to carry out detailed studies on
  magentic and flow structures of sunspot fine structures (e.g. umbral
  dots, light bridges, and penumbral filaments) and properties of the
  quiet Sun magnetic fields, which has provided insights on how magnetic
  flux interacts with convective flows in the photosphere. Vector field
  maps generated through a Stokes inversion technique are accurate
  enough to track development of magnetic shear toward the onset of a
  flare, and are also useful to carry out the nonlinear force-free field
  (NLFFF) extrapolation. The weakness of the HINODE SP observations is
  a limited field-of-view and temporal coverage because of the scanning
  instrument. This is why complementary observations with SDO/HMI and
  SOLIS are important in the current increasing solar activity.

Title: Focal plane instrument for the Solar UV-Vis-IR Telescope
    aboard SOLAR-C
Authors: Katsukawa, Yukio; Suematsu, Yoshinori; Shimizu, Toshifumi;
   Ichimoto, Kiyoshi; Takeyama, Norihide
Bibcode: 2011SPIE.8148E..0EK
Altcode: 2011SPIE.8148E..13K
  It is presented the conceptual design of a focal plane instrument for
  the Solar UV-Vis-IR Telescope (SUVIT) aboard the next Japanese solar
  mission SOLAR-C. A primary purpose of the telescope is to achieve
  precise as well as high resolution spectroscopic and polarimetric
  measurements of the solar chromosphere with a big aperture of 1.5 m,
  which is expected to make a significant progress in understanding basic
  MHD processes in the solar atmosphere. The focal plane instrument
  consists of two packages: A filtergraph package is to get not only
  monochromatic images but also Dopplergrams and magnetograms using a
  tunable narrow-band filter and interference filters. A spectrograph
  package is to perform accurate spectro-polarimetric observations for
  measuring chromospheric magnetic fields, and is employing a Littrow-type
  spectrograph. The most challenging aspect in the instrument design is
  wide wavelength coverage from 280 nm to 1.1 μm to observe multiple
  chromospheric lines, which is to be realized with a lens unit including
  fluoride glasses. A high-speed camera for correlation tracking of
  granular motion is also implemented in one of the packages for an
  image stabilization system, which is essential to achieve high spatial
  resolution and high polarimetric accuracy.

Title: Overview of Chromospheric Lyman-Alpha SpectroPolarimeter
    (CLASP)
Authors: Narukage, Noriyuki; Tsuneta, Saku; Bando, Takamasa; Kano,
   Ryouhei; Kubo, Masahito; Ishikawa, Ryoko; Hara, Hirohisa; Suematsu,
   Yoshinori; Katsukawa, Yukio; Watanabe, Hiroko; Ichimoto, Kiyoshi;
   Sakao, Taro; Shimizu, Toshifumi; Kobayashi, Ken; Robinson, Brian; Kim,
   Tony; Winebarger, Amy; West, Edward; Cirtain, Jonathan; De Pontieu,
   Bart; Casini, Roberto; Trujillo Bueno, Javier; Stepan, Jiri; Manso
   Sainz, Rafael; Belluzzi, Luca; Asensio Ramos, Andres; Carlsson, Mats
Bibcode: 2011SPIE.8148E..0HN
Altcode: 2011SPIE.8148E..16N
  The solar chromosphere is an important boundary, through which all of
  the plasma, magnetic fields and energy in the corona and solar wind
  are supplied. Since the Zeeman splitting is typically smaller than
  the Doppler line broadening in the chromosphere and transition region,
  it is not effective to explore weak magnetic fields. However, this is
  not the case for the Hanle effect, when we have an instrument with
  high polarization sensitivity (~ 0.1%). "Chromospheric Lyman- Alpha
  SpectroPolarimeter (CLASP)" is the sounding rocket experiment to detect
  linear polarization produced by the Hanle effect in Lyman-alpha line
  (121.567 nm) and to make the first direct measurement of magnetic
  fields in the upper chromosphere and lower transition region. To
  achieve the high sensitivity of ~ 0.1% within a rocket flight (5
  minutes) in Lyman-alpha line, which is easily absorbed by materials,
  we design the optical system mainly with reflections. The CLASP
  consists of a classical Cassegrain telescope, a polarimeter and a
  spectrometer. The polarimeter consists of a rotating 1/2-wave plate
  and two reflecting polarization analyzers. One of the analyzer also
  works as a polarization beam splitter to give us two orthogonal linear
  polarizations simultaneously. The CLASP is planned to be launched in
  2014 summer.

Title: Short telescope design of 1.5-m aperture solar UV visible
    and IR telescope aboard Solar-C
Authors: Suematsu, Y.; Katsukawa, Y.; Shimizu, T.; Ichimoto, K.;
   Horiuchi, T.; Matsumoto, Y.; Takeyama, N.
Bibcode: 2011SPIE.8148E..0DS
Altcode: 2011SPIE.8148E..12S
  We present an optical and thermal design of one of major instrumental
  payload planned for SOLAR-C mission/Plan-B (high resolution
  spectroscopic option): the telescope assembly of Solar Ultra-violet
  Visible and near IR observing Telescope (SUVIT). To accommodate a
  launcher's nosecone size, a wide observing wavelength coverage from UV
  (down to 280 nm) through near IR (up to 1100 nm), and an 0.1 arcsec
  resolution in the field of 200 arcsec diameter, a short telescope
  design was made for a 1.5 m aperture solar Gregorian telescope with
  the compact design of three-mirror collimator unit.

Title: Modeling and verification of the diffraction-limited visible
    light telescope aboard the solar observing satellite HINODE
Authors: Katsukawa, Y.; Suematsu, Y.; Tsuneta, S.; Ichimoto, K.;
   Shimizu, T.
Bibcode: 2011SPIE.8336E..0FK
Altcode: 2011SPIE.8336E..14K
  HINODE, Japanese for "sunrise", is a spacecraft dedicated for
  observations of the Sun, and was launched in 2006 to study the Sun's
  magnetic fields and how their explosive energies propagate through the
  different atmospheric layers. The spacecraft carries the Solar Optical
  Telescope (SOT), which has a 50 cm diameter clear aperture and provides
  a continuous series of diffraction-limited visible light images from
  space. The telescope was developed through international collaboration
  between Japan and US. In order to achieve the diffraction-limited
  performance, thermal and structural modeling of the telescope was
  extensively used in its development phase to predict how the optical
  performance changes dependent on the thermal condition in orbit. Not
  only the modeling, we devoted many efforts to verify the optical
  performance in ground tests before the launch. The verification in
  the ground tests helped us to find many issues, such as temperature
  dependent focus shifts, which were not identified only through the
  thermal-structural modeling. Another critical issue was micro-vibrations
  induced by internal disturbances of mechanical gyroscopes and momentum
  wheels for attitude control of the spacecraft. Because the structural
  modeling was not accurate enough to predict how much the image quality
  was degraded by the micro-vibrations, we measured their transmission
  in a spacecraft-level test.

Title: Tiny Pores Observed by New Solar Telescope and Hinode
Authors: Cho, KyungSuk; Bong, S.; Chae, J.; Kim, Y.; Park, Y.; Ahn,
   K.; Katsukawa, Y.
Bibcode: 2011SPD....42.1903C
Altcode: 2011BAAS..43S.1903C
  Seoul National University and Korea Astronomy and Space Science
  Institute installed Fast Imaging Solar Spectrograph (FISS) in the
  Cude room of the 1.6 m New Solar Telescope (NST) at Big Bear Solar
  Observatory on May 14, 2010. FISS is a unique system that can do
  imaging of H-alpha and Ca II 8542 band simultaneously, which is quite
  suitable for studying of dynamics of chromosphere. To investigate the
  relationship between the photospheric and low-chromospheric motions at
  the pore region, we took a coordinate observation with NST/FISS and
  Hinode/SOT for new emerging active region (AR11117) on October 26,
  2010. In the observed region, we could find two tiny pores and two
  small magnetic concentrations (SMCs), which have similar magnetic
  flux with the pores but do not look dark. Magnetic flux density and
  Doppler velocities at the photosphere are estimated by applying the
  center-of-gravity (COG) method to the HINODE/spectropolarimeter (SP)
  data. The line-of-sight motions above the photosphere are determined
  by adopting the bisector method to the wing spectra of Ha and CaII
  8542 lines. As results, we found the followings. (1)There are upflow
  motion on the pores and downflow motion on the SMCs. (2)Towards the
  CaII 8542 line center, upflow motion decrease and turn to downward
  motion in pores, while the speed of down flow motion increases in
  the SMCs. (3)There is oscillating motion above pores and the SMCs,
  and this motion keep its pattern along the height. (4) As height
  increase, there is a general tendency of the speed shift to downward
  on pores and the SMCs. In this poster, we will present preliminary
  understanding of the coupling of pore dynamics between the photosphere
  and the low-chromosphere.

Title: Chromospheric Diagnostics in the Next Japanese Solar Mission
    SOLAR-C
Authors: Katsukawa, Y.; Solar-C Working Groups
Bibcode: 2011ASPC..437..281K
Altcode:
  The SOLAR-C working group (WG) was established in 2007 to investigate
  scientific and technical feasibility for the next Japanese solar
  mission SOLAR-C whose earliest launch window is 2018. There are two
  conceptual options in SOLAR-C. Option-A is a mission for out-of-ecliptic
  observations of the solar polar regions to understand dynamics
  in the high latitude regions of the Sun, and internal structures
  and dynamo mechanism. The other option, option-B, is a mission for
  high-resolutional spectroscopic and polarimetric observations of the
  solar atmosphere with advanced telescopes. In option-B of SOLAR-C,
  strong emphasis is on measuring chromospheric magnetic fields with a
  precise spectropolarimetric instrument thanks to a large aperture of
  1 to 1.5 m, which is important to understand mechanisms responsible
  for transfer and dissipation of magnetic energies through the solar
  atmosphere.

Title: Temporal downflows in a penumbra
Authors: Jurčák, J.; Katsukawa, Y.
Bibcode: 2010A&A...524A..21J
Altcode:
  <BR /> Aims: We analyze temporal downflow patches that are located
  in a penumbra and have the same polarity of the magnetic field as
  a sunspot umbra. <BR /> Methods: The repetitive 2'' wide raster
  scans of penumbral regions that are taken with one minute cadence by
  the Hinode spectropolarimeter are used to detect the line-of-sight
  velocities in the penumbra from enhanced signals in the wings of
  Stokes V profiles. The lifetimes and positions within penumbra of the
  identified downflow patches are investigated. The plasma properties
  of the downflow patches are determined using the inversions of the
  observed Stokes profiles. <BR /> Results: The temporal downflows
  have lifetimes of up to fourteen minutes. Some of them are related
  to the disappearance or weakening of nearby upflow regions or to the
  chromospheric brightenings. The downflows take place in regions with
  stronger and more vertical magnetic fields than the upflow regions.

Title: A new type of small-scale downflow patches in sunspot penumbrae
Authors: Katsukawa, Y.; Jurčák, J.
Bibcode: 2010A&A...524A..20K
Altcode: 2010arXiv1007.1702K
  Context. Magnetic and flow structures in a sunspot penumbra are created
  by strong interplay between inclined magnetic fields and photospheric
  convection. They exhibit a complex nature that cannot always be
  explained by the well-known Evershed flow. <BR /> Aims: A sunspot
  penumbra is observationally examined to reveal properties of small-scale
  flow structures and their relationship to the filamentary magnetic
  structures and the Evershed flow. We also study how the photospheric
  dynamics are related to chromospheric activities. <BR /> Methods: This
  study is based on data analysis of spectro-polarimetric observations of
  photospheric Fe I lines with the Solar Optical Telescope aboard Hinode
  in a sunspot penumbra at different heliocentric angles. Vector magnetic
  fields and velocities are derived using the spectro-polarimetric
  data and a Stokes inversion technique. An observation with a Ca II H
  filtergram co-spatial and co-temporal with the spectro-polarimetric
  one is also used to study possible chromospheric responses. <BR />
  Results: We find small patches with downflows in the photospheric
  layers. The downflow patches have a size of 0.5'' or smaller and
  a different geometrical configuration from the Evershed flow. The
  downflow velocity is about 1 km s<SUP>-1</SUP> in the lower photspheric
  layers and is almost zero in the upper layers. Some of the downflow
  patches are associated with brightenings seen in Ca II H images. <BR
  /> Conclusions: The downflows are possible observational signatures
  of downward flows driven by magnetic reconnection in the interlaced
  magnetic field configuration, where upward flows make brightenings in
  the chromosphere. Another possibility is that they are concentrated
  downward flows of overturning magnetoconvection.

Title: Quiescent Prominence Dynamics Observed with the Hinode Solar
    Optical Telescope. I. Turbulent Upflow Plumes
Authors: Berger, Thomas E.; Slater, Gregory; Hurlburt, Neal; Shine,
   Richard; Tarbell, Theodore; Title, Alan; Lites, Bruce W.; Okamoto,
   Takenori J.; Ichimoto, Kiyoshi; Katsukawa, Yukio; Magara, Tetsuya;
   Suematsu, Yoshinori; Shimizu, Toshifumi
Bibcode: 2010ApJ...716.1288B
Altcode:
  Hinode/Solar Optical Telescope (SOT) observations reveal two new
  dynamic modes in quiescent solar prominences: large-scale (20-50 Mm)
  "arches" or "bubbles" that "inflate" from below into prominences, and
  smaller-scale (2-6 Mm) dark turbulent upflows. These novel dynamics are
  related in that they are always dark in visible-light spectral bands,
  they rise through the bright prominence emission with approximately
  constant speeds, and the small-scale upflows are sometimes observed to
  emanate from the top of the larger bubbles. Here we present detailed
  kinematic measurements of the small-scale turbulent upflows seen in
  several prominences in the SOT database. The dark upflows typically
  initiate vertically from 5 to 10 Mm wide dark cavities between the
  bottom of the prominence and the top of the chromospheric spicule
  layer. Small perturbations on the order of 1 Mm or less in size
  grow on the upper boundaries of cavities to generate plumes up to
  4-6 Mm across at their largest widths. All plumes develop highly
  turbulent profiles, including occasional Kelvin-Helmholtz vortex
  "roll-up" of the leading edge. The flows typically rise 10-15 Mm before
  decelerating to equilibrium. We measure the flowfield characteristics
  with a manual tracing method and with the Nonlinear Affine Velocity
  Estimator (NAVE) "optical flow" code to derive velocity, acceleration,
  lifetime, and height data for several representative plumes. Maximum
  initial speeds are in the range of 20-30 km s<SUP>-1</SUP>, which
  is supersonic for a ~10,000 K plasma. The plumes decelerate in the
  final few Mm of their trajectories resulting in mean ascent speeds
  of 13-17 km s<SUP>-1</SUP>. Typical lifetimes range from 300 to 1000
  s (~5-15 minutes). The area growth rate of the plumes (observed as
  two-dimensional objects in the plane of the sky) is initially linear
  and ranges from 20,000 to 30,000 km<SUP>2</SUP> s<SUP>-1</SUP> reaching
  maximum projected areas from 2 to 15 Mm<SUP>2</SUP>. Maximum contrast of
  the dark flows relative to the bright prominence plasma in SOT images
  is negative and ranges from -10% for smaller flows to -50% for larger
  flows. Passive scalar "cork movies" derived from NAVE measurements show
  that prominence plasma is entrained by the upflows, helping to counter
  the ubiquitous downflow streams in the prominence. Plume formation
  shows no clear temporal periodicity. However, it is common to find
  "active cavities" beneath prominences that can spawn many upflows in
  succession before going dormant. The mean flow recurrence time in these
  active locations is roughly 300-500 s (5-8 minutes). Locations remain
  active on timescales of tens of minutes up to several hours. Using a
  column density ratio measurement and reasonable assumptions on plume
  and prominence geometries, we estimate that the mass density in the
  dark cavities is at most 20% of the visible prominence density, implying
  that a single large plume could supply up to 1% of the mass of a typical
  quiescent prominence. We hypothesize that the plumes are generated from
  a Rayleigh-Taylor instability taking place on the boundary between
  the buoyant cavities and the overlying prominence. Characteristics,
  such as plume size and frequency, may be modulated by the strength
  and direction of the cavity magnetic field relative to the prominence
  magnetic field. We conclude that buoyant plumes are a source of
  quiescent prominence mass as well as a mechanism by which prominence
  plasma is advected upward, countering constant gravitational drainage.

Title: Magnetic Structure of Umbral Dots with SOT SP
Authors: Watanabe, H.; Kitai, R.; Ichimoto, K.; Katsukawa, Y.
Bibcode: 2009ASPC..415..378W
Altcode:
  High resolution and seeing-free spectroscopic observations of a decaying
  sunspot were done with the Solar Optical Telescope aboard Hinode
  satellite. We report the magnetic structure and Doppler velocity fields
  around umbral dots (UDs), based on the Milne-Eddington inversion of the
  two iron absorption lines at 6302 Å. <P />The histograms of magnetic
  field strength (B), inclination angle (i), and Doppler velocity (v)
  of UDs showed a center-to-limb variation. Observed at the disk center,
  UDs had (i) slightly smaller field strength (ΔB = -17 Gauss) and
  (ii) relative blue shifts (Δv =28 m s<SUP>-1</SUP>) compared to their
  surroundings. When the sunspot approached to the limb, UDs and their
  surroundings showed almost no difference in the magnetic and Doppler
  values. This center-to-limb variation can be understood by the formation
  height difference in a cusp-shaped magnetized atmosphere around UDs,
  due to the weakly magnetized hot gas intrusion. In addition, some UDs
  showed oscillatory light curves with multiple peaks around 10 min,
  which may indicate the presence of the oscillatory convection.

Title: Downflow Patches in a Penumbra Observed with the Hinode
    Spectro-Polarimeter
Authors: Katsukawa, Y.; Jurčák, J.
Bibcode: 2009ASPC..415..117K
Altcode:
  We here present a new observational signature of dynamics in a sunspot
  penumbra. The dynamics are observed as a small patch of downflows
  distributed sparsely in a center-side penumbra, and not observed in
  a limb-side penumbra. The distribution suggests that the downflow is
  aligned to magnetic field lines relatively vertical to the surface. The
  flow might be related to dissipation of magnetic energies in a penumbra.

Title: Supersonic Continuation of the Evershed Flow Outside a Sunspot
    as Observed with Hinode
Authors: Martínez Pillet, V.; Katsukawa, Y.; Puschmann, K. G.;
   Ruiz Cobo, B.
Bibcode: 2009ApJ...701L..79M
Altcode: 2009arXiv0907.3835M
  We report on the discovery of mostly horizontal field channels just
  outside sunspot penumbrae (in the so-called "moat" region) that are
  seen to sustain supersonic flows (line-of-sight component of 6 km
  s<SUP>-1</SUP>). The spectral signature of these supersonic flows
  corresponds to circular polarization profiles with an additional,
  satellite, third lobe of the same sign as the parent sunspot' Stokes
  V blue lobe, for both downflows and upflows. This is consistent with
  an outward directed flow that we interpret as the continuation of the
  magnetized Evershed flow outside sunspots at supersonic speeds. In
  Stokes Q and U, a clear signature of a transverse field connecting
  the two flow streams is observed. Such an easily detectable spectral
  signature should allow for a clear identification of these horizontal
  field channels in other spectropolarimetric sunspot data. For the spot
  analyzed in this paper, a total of five channels with this spectral
  signature have been unambiguously found.

Title: A New View of Fine Scale Dynamics and Magnetism of Sunspots
    Revealed by Hinode/SOT
Authors: Ichimoto, K.; Suematsu, Y.; Katsukawa, Y.; Tsuneta, S.;
   Shimojo, M.; Shimizu, T.; Shine, R. A.; Tarbell, T. D.; Berger, T.;
   Title, A. M.; Lites, B. W.; Kubo, M.; Yokoyama, T.; Nagata, S.
Bibcode: 2009ASPC..405..167I
Altcode:
  The Solar Optical Telescope on-board Hinode is providing a new view of
  the fine scale dynamics in sunspots with its high spatial resolution and
  unprecedented image stability. We present three features related to the
  Evershed flow each of which raises a new puzzle in sunspot dynamics;
  i.e., twisting appearance of penumbral filaments, the source and sink
  of individual Evershed flow channels, and the net circular polarization
  in penumbrae with its spatial relation to the Evershed flow channels.

Title: Has Hinode Revealed the Missing Turbulent Flux of the
    Quiet Sun?
Authors: Lites, B. W.; Kubo, M.; Socas-Navarro, H.; Berger, T.; Frank,
   Z.; Shine, R.; Tarbell, T.; Title, A. M.; Ichimoto, K.; Katsukawa,
   Y.; Tsuneta, S.; Suematsu, Y.; Shimizu, T.; Nagata, S.
Bibcode: 2009ASPC..405..173L
Altcode:
  The Hinode Spectro-Polarimeter has revealed the presence of surprisingly
  strong horizontal magnetic fields nearly everywhere in the quiet
  solar atmosphere. These horizontal fields, along with measures of the
  vertical fields, may be the signature of the ``hidden turbulent flux''
  of the quiet Sun. The measured horizontal fields average at least to
  55 Gauss: nearly 5 times that of the measured longitudinal apparent
  flux density. The nature of these fields are reviewed, and discussed
  in the light of recent magneto-convection numerical simulations of
  the quiet Sun.

Title: Hinode Observation of the Magnetic Fields in a Sunspot Light
    Bridge Accompanied by Long-Lasting Chromospheric Plasma Ejections
Authors: Shimizu, Toshifumi; Katsukawa, Yukio; Kubo, Masahito; Lites,
   Bruce W.; Ichimoto, Kiyoshi; Suematsu, Yoshinori; Tsuneta, Saku;
   Nagata, Shin'ichi; Shine, Richard A.; Tarbell, Theodore D.
Bibcode: 2009ApJ...696L..66S
Altcode:
  We present high-resolution magnetic field measurements of a sunspot
  light bridge (LB) that produced chromospheric plasma ejections
  intermittently and recurrently for more than 1 day. The observations
  were carried out with the Hinode Solar Optical Telescope on 2007
  April 29 and 30. The spectro-polarimeter reveals obliquely oriented
  magnetic fields with vertical electric current density higher than
  100 mA m<SUP>-2</SUP> along the LB. The observations suggest that
  current-carrying highly twisted magnetic flux tubes are trapped below
  a cusp-shaped magnetic structure along the LB. The presence of trapped
  current-carrying flux tubes is essential for causing long-lasting
  chromospheric plasma ejections at the interface with pre-existing
  vertically oriented umbral fields. A bidirectional jet was clearly
  detected, suggesting magnetic reconnections occurring at very low
  altitudes, slightly above the height where the vector magnetic fields
  are measured. Moreover, we found another strong vertical electric
  current on the interface between the current-carrying flux tube
  and pre-existing umbral field, which might be a direct detection
  of the currents flowing in the current sheet formed at the magnetic
  reconnection sites.

Title: Prominence Formation Associated with an Emerging Helical
    Flux Rope
Authors: Okamoto, Takenori J.; Tsuneta, Saku; Lites, Bruce W.; Kubo,
   Masahito; Yokoyama, Takaaki; Berger, Thomas E.; Ichimoto, Kiyoshi;
   Katsukawa, Yukio; Nagata, Shin'ichi; Shibata, Kazunari; Shimizu,
   Toshifumi; Shine, Richard A.; Suematsu, Yoshinori; Tarbell, Theodore
   D.; Title, Alan M.
Bibcode: 2009ApJ...697..913O
Altcode: 2009arXiv0904.0007O
  The formation and evolution process and magnetic configuration of
  solar prominences remain unclear. In order to study the formation
  process of prominences, we examine continuous observations of a
  prominence in NOAA AR 10953 with the Solar Optical Telescope on
  the Hinode satellite. As reported in our previous Letter, we find
  a signature suggesting that a helical flux rope emerges from below
  the photosphere under a pre-existing prominence. Here we investigate
  more detailed properties and photospheric indications of the emerging
  helical flux rope, and discuss their relationship to the formation of
  the prominence. Our main conclusions are: (1) a dark region with absence
  of strong vertical magnetic fields broadens and then narrows in Ca II
  H-line filtergrams. This phenomenon is consistent with the emergence
  of the helical flux rope as photospheric counterparts. The size of the
  flux rope is roughly 30,000 km long and 10,000 km wide. The width is
  larger than that of the prominence. (2) No shear motion or converging
  flows are detected, but we find diverging flows such as mesogranules
  along the polarity inversion line. The presence of mesogranules may
  be related to the emergence of the helical flux rope. (3) The emerging
  helical flux rope reconnects with magnetic fields of the pre-existing
  prominence to stabilize the prominence for the next several days. We
  thus conjecture that prominence coronal magnetic fields emerge in
  the form of helical flux ropes that contribute to the formation and
  maintenance of the prominence.

Title: Magnetic Structure of Umbral Dots Observed with the Hinode
    Solar Optical Telescope
Authors: Watanabe, Hiroko; Kitai, Reizaburo; Ichimoto, Kiyoshi;
   Katsukawa, Yukio
Bibcode: 2009PASJ...61..193W
Altcode: 2008arXiv0811.1074W
  A high-resolution, seeing-free spectroscopic observation of a decaying
  sunspot was made with the Solar Optical Telescope aboard the Hinode
  satellite. The target was NOAA 10944, located in the west side of the
  solar surface from 2007 March 2 to March 4. The umbra included many
  umbral dots (UDs) with a size of ∼300 km in continuum light. We report
  on the magnetic structures and Doppler velocity fields around UDs, based
  on the Milne-Eddington inversions of the two iron absorption lines at
  6302Å. Histograms of the magnetic field strength (B), inclination angle
  (i), and Doppler velocity (v) of UDs showed a center-to-limb variation;
  observed at the disk center, the UDs had (i) slightly smaller field
  strength (ΔB = -17Gauss) and (ii) relative blue shifts (Δv = 28m
  s<SUP>-1</SUP>) compared to their surroundings. When the sunspot
  got close to the limb, UDs and their surroundings showed almost no
  difference in the magnetic and Doppler values. This center-to-limb
  variation can be understood by the formation height difference in
  a cusp-shaped magnetized atmosphere around UDs, due to the weakly
  magnetized hot gas intrusion. In addition, some UDs showed the
  oscillatory light curves with multiple peaks separated around 10min,
  which may indicate the presence of the oscillatory convection. We
  discuss our results within the frameworks of two theoretical models:
  the monolithic model (Schüssler &amp; Vögler 2006, ApJ, 641, L73)
  and the field-free intrusion model (Spruit &amp; Scharmer 2006, A&amp;A,
  447, 343).

Title: The Magnetic Landscape of the Sun's Polar Region
Authors: Tsuneta, S.; Ichimoto, K.; Katsukawa, Y.; Lites, B. W.;
   Matsuzaki, K.; Nagata, S.; Orozco Suárez, D.; Shimizu, T.; Shimojo,
   M.; Shine, R. A.; Suematsu, Y.; Suzuki, T. K.; Tarbell, T. D.; Title,
   A. M.
Bibcode: 2008ApJ...688.1374T
Altcode: 2008arXiv0807.4631T
  We present observations of the magnetic landscape of the polar region
  of the Sun that are unprecedented in terms of spatial resolution,
  field of view, and polarimetric precision. They were carried out with
  the Solar Optical Telescope aboard Hinode. Using a Milne-Eddington
  inversion, we find many vertically oriented magnetic flux tubes
  with field strengths as strong as 1 kG scattered in latitude between
  70° and 90°. They all have the same polarity, consistent with the
  global polarity of the polar region. The field vectors are observed to
  diverge from the centers of the flux elements, consistent with a view
  of magnetic fields that are expanding and fanning out with height. The
  polar region is also found to have ubiquitous horizontal fields. The
  polar regions are the source of the fast solar wind, which is channeled
  along unipolar coronal magnetic fields whose photospheric source is
  evidently rooted in the strong-field, vertical patches of flux. We
  conjecture that vertical flux tubes with large expansion around the
  photospheric-coronal boundary serve as efficient chimneys for Alfvén
  waves that accelerate the solar wind.

Title: Magnetic flux cancellation associated with a recurring solar
    jet observed with Hinode, RHESSI, and STEREO/EUVI
Authors: Chifor, C.; Isobe, H.; Mason, H. E.; Hannah, I. G.; Young,
   P. R.; Del Zanna, G.; Krucker, S.; Ichimoto, K.; Katsukawa, Y.;
   Yokoyama, T.
Bibcode: 2008A&A...491..279C
Altcode:
  Aims: We study the physical properties of a recurring solar active
  region jet observed in X-rays and extreme-ultraviolet (EUV). <BR
  />Methods: Multi-wavelength data from all three instruments on
  board Hinode were analysed. X-ray imaging and spectroscopy of the
  microflaring emission associated with the jets was performed with the
  Reuven Ramaty High Energy Spectroscopic Imager (RHESSI). Associated
  EUV jets were observed with the Sun Earth Connection Coronal and
  Heliospheric Investigation (SECCHI)/Extreme Ultraviolet Imager
  (EUVI) on board STEREO. <BR />Results: We found a correlation between
  recurring magnetic flux cancellation close to a pore, the X-ray jet
  emission, and associated Ca II H ribbon brightenings. We estimated the
  lower limit for the decrease in magnetic energy associated with the
  X-ray jet emission at 3 × 10<SUP>29</SUP> erg. The recurring plasma
  ejection was observed simultaneously at EUV and X-ray temperatures,
  associated with type III radio bursts and microflaring activity at the
  jet footpoint. <BR />Conclusions: The recurring jet (EUV and X-ray)
  emissions can be attributed to chromospheric evaporation flows due to
  recurring coronal magnetic reconnection. In this process, the estimated
  minimum loss in the magnetic energy is sufficient to account for the
  total energy required to launch the jet. <P />Movie of Fig. 3 is only
  available in electronic form via http://www.aanda.org

Title: Magnetic Fields of the Quiet Sun: A New Quantitative
    Perspective From Hinode
Authors: Lites, B. W.; Kubo, M.; Socas-Navarro, H.; Berger, T.; Frank,
   Z.; Shine, R.; Tarbell, T.; Title, A.; Ichimoto, K.; Katsukawa, Y.;
   Tsuneta, S.; Suematsu, Y.; Shimizu, T.; Nagata, S.
Bibcode: 2008ASPC..397...17L
Altcode:
  This article summarizes results of studies presented in two papers
  already published: Lites et al. (2007a); Lites et al. (2007b). Please
  see these for further details.

Title: On-orbit Performance of the Solar Optical Telescope aboard
    Hinode
Authors: Ichimoto, K.; Katsukawa, Y.; Tarbell, T.; Shine, R. A.;
   Hoffmann, C.; Berger, T.; Cruz, T.; Suematsu, Y.; Tsuneta, S.; Shimizu,
   T.; Lites, B. W.
Bibcode: 2008ASPC..397....5I
Altcode: 2008arXiv0804.3248I
  On-orbit performance of the Solar Optical Telescope (SOT) aboard Hinode
  is described with some attention to its unpredicted aspects. In general,
  SOT reveals an excellent performance and has been providing outstanding
  data. Some unexpected features exist, however, in behaviours of the
  focus position, throughput and structural stability. Most of them are
  recovered by the daily operation i.e., frequent focus adjustment,
  careful heater setting and corrections in data analysis. The
  tunable filter contains air bubbles which degrade the data quality
  significantly. Schemes for tuning the filter without disturbing the
  bubbles have been developed and tested, and some useful procedures
  to obtain Dopplergrams and magnetograms are now available. October
  and March, when the orbit of satellite becomes nearly perpendicular
  to the direction towards the Sun, provide a favourable condition for
  continuous runs of the narrow-band filter imager.

Title: Evolution of Magnetic Field and Flow in NOAA 10930 Obtained
    by Hinode Observations
Authors: Magara, T.; Katsukawa, Y.; Ichimoto, K.; Tsuneta, S.;
   Yokoyama, T.; Nagata, S.; Inoue, S.
Bibcode: 2008ASPC..397..135M
Altcode:
  We here present an initial result of investigations into the evolution
  of NOAA 10930 obtained by the Solar Optical Telescope on board
  Hinode. The fine-scale G-band images associated with three components of
  the magnetic field provide useful information on the characteristics
  of this active region. We derived three phases characterizing the
  evolution of magnetic field toward producing an X-class flare. We
  also study the nature of a rapid flow found in this active region by
  investigating the configuration of the magnetic field and flow.

Title: High Resolution Observations of Spicules with Hinode/SOT
Authors: Suematsu, Y.; Ichimoto, K.; Katsukawa, Y.; Shimizu, T.;
   Okamoto, T.; Tsuneta, S.; Tarbell, T.; Shine, R. A.
Bibcode: 2008ASPC..397...27S
Altcode:
  High time cadence unprecedented images at the limb with Ca II H line
  filtergraph from the Solar Optical Telescope (SOT) aboard Hinode
  have revealed that a spicule consists of highly dynamic multi-threads
  (typically twin) as thin as a few tenths of an arcsecond, and shows
  prominent lateral movement or oscillation with rotation on its axis
  during its life. This multi-thread structure and lateral motion indicate
  that the spicules can be driven by magnetic reconnection at unresolved
  spatial scales at their footpoints.

Title: Evolution of Magnetic Fields at the Boundary of the Penumbra
Authors: Kubo, M.; Ichimoto, K.; Shimizu, T.; Lites, B. W.; Tsuneta,
   S.; Suematsu, Y.; Katsukawa, Y.; Nagata, S.; Tarbell, T.; Shine,
   R. A.; Title, A. M.
Bibcode: 2008ASPC..397...79K
Altcode:
  The formation of moving magnetic features (MMFs) separating from the
  penumbra were successfully observed with the Solar Optical Telescope
  (SOT) aboard the Hinode satellite. We find that bright features in
  the outer penumbra are located at the penumbral spines, which have
  magnetic fields more vertical than the surroundings, or located at the
  MMFs separating from the spines. This suggests that convection in the
  outer penumbra is related to the disintegration of the sunspot.

Title: The Properties of Penumbral Microjets - Inclinations and
    Possible Potospheric Response
Authors: Jurcak, J.; Katsukawa, Y.
Bibcode: 2008ESPM...12.2.25J
Altcode:
  The dependence of penumbral microjets inclination on the position
  within penumbra is investigated using the Ca II images taken with Hinode
  SOT. The penumbral microjet inclination is increasing towards the outer
  edge of the penumbra; from 35 deg at the umbra-penumbra boundary up
  to 70 deg at the penumbra/quiet sun boundary. The comparison with the
  inclination of photospheric magnetic field suggest that the penumbral
  microjet follows the opening magnetic field lines of a vertical flux
  tube that creates the sunspot. Another data set of Ca II images with
  simultaneous SP measurements is used to study the possible relation
  between the penumbral microjets and the downflows observed in middle
  of the centre-side penumbra. Some of these downflow patches can be
  associated with the Ca II brightenings and might correspond to the
  reconnection outflow. As is retrieved from the Stokes inversion, the
  downflow preferentially take place in the lower photosphere and this
  may provide a constraint on a reconnection site.

Title: The properties of penumbral microjets inclination
Authors: Jurčák, J.; Katsukawa, Y.
Bibcode: 2008A&A...488L..33J
Altcode: 2008arXiv0808.0757J
  Aims: We investigate the dependence of penumbral microjets inclination
  on the position within penumbra. <BR />Methods: The high cadence
  observations taken on 10 November 2006 with the Hinode satellite
  through the Ca II H and G-band filters were analysed to determine the
  inclination of penumbral microjets. The results were then compared with
  the inclination of the magnetic field determined through the inversion
  of the spectropolarimetric observations of the same region. <BR
  />Results: The penumbral microjet inclination is increasing towards
  the outer edge of the penumbra. The results suggest that the penumbral
  microjet follows the opening magnetic field lines of a vertical flux
  tube that creates the sunspot.

Title: Balloon-Borne Hard X-Ray Spectrometer Using CdTe Detectors
Authors: Kobayashi, K.; Tsuneta, S.; Tamura, T.; Kumagai, K.;
   Katsukawa, Y.; Kubo, M.; Sakamoto, Y.; Kohara, N.; Yamagami, T.;
   Saito, Y.; Mori, K.
Bibcode: 2008SoPh..250..431K
Altcode: 2008SoPh..tmp..132K
  Spectroscopic observation of solar flares in the hard X-ray energy
  range, particularly the 20 ∼ 100 keV region, is an invaluable tool
  for investigating the flare mechanism. This paper describes the design
  and performance of a balloon-borne hard X-ray spectrometer using CdTe
  detectors developed for solar flare observation. The instrument is a
  small balloon payload (gondola weight 70 kg) with sixteen 10×10×0.5
  mm CdTe detectors, designed for a 1-day flight at 41 km altitude. It
  observes in an energy range of 20−120 keV and has an energy resolution
  of 3 keV at 60 keV. The second flight on 24 May 2002 succeeded in
  observing a class M1.1 flare.

Title: Erratum: The Analysis of Penumbral Fine Structure Using an
    Advanced Inversion Technique
Authors: Jurcák, Jan; Bellot Rubio, Luis; Ichimoto, Kiyoshi;
   Katsukawa, Yukio; Lites, Bruce; Nagata, Shin'ichi; Shimizu, Toshifumi;
   Suematsu, Yoshinori; Tarbell, Theodore D.; Title, Alan M.; Tsuneta,
   Saku
Bibcode: 2008PASJ...60..933J
Altcode:
  In the article [PASJ 59, S601-S606 (2007)], the word ''CSIC'' was
  omitted from the affiliation of Dr. Luis Bellot Rubio. The correct
  affiliation is : <SUP>2</SUP>Instituto de Astrofísica de Andalucía
  (CSIC), Apdo. de Correos 3004, 18080 Granada, Spain

Title: Giant Chromospheric Anemone Jet Observed with Hinode and
Comparison with Magnetohydrodynamic Simulations: Evidence of
    Propagating Alfvén Waves and Magnetic Reconnection
Authors: Nishizuka, N.; Shimizu, M.; Nakamura, T.; Otsuji, K.; Okamoto,
   T. J.; Katsukawa, Y.; Shibata, K.
Bibcode: 2008ApJ...683L..83N
Altcode: 2008arXiv0810.3384N
  Hinode discovered a beautiful giant jet with both cool and hot
  components at the solar limb on 2007 February 9. Simultaneous
  observations by the Hinode SOT, XRT, and TRACE 195 Å satellites
  revealed that hot (~5 × 10<SUP>6</SUP> K) and cool (~10<SUP>4</SUP>
  K) jets were located side by side and that the hot jet preceded the
  associated cool jet (~1-2 minutes). A current-sheet-like structure
  was seen in optical (Ca II H), EUV (195 Å), and soft X-ray emissions,
  suggesting that magnetic reconnection is occurring in the transition
  region or upper chromosphere. Alfvén waves were also observed with
  Hinode SOT. These propagated along the jet at velocities of ~200
  km s<SUP>-1</SUP> with amplitudes (transverse velocity) of ~5-15 km
  s<SUP>-1</SUP> and a period of ~200 s. We performed two-dimensional MHD
  simulation of the jets on the basis of the emerging flux-reconnection
  model, by extending Yokoyama and Shibata's model. We extended the model
  with a more realistic initial condition (~10<SUP>6</SUP> K corona) and
  compared our model with multiwavelength observations. The improvement
  of the coronal temperature and density in the simulation model allowed
  for the first time the reproduction of the structure and evolution of
  both the cool and hot jets quantitatively, supporting the magnetic
  reconnection model. The generation and the propagation of Alfvén
  waves are also reproduced self-consistently in the simulation model.

Title: Disintegration of Magnetic Flux in Decaying Sunspots as
    Observed with the Hinode SOT
Authors: Kubo, M.; Lites, B. W.; Ichimoto, K.; Shimizu, T.; Suematsu,
   Y.; Katsukawa, Y.; Tarbell, T. D.; Shine, R. A.; Title, A. M.; Nagata,
   S.; Tsuneta, S.
Bibcode: 2008ApJ...681.1677K
Altcode: 2008arXiv0806.0415K
  Continuous observations of sunspot penumbrae with the Solar Optical
  Telescope aboard Hinode clearly show that the outer boundary of the
  penumbra fluctuates around its averaged position. The penumbral outer
  boundary moves inward when granules appear in the outer penumbra. We
  discover that such granules appear one after another while moving
  magnetic features (MMFs) are separating from the penumbral "spines"
  (penumbral features that have fields that are stronger and more vertical
  than those of their surroundings). These granules that appear in the
  outer penumbra often merge with bright features inside the penumbra
  that move with the spines as they elongate toward the moat region. This
  suggests that convective motions around the penumbral outer boundary are
  related to the disintegration of magnetic flux in the sunspot. We also
  find that dark penumbral filaments frequently elongate into the moat
  region in the vicinity of MMFs that detach from penumbral spines. Such
  elongating dark penumbral filaments correspond to nearly horizontal
  fields extending from the penumbra. Pairs of MMFs with positive and
  negative polarities are sometimes observed along the elongating dark
  penumbral filaments. This strongly supports the notion that such
  elongating dark penumbral filaments have magnetic fields with a "sea
  serpent"-like structure. Evershed flows, which are associated with the
  penumbral horizontal fields, may be related to the detachment of the
  MMFs from the penumbral spines, as well as to the formation of the MMFs
  along the dark penumbral filaments that elongate into the moat region.

Title: Polarization Calibration of the Solar Optical Telescope
    onboard Hinode
Authors: Ichimoto, K.; Lites, B.; Elmore, D.; Suematsu, Y.; Tsuneta,
   S.; Katsukawa, Y.; Shimizu, T.; Shine, R.; Tarbell, T.; Title, A.;
   Kiyohara, J.; Shinoda, K.; Card, G.; Lecinski, A.; Streander, K.;
   Nakagiri, M.; Miyashita, M.; Noguchi, M.; Hoffmann, C.; Cruz, T.
Bibcode: 2008SoPh..249..233I
Altcode: 2008SoPh..tmp...69I
  The Solar Optical Telescope (SOT) onboard Hinode aims to obtain vector
  magnetic fields on the Sun through precise spectropolarimetry of
  solar spectral lines with a spatial resolution of 0.2 - 0.3 arcsec. A
  photometric accuracy of 10<SUP>−3</SUP> is achieved and, after the
  polarization calibration, any artificial polarization from crosstalk
  among Stokes parameters is required to be suppressed below the level
  of the statistical noise over the SOT's field of view. This goal was
  achieved by the highly optimized design of the SOT as a polarimeter,
  extensive analyses and testing of optical elements, and an end-to-end
  calibration test of the entire system. In this paper we review both
  the approach adopted to realize the high-precision polarimeter of the
  SOT and its final polarization characteristics.

Title: Formation Process of a Light Bridge Revealed with Hinode SOT
Authors: Katsukawa, Yukio
Bibcode: 2008AstHe.101..318K
Altcode:
  The Solar Optical Telescope (SOT) on-board Hinode has enabled to
  continously observe fine features created by magnetic fields on the
  solar surface, and is expected to shed light on longstanding puzzles
  on a sunspot. Here presented is an observational study on formation
  process of a light bridge. A light bridge is a photospheric structure
  dividing a sunspot umbra into two parts, and provides implications on
  how strong magnetic flux in a sunspot is broken up by convection.

Title: The Solar Optical Telescope for the Hinode Mission: An Overview
Authors: Tsuneta, S.; Ichimoto, K.; Katsukawa, Y.; Nagata, S.; Otsubo,
   M.; Shimizu, T.; Suematsu, Y.; Nakagiri, M.; Noguchi, M.; Tarbell,
   T.; Title, A.; Shine, R.; Rosenberg, W.; Hoffmann, C.; Jurcevich,
   B.; Kushner, G.; Levay, M.; Lites, B.; Elmore, D.; Matsushita, T.;
   Kawaguchi, N.; Saito, H.; Mikami, I.; Hill, L. D.; Owens, J. K.
Bibcode: 2008SoPh..249..167T
Altcode: 2008SoPh..tmp...74T; 2007arXiv0711.1715T
  The Solar Optical Telescope (SOT) aboard the Hinode satellite
  (formerly called Solar-B) consists of the Optical Telescope Assembly
  (OTA) and the Focal Plane Package (FPP). The OTA is a 50-cm
  diffraction-limited Gregorian telescope, and the FPP includes the
  narrowband filtergraph (NFI) and the broadband filtergraph (BFI), plus
  the Stokes Spectro-Polarimeter (SP). The SOT provides unprecedented
  high-resolution photometric and vector magnetic images of the
  photosphere and chromosphere with a very stable point spread function
  and is equipped with an image-stabilization system with performance
  better than 0.01 arcsec rms. Together with the other two instruments
  on Hinode (the X-Ray Telescope (XRT) and the EUV Imaging Spectrometer
  (EIS)), the SOT is poised to address many fundamental questions about
  solar magnetohydrodynamics. This paper provides an overview; the
  details of the instrument are presented in a series of companion papers.

Title: Frequent Occurrence of High-Speed Local Mass Downflows on
    the Solar Surface
Authors: Shimizu, T.; Lites, B. W.; Katsukawa, Y.; Ichimoto, K.;
   Suematsu, Y.; Tsuneta, S.; Nagata, S.; Kubo, M.; Shine, R. A.; Tarbell,
   T. D.
Bibcode: 2008ApJ...680.1467S
Altcode: 2008arXiv0804.1167S
  We report on new spectropolarimetric measurements with simultaneous
  filter imaging observation, revealing the frequent appearance of
  polarization signals indicating high-speed, probably supersonic,
  downflows that are associated with at least three different
  configurations of magnetic fields in the solar photosphere. The
  observations were carried out with the Solar Optical Telescope on
  board the Hinode satellite. High-speed downflows are excited when a
  moving magnetic feature is newly formed near the penumbral boundary of
  sunspots. Also, a new type of downflows is identified at the edge of
  sunspot umbra that lack accompanying penumbral structures. These may
  be triggered by the interaction of magnetic fields swept by convection
  with well-concentrated magnetic flux. Another class of high-speed
  downflows are observed in quiet Sun and sunspot moat regions. These are
  closely related to the formation of small concentrated magnetic flux
  patches. High-speed downflows of all types are transient time-dependent
  mass motions. These findings suggest that the excitation of supersonic
  mass flows are one of the key observational features of the dynamical
  evolution occurring in magnetic-field fine structures on the solar
  surface.

Title: Cooperative Observation of Ellerman Bombs between the Solar
    Optical Telescope aboard Hinode and Hida/Domeless Solar Telescope
Authors: Matsumoto, Takuma; Kitai, Reizaburo; Shibata, Kazunari;
   Nagata, Shin'ichi; Otsuji, Kenichi; Nakamura, Tahei; Watanabe, Hiroko;
   Tsuneta, Saku; Suematsu, Yoshinori; Ichimoto, Kiyoshi; Shimizu,
   Toshifumi; Katsukawa, Yukio; Tarbell, Theodore D.; Lites, Bruce W.;
   Shine, Richard A.; Title, Alan M.
Bibcode: 2008PASJ...60..577M
Altcode:
  High-resolution CaIIH broad-band filter images of NOAA10933 on 2007
  January 5 were obtained by the Solar Optical Telescope aboard the Hinode
  satellite. Many small-scale (∼1") bright points were observed outside
  the sunspot and inside the emerging flux region. We identified some of
  these bright points with Ellerman bombs (EBs) by using Hα images taken
  by the Domeless Solar Telescope at Hida observatory. The sub-arcsec
  structures of two EBs seen in CaIIH were studied in detail. Our
  observation showed the following two aspects: (1) The CaIIH bright
  points identified with EBs were associated with the bipolar magnetic
  field structures, as reported by previous studies. (2)The structure
  of the CaIIH bright points turned out to consist of the following two
  parts: a central elongated bright core (0.7" × 0.5") located along
  the magnetic neutral line and a diffuse halo (1.2"×1.8").

Title: The Solar Optical Telescope of Solar-B ( Hinode): The Optical
    Telescope Assembly
Authors: Suematsu, Y.; Tsuneta, S.; Ichimoto, K.; Shimizu, T.; Otsubo,
   M.; Katsukawa, Y.; Nakagiri, M.; Noguchi, M.; Tamura, T.; Kato, Y.;
   Hara, H.; Kubo, M.; Mikami, I.; Saito, H.; Matsushita, T.; Kawaguchi,
   N.; Nakaoji, T.; Nagae, K.; Shimada, S.; Takeyama, N.; Yamamuro, T.
Bibcode: 2008SoPh..249..197S
Altcode: 2008SoPh..tmp...26S
  The Solar Optical Telescope (SOT) aboard the Solar-B satellite (Hinode)
  is designed to perform high-precision photometric and polarimetric
  observations of the Sun in visible light spectra (388 - 668 nm)
  with a spatial resolution of 0.2 - 0.3 arcsec. The SOT consists of
  two optically separable components: the Optical Telescope Assembly
  (OTA), consisting of a 50-cm aperture Gregorian with a collimating lens
  unit and an active tip-tilt mirror, and an accompanying Focal Plane
  Package (FPP), housing two filtergraphs and a spectro-polarimeter. The
  optomechanical and optothermal performance of the OTA is crucial to
  attain unprecedented high-quality solar observations. We describe in
  detail the instrument design and expected stable diffraction-limited
  on-orbit performance of the OTA, the largest state-of-the-art solar
  telescope yet flown in space.

Title: The intensity contrast of solar granulation: comparing Hinode
    SP results with MHD simulations
Authors: Danilovic, S.; Gandorfer, A.; Lagg, A.; Schüssler, M.;
   Solanki, S. K.; Vögler, A.; Katsukawa, Y.; Tsuneta, S.
Bibcode: 2008A&A...484L..17D
Altcode: 2008arXiv0804.4230D
  Context: The contrast of granulation is an important quantity
  characterizing solar surface convection. <BR />Aims: We compare the
  intensity contrast at 630 nm, observed using the Spectro-Polarimeter
  (SP) aboard the Hinode satellite, with the 3D radiative MHD simulations
  of Vögler &amp; Schüssler (2007, A&amp;A, 465, L43). <BR />Methods:
  A synthetic image from the simulation is degraded using a theoretical
  point-spread function of the optical system, and by considering other
  important effects. <BR />Results: The telescope aperture and the
  obscuration by the secondary mirror and its attachment spider, reduce
  the simulated contrast from 14.4% to 8.5%. A slight effective defocus
  of the instrument brings the simulated contrast down to 7.5%, close to
  the observed value of 7.0%. <BR />Conclusions: A proper consideration
  of the effects of the optical system and a slight defocus, lead to
  sufficient degradation of the synthetic image from the MHD simulation,
  such that the contrast reaches almost the observed value. The remaining
  small discrepancy can be ascribed to straylight and slight imperfections
  of the instrument, which are difficult to model. Hence, Hinode SP data
  are consistent with a granulation contrast which is predicted by 3D
  radiation MHD simulations.

Title: Moat Flow in the Vicinity of Sunspots for Various Penumbral
    Configurations
Authors: Vargas Domínguez, S.; Rouppe van der Voort, L.; Bonet,
   J. A.; Martínez Pillet, V.; Van Noort, M.; Katsukawa, Y.
Bibcode: 2008ApJ...679..900V
Altcode: 2008arXiv0802.1457V
  High-resolution time series of sunspots have been obtained with
  the Swedish 1 m Solar Telescope between 2003 and 2006 at different
  locations on the solar disk. Proper motions in seven different active
  regions have been studied. The analysis was performed by applying local
  correlation tracking to every series of sunspots, each of them more than
  40 minutes long. The sunspots' shapes include a different variety of
  penumbral configurations. We report on the systematic behavior of the
  large-scale outflows surrounding the sunspots, commonly known as moat
  flows, that are essentially present only when preceded by a penumbra
  not tangential but perpendicular to the sunspot border. We present
  one case for which this rule appears not to be confirmed. We speculate
  that the magnetic neutral line, which is located in the vicinity of the
  anomalous region, might be responsible for blocking the outflow. These
  new results confirm the systematic and strong relation between the
  moat flows and the existence of penumbrae. A comparative statistical
  study between moats and standard granulation is also performed.

Title: Emergence of a helical flux rope and prominence formation
Authors: Okamoto, T. J.; Tsuneta, S.; Lites, B. W.; Kubo, M.; Yokoyama,
   T.; Berger, T. E.; Ichimoto, K.; Katsukawa, Y.; Nagata, S.; Shibata,
   K.; Shimizu, T.; Shine, R. A.; Suematsu, Y.; Tarbell, T. D.; Title,
   A. M.
Bibcode: 2008AGUSMSP43B..06O
Altcode:
  We report a discovery about emergence of a helical flux rope. The
  episode may be related to the formation and evolution of an active
  region prominence. Statistical studies by previous authors indicate that
  numerous prominences have the inverse-polarity configuration suggesting
  the helical magnetic configurations. There are two theoretical
  models about formation of such a coronal helical magnetic field in
  association with prominences: flux rope model and sheared-arcade
  model. We have so far no clear observational evidence to support
  either model. In order to find a clue about the formation of the
  prominence, we had continuous observations of NOAA AR 10953 with the
  SOT during 2007 April 28 to May 9. A prominence was located over the
  polarity inversion line in the south-east of the main sunspot. These
  observations provided us with a time series of vector magnetic fields
  on the photosphere under the prominence. We found four new features:
  (1) The abutting opposite-polarity regions on the two sides along
  the polarity inversion line first grew laterally in size and then
  narrowed. (2) These abutting regions contained vertically-weak,
  but horizontally-strong magnetic fields. (3) The orientations of
  the horizontal magnetic fields along the polarity inversion line on
  the photosphere gradually changed with time from a normal- polarity
  configuration to an inverse-polarity one. (4) The horizontal-magnetic
  field region was blueshifted. These indicate that helical flux rope
  emerges from below the photosphere into the corona along the polarity
  inversion line under the prominence. We suggest that this supply of a
  helical magnetic flux possibly into the corona is related to formation
  and maintenance of active-region prominences.

Title: Photospheric Signature of Penumbral Microjets
Authors: Katsukawa, Y.; Jurcak, J.; Ichimoto, K.; Suemtasu, Y.;
   Tsuneta, S.; Shimizu, T.; Berger, T. E.; Shine, R. A.; Tarbell, T. D.;
   Lites, B. W.
Bibcode: 2008AGUSMSP53A..03K
Altcode:
  HINODE Solar Optical Telescope (SOT) discovered ubiquitous occurrence
  of fine-scale jetlike activities in penumbral chromospheres, which
  are referred to as penumbral microjets. The microjets' small width
  of 400 km and short duration of less than 1 min make them difficult
  to identify in existing ground-based observations. The apparent
  rise velocity is faster than 50km/s and is roughly comparable to
  the Alfven speed in the sunspot chromosphere. These properties of
  penumbral microjets suggest that magnetic reconnection in uncombed
  magnetic field configuration is the most possible cause of penumbral
  microjets. In order to understand magnetic configuration associated with
  penumbral microjets and prove the chromospheric magnetic reconnection
  hypothesis, we investigated relationship between penumbral microjets
  seen in CaIIH images and photospheric magnetic fields measured by
  the HINODE spectro-polarimeter. We found the inclination angles of
  penumbral microjets measured in CaII H images are roughly consistent
  with inclination angles of relatively vertical magnetic field
  component in uncombed magnetic field configuration. In addition,
  strong and transient downflows are observed in the photosphere near
  the boundary of a horizontal flux tube associated with a penumbral
  microjet. The size of the downflow region is about 300km, which is
  close to the width of penumbral microjets seen in CaII H images. The
  downflow velocity of several km/s might be a result of an outflow of
  chromospheric magnetic reconnection and suffer deceleration due to
  the higher density in the photosphere.

Title: Disintegration of Magnetic Flux in Decaying Sunspots as
    Observed with the Hinode/SOT
Authors: Kubo, M.; Lites, B. W.; Ichimoto, K.; Shimizu, T.; Suematsu,
   Y.; Katsukawa, Y.; Tarbell, T. D.; Shine, R. A.; Title, A. M.; Nagata,
   S.; Tsuneta, S.
Bibcode: 2008AGUSMSP31B..01K
Altcode:
  Continuous observations of sunspot penumbrae with the Solar Optical
  Telescope aboard Hinode clearly show that the outer boundary of the
  penumbra fluctuates around its averaged position. The penumbral outer
  boundary moves inward when granules appear in the outer penumbra. We
  discover that such granules appear one after another while moving
  magnetic features (MMFs) are separating from the penumbral "spines"
  (penumbral features having fields that are stronger and more vertical
  than their surroundings). These granules that appear in the outer
  penumbra often merge with bright features inside the penumbra that move
  with spines as they elongate toward the moat region. This suggests that
  convective motions around the penumbral outer boundary are related to
  disintegration of magnetic flux in the sunspot. We also find that dark
  penumbral filaments frequently elongate into the moat region in the
  vicinity of MMFs that detach from penumbral spines. Such elongating
  dark penumbral filaments correspond to nearly horizontal fields
  extending from the penumbra. Pairs of MMFs with positive and negative
  polarities are sometimes observed along the elongating dark penumbral
  filaments. This strongly supports the notion that such elongating dark
  penumbral filaments have magnetic fields with a "sea serpent"-like
  structure. Evershed flows, which are associated with the penumbral
  horizontal fields, may be related to detachment of the MMFs from the
  penumbral spines, as well as to the formation of the MMFs along the
  dark penumbral filaments that elongate into the moat region.

Title: Formation of Solar Magnetic Flux Tubes with Kilogauss Field
    Strength Induced by Convective Instability
Authors: Nagata, Shin'ichi; Tsuneta, Saku; Suematsu, Yoshinori;
   Ichimoto, Kiyoshi; Katsukawa, Yukio; Shimizu, Toshifumi; Yokoyama,
   Takaaki; Tarbell, Theodore D.; Lites, Bruce W.; Shine, Richard A.;
   Berger, Thomas E.; Title, Alan M.; Bellot Rubio, Luis R.; Orozco
   Suárez, David
Bibcode: 2008ApJ...677L.145N
Altcode:
  Convective instability has been a mechanism used to explain
  the formation of solar photospheric flux tubes with kG field
  strength. However, the turbulence of the Earth's atmosphere has
  prevented ground-based observers from examining the hypothesis
  with precise polarimetric measurement on the subarcsecond scale
  flux tubes. Here we discuss observational evidence of this scenario
  based on observations with the Solar Optical Telescope (SOT) aboard
  Hinode. The cooling of an equipartition field strength flux tube
  precedes a transient downflow reaching 6 km s<SUP>-1</SUP> and the
  intensification of the field strength to 2 kG. These observations
  agree very well with the theoretical predictions.

Title: Transient horizontal magnetic fields in solar plage regions
Authors: Ishikawa, R.; Tsuneta, S.; Ichimoto, K.; Isobe, H.; Katsukawa,
   Y.; Lites, B. W.; Nagata, S.; Shimizu, T.; Shine, R. A.; Suematsu,
   Y.; Tarbell, T. D.; Title, A. M.
Bibcode: 2008A&A...481L..25I
Altcode: 2008arXiv0802.1769I
  Aims:We report the discovery of isolated, small-scale emerging
  magnetic fields in a plage region with the Solar Optical Telescope
  aboard Hinode. <BR />Methods: Spectro-polarimetric observations were
  carried out with a cadence of 34 s for the plage region located near
  disc center. The vector magnetic fields are inferred by Milne-Eddington
  inversion. <BR />Results: The observations reveal widespread occurrence
  of transient, spatially isolated horizontal magnetic fields. The
  lateral extent of the horizontal magnetic fields is comparable to
  the size of photospheric granules. These horizontal magnetic fields
  seem to be tossed about by upflows and downflows of the granular
  convection. We also report an event that appears to be driven by the
  magnetic buoyancy instability. We refer to buoyancy-driven emergence
  as type 1 and convection-driven emergence as type 2. Although both
  events have magnetic field strengths of about 600 G, the filling
  factor of type 1 is a factor of two larger than that of type 2. <BR
  />Conclusions: Our finding suggests that the granular convection in
  the plage regions is characterized by a high rate of occurrence of
  granular-sized transient horizontal fields.

Title: Suppression of convection around small magnetic concentrations
Authors: Morinaga, S.; Sakurai, T.; Ichimoto, K.; Yokoyama, T.;
   Shimojo, M.; Katsukawa, Y.
Bibcode: 2008A&A...481L..29M
Altcode:
  Aims: It is well known that convective motions in the photosphere are
  suppressed by magnetic fields. However, it has been difficult to study
  the interaction between convection and small magnetic features, such
  as G-band bright points (GBPs) or pores with polarimetric measurements,
  because of the available spatial resolution (~1´´). This situation is
  changed by the advent of the Spectro-Polarimeter (SP) aboard the Hinode
  satellite, which has 0.3 arcsec spatial resolution. <BR />Methods:
  We analyzed the pore and its surrounding region in NOAA 10940 near the
  disk center. We obtained the field strength and filling factor through
  the Milne-Eddington inversion of the Stokes profiles. We also derived
  the line-of-sight velocity by the shift of the line core. Using these
  physical parameters, we investigated the physical conditions needed to
  suppress the convection. <BR />Results: We found that the convection
  is suppressed, not by the strength of the magnetic field itself,
  but by high concentration of magnetic flux tubes. We also found that
  GBPs and pores are distinguished in terms of the filling factor (f);
  f ≃ 0.6 for GBPs and f=0.8-0.9 for pores.

Title: Net circular polarization of sunspots in high spatial
    resolution
Authors: Ichimoto, K.; Tsuneta, S.; Suematsu, Y.; Katsukawa, Y.;
   Shimizu, T.; Lites, B. W.; Kubo, M.; Tarbell, T. D.; Shine, R. A.;
   Title, A. M.; Nagata, S.
Bibcode: 2008A&A...481L...9I
Altcode:
  Context: Net circular polarization (NCP) of spectral lines in
  sunspots has been most successfully explained by the presense of
  discontinuities in the magnetic field inclination and flow velocity
  along the line-of-sight in the geometry of the embedded flux tube model
  of penumbrae (Δγ-effect). <BR />Aims: The fine scale structure of
  NCP in a sunspot is examined with special attention paid to spatial
  relations of the Evershed flow to confirm the validity of the present
  interpretation of the NCP of sunspots. <BR />Methods: High resolution
  spectro-polarimetric data of a positive-polarity sunspot obtained
  by the Solar Optical Telescope aboard Hinode are analysed. <BR
  />Results: A positive NCP is associated with the Evershed flow
  channels in both limb-side and disk center-side penumbrae and with
  upflows in the penumbra at disk center. The negative NCP in the disk
  center-side penumbra is generated in inter-Evershed flow channels. <BR
  />Conclusions: The first result is apparently inconsistent with the
  current explanation of NCP with the Δγ-effect but rather suggests a
  positive correlation between the magnetic field strength and the flow
  velocity as the cause of the NCP. The second result serves as strong
  evidence for the presence of gas flows in inter-Evershed flow channels.

Title: Hinode SOT Observations of Solar Quiescent Prominence Dynamics
Authors: Berger, Thomas E.; Shine, Richard A.; Slater, Gregory L.;
   Tarbell, Theodore D.; Title, Alan M.; Okamoto, Takenori J.; Ichimoto,
   Kiyoshi; Katsukawa, Yukio; Suematsu, Yoshinori; Tsuneta, Saku; Lites,
   Bruce W.; Shimizu, Toshifumi
Bibcode: 2008ApJ...676L..89B
Altcode:
  We report findings from multihour 0.2'' resolution movies of
  solar quiescent prominences (QPs) observed with the Solar Optical
  Telescope (SOT) on the Hinode satellite. The observations verify
  previous findings of filamentary downflows and vortices in QPs. SOT
  observations also verify large-scale transverse oscillations in QPs,
  with periods of 20-40 minutes and amplitudes of 2-5 Mm. The upward
  propagation speed of several waves is found to be ~10 km s<SUP>-1</SUP>,
  comparable to the sound speed of a 10,000 K plasma, implying that
  the waves are magnetoacoustic in origin. Most significantly, Hinode
  SOT observations reveal that dark, episodic upflows are common in
  QPs. The upflows are 170-700 km in width, exhibit turbulent flow,
  and rise with approximately constant speeds of ~20 km s<SUP>-1</SUP>
  from the base of the prominence to heights of ~10-20 Mm. The upflows
  are visible in both the Ca II H-line and Hα bandpasses of SOT. The new
  flows are seen in about half of the QPs observed by SOT to date. The
  dark upflows resemble buoyant starting plumes in both their velocity
  profile and flow structure. We discuss thermal and magnetic mechanisms
  as possible causes of the plumes.

Title: Emergence of a Helical Flux Rope under an Active Region
    Prominence
Authors: Okamoto, Takenori J.; Tsuneta, Saku; Lites, Bruce W.; Kubo,
   Masahito; Yokoyama, Takaaki; Berger, Thomas E.; Ichimoto, Kiyoshi;
   Katsukawa, Yukio; Nagata, Shin'ichi; Shibata, Kazunari; Shimizu,
   Toshifumi; Shine, Richard A.; Suematsu, Yoshinori; Tarbell, Theodore
   D.; Title, Alan M.
Bibcode: 2008ApJ...673L.215O
Altcode: 2008arXiv0801.1956O
  Continuous observations were obtained of NOAA AR 10953 with the Solar
  Optical Telescope (SOT) on board the Hinode satellite from 2007 April
  28 to May 9. A prominence was located over the polarity inversion
  line (PIL) to the southeast of the main sunspot. These observations
  provided us with a time series of vector magnetic fields on the
  photosphere under the prominence. We found four features: (1) The
  abutting opposite-polarity regions on the two sides along the PIL first
  grew laterally in size and then narrowed. (2) These abutting regions
  contained vertically weak but horizontally strong magnetic fields. (3)
  The orientations of the horizontal magnetic fields along the PIL on
  the photosphere gradually changed with time from a normal-polarity
  configuration to an inverse-polarity one. (4) The horizontal magnetic
  field region was blueshifted. These indicate that helical flux rope
  was emerging from below the photosphere into the corona along the PIL
  under the preexisting prominence. We suggest that this supply of a
  helical magnetic flux to the corona is associated with evolution and
  maintenance of active region prominences.

Title: The Horizontal Magnetic Flux of the Quiet-Sun Internetwork
    as Observed with the Hinode Spectro-Polarimeter
Authors: Lites, B. W.; Kubo, M.; Socas-Navarro, H.; Berger, T.; Frank,
   Z.; Shine, R.; Tarbell, T.; Title, A.; Ichimoto, K.; Katsukawa, Y.;
   Tsuneta, S.; Suematsu, Y.; Shimizu, T.; Nagata, S.
Bibcode: 2008ApJ...672.1237L
Altcode:
  Observations of very quiet Sun using the Solar Optical
  Telescope/Spectro-Polarimeter (SOT/SP) aboard the Hinode spacecraft
  reveal that the quiet internetwork regions are pervaded by horizontal
  magnetic flux. The spatial average horizontal apparent flux density
  derived from wavelength-integrated measures of Zeeman-induced linear
  polarization is B<SUP>T</SUP><SUB>app</SUB> = 55 Mx cm <SUP>-2</SUP>, as
  compared to the corresponding average vertical apparent flux density of
  | B<SUP>L</SUP><SUB>app</SUB>| = 11 Mx cm <SUP>-2</SUP>. Distributions
  of apparent flux density are presented. Magnetic fields are organized on
  mesogranular scales, with both horizontal and vertical fields showing
  "voids" of reduced flux density of a few granules spatial extent. The
  vertical fields are concentrated in the intergranular lanes, whereas the
  stronger horizontal fields are somewhat separated spatially from the
  vertical fields and occur most commonly at the edges of the bright
  granules. High-S/N observations from disk center to the limb help
  to constrain possible causes of the apparent imbalance between |
  B<SUP>L</SUP><SUB>app</SUB>| and B<SUP>T</SUP><SUB>app</SUB>, with
  unresolved structures of linear dimension on the surface smaller by at
  least a factor of 2 relative to the SOT/SP angular resolution being one
  likely cause of this discrepancy. Other scenarios for explaining this
  imbalance are discussed. The horizontal fields are likely the source of
  the "seething" fields of the quiet Sun discovered by Harvey et al. The
  horizontal fields may also contribute to the "hidden" turbulent flux
  suggested by studies involving Hanle effect depolarization of scattered
  radiation.

Title: Giant chromospheric jet observed with Hinode and magnetic
    reconnection model
Authors: Nishizuka, Naoto; Shimizu, Masaki; Nakamura, Tahei; Otsuji,
   Kenichi; Okamoto, Takenori; Shibata, Kazunari; Katsukawa, Yukio
Bibcode: 2008cosp...37.2239N
Altcode: 2008cosp.meet.2239N
  Heating of the solar chromosphere and corona is one of the long-standing
  puzzles in astronomy and also a key to understand the Sun-Earth
  connection through solar wind and EUV/X-ray radiation. A solar space
  telescope mission Hinode revealed that solar chromosphere is much more
  dynamic than had been thought and is full of tiny jets, which may be
  a key to resolve the puzzle of chromospheric and coronalheating. It
  has long been observed that H-alpha jets called surges often occur in
  the chromosphere. They have been believed to be produced by magnetic
  reconnection, which is an energy conversion mechanism from magnetic
  energy into thermal and kinetic energies of plasma when anti-parallel
  magnetic fields encounter and reconnect with each other. Hinode's
  new chromospheric observations (with Calcium II H broad band filter)
  revealed that jets are ubiquitous in the chromosphere and some of the
  jets show evidence of magnetic reconnection. However, there have not
  been simultaneous observations of the chromospheric jets at X-ray,
  EUV, and Optical (at Calcium II H line) wavelengths until now. Here
  we report first multi-wavelength observations of a chromospheric
  jet with Solar Optical Telescope (SOT) and X-Ray Telescope (XRT)
  on board Hinode and TRACE 195A filter. With its unprecedented high
  quality instruments at both optical and X-rays, Hinode discovered a
  beautiful, giant jet with both cool (104 K) and hot (5x106 K) components
  at the solar limb. TRACE satellite also observed the same jet with
  EUV telescope and revealed the existence of both hot (106 K) and cool
  (unknown temperature) components. These data set are probably the best
  multi-wavelength observations of solar jets until now. We also performed
  magnetohydrodynamic simulation of the jet based on the reconnection
  model and found that it can explain various observational facts very
  well. It has often been argued that some of solar jets are produced by
  magnetic reconnection, but previous observations had a limitation on
  spatial and temporal resolutions and temperature coverage. Using these
  new data and twodimensional magnetohydrodynamic simulations of the jet,
  we showed, for the first time, how hot and cool jets are heated and
  accelerated during the reconnection, including associated generation of
  Alfvén waves. This jet formation dynamics would show a proto-tyep of
  reconnection e model of solar jets and can be applied for other small
  jets discovered by Hinode, which might heat the chromosphere and corona.

Title: Hinode Observations of Flux Emergence in Quiet and Active
    Regions
Authors: Lites, B. W.; Centeno, R.; Kubo, M.; Socas-Navarro, H. Berger,
   T.; Frank, Z.; Shine, R.; Tarbell, T.; Title, A.; Ichimoto, K.;
   Katsukawa, Y.; Tsuneta, S.; Suematsu, Y.; Shimizu, T.; Nagata, S.
Bibcode: 2008ASPC..383...71L
Altcode:
  We review briefly the observational understanding of emergence of
  flux in both the quiet Sun and active regions in the light of first
  results from the joint Japan/US/UK Hinode mission. That spacecraft
  is now providing us with our first continuous, high resolution
  measurements of the photospheric vector magnetic field, along with
  high resolution observations of the thermal and dynamic properties
  of the chromosphere and corona. This review is intended to present a
  few very early results and to highlight the potential for discovery
  offered by this extraordinary new mission. The discovery of ubiquitous
  horizontal magnetic flux in the quiet internetwork regions is presented.

Title: Photospheric activities inside sunspots and their relationship
    with heating of the upper atmosphere
Authors: Katsukawa, Yukio
Bibcode: 2008cosp...37.1466K
Altcode: 2008cosp.meet.1466K
  HINODE Solar Optical Telescope (SOT) allows us to see photospheric
  magnetic structures and their temporal evolution with stable and
  uniform image quality. A sunspot especially provides us with a unique
  site to understand interaction between very stong magnetic fields and
  convective flows, and exhibits various kinds of magnetic activties:
  Continual inward migration of leading edges of penumbral filaments,
  emergence of umbral dots in a peripheral region of an umbra, formation
  of a light bridge, and rapid motion of umbral dots associated with
  the formation of a light bridge, etc. Chromospheric activities are
  also observed directly associated with these photospheric magnetic
  activities. Penumbral microjets, which are newly discoverd by HINODE as
  thin and transient jetlike activities in the penumbral chromospheres,
  are mostly found near a leading edge of penumbral filaments migrating
  inward to an umbra. Surges are sometimes observed above a light
  bridge. It is still an open question how these photospheric and
  chromospheric activities influence the corona. Motion of umbral dots are
  observed not only in a peripherial region of an umbra but in deep insdie
  an umbra. The proper motion of central umbral dots is about 0.1 - 0.5
  km/s, which is slower than that of the peripheral ones. If the motion
  of the umbral dots takes along magnetic field lines, it should provide
  substantial amount of Poynting flux to the upper atmosphere by shaking
  very strong magnetic field lines inside sunspots even with such a slow
  velocity. Nevertheless, the corona above a sunspot umbra is generally
  dark in X-rays, which implys no significant heating there. The observed
  motion of the umbral dots does not necessarily mean the motion of
  magnetic field lines, but can be the motion of the hot gas penetrating
  into the strongly magnetized atmosphere from the subphotosphere along
  a fiele-free gap, which might explain less heating above sunspot umbrae.

Title: Mangetic field properties at the footpoints of solar
    microflares (active-region transient brightenings)
Authors: Shimizu, T.; Kano, R.; Katsukawa, Y.; Kubo, M.; Deluca, E.;
   Ichimoto, K.; Lites, B.; Nagata, S.; Sakao, T.; Shine, R.; Suematsu,
   Y.; Tarbell, T.; Title, A.; Tsuneta, S.
Bibcode: 2007AGUFMSH52C..06S
Altcode:
  Solar active regions produce numerous numbers of small-scale explosive
  energy releases, i.e., microflares, which are captured by imaging
  observations in soft X-rays as transient brightenings of small-scale
  coronal loops. Thanks to advanced performance of X-Ray Telescope (XRT)
  onboard the Hinode satellite, we can investigate finer structure
  of the brightening X-ray sources in more details than we did with
  Yohkoh data. One of important questions on microflares is what causes
  microflares. The simultaneous visible-light observations by the Solar
  Optical Telescope (SOT) allow us to explore magnetic activities
  and magnetic field configuration at the photospheric footpoints
  of brightening loops, giving key observations to investigate the
  question. For our investigations of corona-photosphere magnetic
  coupling, we have established co-alignment between SOT and XRT
  with accuracy better than 1 arcsec (Shimizu et al. 2007, PASJ in
  press). It turns out that Ca II H observations are very useful
  to identify the exact positions of footpoints of X-ray transient
  brightening loops. Small "Kernels" are sometimes observed in Ca II H
  and they may be signature of highly accelerated non-thermal particles
  impinging on chromosphere. As already shown in Shimizu et al.(2002),
  frequent transient brightenings are observed at the locations where
  emerging activities are on going. However, another type of brightening
  triggering mechanism should exist to explain some observed multiple-loop
  brightenings. In the multiple-loop brightenings, multiple loops are
  magnetically in parallel with each other and no apparent magnetic
  activities, such as emerging and canceling, are observed at and near
  the footpoints. This paper will present SOT observations of some
  microflares observed with XRT.

Title: Small-Scale Jetlike Features in Penumbral Chromospheres
Authors: Katsukawa, Y.; Berger, T. E.; Ichimoto, K.; Lites, B. W.;
   Nagata, S.; Shimizu, T.; Shine, R. A.; Suematsu, Y.; Tarbell, T. D.;
   Title, A. M.; Tsuneta, S.
Bibcode: 2007Sci...318.1594K
Altcode:
  We observed fine-scale jetlike features, referred to as penumbral
  microjets, in chromospheres of sunspot penumbrae. The microjets
  were identified in image sequences of a sunspot taken through a Ca II
  H-line filter on the Solar Optical Telescope on board the Japanese solar
  physics satellite Hinode. The microjets’ small width of 400 kilometers
  and short duration of less than 1 minute make them difficult to identify
  in existing observations. The microjets are possibly caused by magnetic
  reconnection in the complex magnetic configuration in penumbrae and
  have the potential to heat the corona above a sunspot.

Title: Chromospheric Alfvénic Waves Strong Enough to Power the
    Solar Wind
Authors: De Pontieu, B.; McIntosh, S. W.; Carlsson, M.; Hansteen,
   V. H.; Tarbell, T. D.; Schrijver, C. J.; Title, A. M.; Shine, R. A.;
   Tsuneta, S.; Katsukawa, Y.; Ichimoto, K.; Suematsu, Y.; Shimizu, T.;
   Nagata, S.
Bibcode: 2007Sci...318.1574D
Altcode:
  Alfvén waves have been invoked as a possible mechanism for the heating
  of the Sun's outer atmosphere, or corona, to millions of degrees and
  for the acceleration of the solar wind to hundreds of kilometers per
  second. However, Alfvén waves of sufficient strength have not been
  unambiguously observed in the solar atmosphere. We used images of
  high temporal and spatial resolution obtained with the Solar Optical
  Telescope onboard the Japanese Hinode satellite to reveal that the
  chromosphere, the region sandwiched between the solar surface and
  the corona, is permeated by Alfvén waves with strong amplitudes on
  the order of 10 to 25 kilometers per second and periods of 100 to
  500 seconds. Estimates of the energy flux carried by these waves and
  comparisons with advanced radiative magnetohydrodynamic simulations
  indicate that such Alfvén waves are energetic enough to accelerate
  the solar wind and possibly to heat the quiet corona.

Title: Chromospheric Anemone Jets as Evidence of Ubiquitous
    Reconnection
Authors: Shibata, Kazunari; Nakamura, Tahei; Matsumoto, Takuma; Otsuji,
   Kenichi; Okamoto, Takenori J.; Nishizuka, Naoto; Kawate, Tomoko;
   Watanabe, Hiroko; Nagata, Shin'ichi; UeNo, Satoru; Kitai, Reizaburo;
   Nozawa, Satoshi; Tsuneta, Saku; Suematsu, Yoshinori; Ichimoto, Kiyoshi;
   Shimizu, Toshifumi; Katsukawa, Yukio; Tarbell, Theodore D.; Berger,
   Thomas E.; Lites, Bruce W.; Shine, Richard A.; Title, Alan M.
Bibcode: 2007Sci...318.1591S
Altcode: 2008arXiv0810.3974S
  The heating of the solar chromosphere and corona is a long-standing
  puzzle in solar physics. Hinode observations show the ubiquitous
  presence of chromospheric anemone jets outside sunspots in active
  regions. They are typically 3 to 7 arc seconds = 2000 to 5000 kilometers
  long and 0.2 to 0.4 arc second = 150 to 300 kilometers wide, and their
  velocity is 10 to 20 kilometers per second. These small jets have an
  inverted Y-shape, similar to the shape of x-ray anemone jets in the
  corona. These features imply that magnetic reconnection similar to that
  in the corona is occurring at a much smaller spatial scale throughout
  the chromosphere and suggest that the heating of the solar chromosphere
  and corona may be related to small-scale ubiquitous reconnection.

Title: Twisting Motions of Sunspot Penumbral Filaments
Authors: Ichimoto, K.; Suematsu, Y.; Tsuneta, S.; Katsukawa, Y.;
   Shimizu, T.; Shine, R. A.; Tarbell, T. D.; Title, A. M.; Lites, B. W.;
   Kubo, M.; Nagata, S.
Bibcode: 2007Sci...318.1597I
Altcode:
  The penumbra of a sunspot is composed of numerous thin, radially
  extended, bright and dark filaments carrying outward gas flows
  (the Evershed flow). Using high-resolution images obtained by the
  Solar Optical Telescope aboard the solar physics satellite Hinode, we
  discovered a number of penumbral bright filaments revealing twisting
  motions about their axes. These twisting motions are observed only
  in penumbrae located in the direction perpendicular to the symmetry
  line connecting the sunspot center and the solar disk center, and
  the direction of the twist (that is, lateral motions of intensity
  fluctuation across filaments) is always from limb side to disk-center
  side. Thus, the twisting feature is not an actual twist or turn of
  filaments but a manifestation of dynamics of penumbral filaments with
  three-dimensional radiative transfer effects.

Title: Continuous Plasma Outflows from the Edge of a Solar Active
    Region as a Possible Source of Solar Wind
Authors: Sakao, Taro; Kano, Ryouhei; Narukage, Noriyuki; Kotoku,
   Jun'ichi; Bando, Takamasa; DeLuca, Edward E.; Lundquist, Loraine L.;
   Tsuneta, Saku; Harra, Louise K.; Katsukawa, Yukio; Kubo, Masahito;
   Hara, Hirohisa; Matsuzaki, Keiichi; Shimojo, Masumi; Bookbinder, Jay
   A.; Golub, Leon; Korreck, Kelly E.; Su, Yingna; Shibasaki, Kiyoto;
   Shimizu, Toshifumi; Nakatani, Ichiro
Bibcode: 2007Sci...318.1585S
Altcode:
  The Sun continuously expels a huge amount of ionized material into
  interplanetary space as the solar wind. Despite its influence on the
  heliospheric environment, the origin of the solar wind has yet to
  be well identified. In this paper, we report Hinode X-ray Telescope
  observations of a solar active region. At the edge of the active region,
  located adjacent to a coronal hole, a pattern of continuous outflow of
  soft-x-ray emitting plasmas was identified emanating along apparently
  open magnetic field lines and into the upper corona. Estimates of
  temperature and density for the outflowing plasmas suggest a mass
  loss rate that amounts to ~1/4 of the total mass loss rate of the
  solar wind. These outflows may be indicative of one of the solar wind
  sources at the Sun.

Title: Hinode SOT observations of plume upflows and cascading
    downflows in quiescent solar prominences
Authors: Berger, T.; Shine, R.; Slater, G.; Tarbell, T.; Title, A.;
   Lites, B.; Tsuneta, S.; Okamoto, T. J.; Ichimoto, K.; Katsukawa, Y.;
   Sekii, T.; Suematsu, Y.; Shimizu, T.
Bibcode: 2007AGUFMSH53A1065B
Altcode:
  We present several Hinode SOT filtergram movies of quiescent solar
  prominences that show newly discovered "plume-like" upflows and
  cascading "waterfall-like" downflows that persist for the entire
  multi-hour duration of the observations. The flow speeds are on the
  order of 10 km/sec with typical widths of 400-700 km. Preliminary
  calculations show that if the upflows are buoyancy driven, the
  associated thermal perturbation is on the order of 10,000 K, sufficient
  to explain the dark appearance of the upflows in the interference
  filter passbands. In addition we observe rotational vortices and
  body oscillations within the prominences. These new observations
  challenge current magnetostatic models of solar prominences by showing
  that prominence plasmas are in constant motion, often in directions
  perpendicular to the magnetic field lines proposed by the models. TRACE,
  Hinode/EIS, and Hinode/XRT observations are used to investigate the
  differential topology of the flows across temperature regimes.

Title: Coronal Transverse Magnetohydrodynamic Waves in a Solar
    Prominence
Authors: Okamoto, T. J.; Tsuneta, S.; Berger, T. E.; Ichimoto, K.;
   Katsukawa, Y.; Lites, B. W.; Nagata, S.; Shibata, K.; Shimizu, T.;
   Shine, R. A.; Suematsu, Y.; Tarbell, T. D.; Title, A. M.
Bibcode: 2007Sci...318.1577O
Altcode: 2008arXiv0801.1958O
  Solar prominences are cool 10<SUP>4</SUP> kelvin plasma clouds
  supported in the surrounding 10<SUP>6</SUP> kelvin coronal plasma by
  as-yet-undetermined mechanisms. Observations from Hinode show fine-scale
  threadlike structures oscillating in the plane of the sky with periods
  of several minutes. We suggest that these represent Alfvén waves
  propagating on coronal magnetic field lines and that these may play
  a role in heating the corona.

Title: Quiet-Sun Internetwork Magnetic Fields from the Inversion of
    Hinode Measurements
Authors: Orozco Suárez, D.; Bellot Rubio, L. R.; del Toro Iniesta,
   J. C.; Tsuneta, S.; Lites, B. W.; Ichimoto, K.; Katsukawa, Y.; Nagata,
   S.; Shimizu, T.; Shine, R. A.; Suematsu, Y.; Tarbell, T. D.; Title,
   A. M.
Bibcode: 2007ApJ...670L..61O
Altcode: 2007arXiv0710.1405O
  We analyze Fe I 630 nm observations of the quiet Sun at disk center
  taken with the spectropolarimeter of the Solar Optical Telescope aboard
  the Hinode satellite. A significant fraction of the scanned area,
  including granules, turns out to be covered by magnetic fields. We
  derive field strength and inclination probability density functions from
  a Milne-Eddington inversion of the observed Stokes profiles. They show
  that the internetwork consists of very inclined, hG fields. As expected,
  network areas exhibit a predominance of kG field concentrations. The
  high spatial resolution of Hinode's spectropolarimetric measurements
  brings to an agreement the results obtained from the analysis of
  visible and near-infrared lines.

Title: Center-to-Limb Variation of Stokes V Asymmetries in Solar
    Pores Observed with the Hinode Spectro-Polarimeter
Authors: Morinaga, Shuji; Nagata, Shin'ichi; Ichimoto, Kiyoshi;
   Suematsu, Yoshinori; Tsuneta, Saku; Katsukawa, Yukio; Shimizu,
   Toshifumi; Shine, Richard A.; Tarbell, Theodore D.; Title, Alan M.;
   Lites, Bruce; Kubo, Masahito; Sakurai, Takashi
Bibcode: 2007PASJ...59S.613M
Altcode:
  Here we present spectro-polarimetric measurements of several pores
  and the surrounding regions taken with the Solar Optical Telescope
  aboard Hinode at various viewing angles. We analyzed the Stokes V
  area asymmetry, and confirmed that it is depressed at the center of
  the pores, while it shows large positive values (a blue lobe larger
  than a red lobe) in the surrounding area; this is consistent with a
  previous report. In addition to this ring of positive asymmetry, we
  found regions of alternating positive and negative area asymmetries
  when weak V regions were observed near the solar limb. The positive
  asymmetry occurs on the disk-center side and the negative asymmetry
  on the limb side of the magnetic concentrations. These center-to-limb
  variations of the Stokes V area asymmetry can be interpreted as being
  a systematic inflow of plasma into the magnetic concentrations from
  their surroundings.

Title: Initial Results on Line-of-Sight Field Calibrations of SP/NFI
    Data Taken by SOT/Hinode
Authors: Chae, Jongchul; Moon, Yong-Jae; Park, Young-Deuk; Ichimoto,
   Kiyoshi; Sakurai, Takashi; Suematsu, Yoshinori; Tsuneta, Saku;
   Katsukawa, Yukio; Shimizu, Toshifumi; Shine, Richard A.; Tarbell,
   Theodore D.; Title, Alan M.; Lites, Bruce; Kubo, Masahito; Nagata,
   Shin'ichi; Yokoyama, Takaaki
Bibcode: 2007PASJ...59S.619C
Altcode:
  We present initial results on the line-of-sight field calibration
  of the two kinds of Stokes I and V data taken by the Solar Optical
  Telescope on the satellite Hinode: spectral profiles of Stokes I and V
  parameters recorded on the Spectro-polarimeter (SP), and monochromatic
  images of the same parameters recorded on the Narrow-band Filter Imager
  (NFI). By applying the center-of-gravity method to the SP data of
  AR10930 taken on 2006 December 11, we determined the line-of-sight field
  at every location in the active region. As a result, we found that the
  line-of-sight field strength ranges up to 2kG in plages, even without
  taking into account the filling factor, and up to 3.5kG or higher values
  inside the umbra of the major sunspot. We calibrated the NFI data in
  reference to the field determined from the SP data. In regions outside
  the sunspots and the penumbral regions, we adopted a linear relation,
  B<SUB>||</SUB> = βV / I, between the circular polarization, V / I,
  and the line-of-sight field strength, B<SUB>||</SUB>, and obtained β =
  23.5kG in regions outside the sunspots, and β = 12.0kG in penumbral
  regions. In umbral regions of sunspots, a first-order polynomial was
  adopted to model the reversal of the polarization signal over the
  field strength.

Title: Response of the Solar Atmosphere to Magnetic Flux Emergence
    from Hinode Observations
Authors: Li, Hui; Sakurai, Takashi; Ichimito, Kiyoshi; Suematsu,
   Yoshinori; Tsuneta, Saku; Katsukawa, Yukio; Shimizu, Toshifumi; Shine,
   Richard A.; Tarbell, Theodore D.; Title, Alan M.; Lites, Bruce; Kubo,
   Masahito; Nagata, Shin'ichi; Kotoku, Jun; Shibasaki, Kiyoto; Saar,
   Steven H.; Bobra, Monica
Bibcode: 2007PASJ...59S.643L
Altcode:
  No abstract at ADS

Title: Initial Helioseismic Observations by Hinode/SOT
Authors: Sekii, Takashi; Kosovichev, Alexander G.; Zhao, Junwei;
   Tsuneta, Saku; Shibahashi, Hiromoto; Berger, Thomas E.; Ichimoto,
   Kiyoshi; Katsukawa, Yukio; Lites, Bruce; Nagata, Shin'ichi; Shimizu,
   Toshifumi; Shine, Richard A.; Suematsu, Yoshinori; Tarbell, Theodore
   D.; Title, Alan M.
Bibcode: 2007PASJ...59S.637S
Altcode: 2007arXiv0709.1806S
  Results from initial helioseismic observations by the Solar Optical
  Telescope on-board Hinode are reported. It has been demonstrated
  that intensity oscillation data from the Broadband Filter Imager
  can be used for various helioseismic analyses. The k - ω power
  spectra, as well as the corresponding time-distance cross-correlation
  function, which promise high-resolution time-distance analysis below
  the 6-Mm travelling distance, were obtained for G-band and CaII-H
  data. Subsurface supergranular patterns were observed from our first
  time-distance analysis. The results show that the solar oscillation
  spectrum is extended to much higher frequencies and wavenumbers, and
  the time-distance diagram is extended to much shorter travel distances
  and times than were observed before, thus revealing great potential
  for high-resolution helioseismic observations from Hinode.

Title: Magnetic Feature and Morphological Study of X-Ray Bright
    Points with Hinode
Authors: Kotoku, Jun'ichi; Kano, Ryouhei; Tsuneta, Saku; Katsukawa,
   Yukio; Shimizu, Toshifumi; Sakao, Taro; Shibazaki, Kiyoto; Deluca,
   Edward E.; Korreck, Kelly E.; Golub, Leon; Bobra, Monica
Bibcode: 2007PASJ...59S.735K
Altcode:
  We observed X-ray bright points (XBPs) in a quiet region of the Sun
  with the X-Ray Telescope (XRT) aboard the Hinode satellite on 2006
  December 19. XRT's high-resolution X-ray images revealed many XBPs with
  complicated structure and evolving dramatically with time. Almost all
  of the dynamic eruptions in the quiet region were composed of XBPs,
  and they had either loop or multiloop shapes, as is observed in larger
  flares. Brightening XBPs had strong magnetic fields with opposite
  polarities near their footpoints. While we have found a possible
  example of associated magnetic cancellation, other XBPs brighten and
  fade without any associated movement of the photospheric magnetic field.

Title: Hinode Observations of Horizontal Quiet Sun Magnetic Flux
    and the ``Hidden Turbulent Magnetic Flux''
Authors: Lites, Bruce; Socas-Navarro, Hector; Kubo, Masahito; Berger,
   Thomas; Frank, Zoe; Shine, Richard A.; Tarbell, Theodore D.; Title,
   Alan M.; Ichimoto, Kiyoshi; Katsukawa, Yukio; Tsuneta, Saku; Suematsu,
   Yoshinori; Shimizu, Toshifumi
Bibcode: 2007PASJ...59S.571L
Altcode:
  We present observations of magnetic fields of the very quiet Sun
  near disk center using the Spectro-Polarimeter of the Solar Optical
  Telescope aboard the Hinode satellite. These observations reveal for
  the first time the ubiquitous presence of horizontal magnetic fields in
  the internetwork regions. The horizontal fields are spatially distinct
  from the vertical fields, demonstrating that they are not arising mainly
  from buffeting of vertical flux tubes by the granular convection. The
  horizontal component has an average ``apparent flux density'' of
  55Mxcm<SUP>-2</SUP> (assuming the horizontal field structures are
  spatially resolved), in contrast to the average apparent vertical flux
  density of 11Mxcm<SUP>-2</SUP>. The vertical fields reside mainly in
  the intergranular lanes, whereas the horizontal fields occur mainly
  over the bright granules, with a preference to be near the outside
  edge of the bright granules. The large apparent imbalance of vertical
  and horizontal flux densities is discussed, and several scenarios are
  presented to explain this imbalance.

Title: Strategy for the Inversion of Hinode Spectropolarimetric
    Measurements in the Quiet Sun
Authors: Orozco Suárez, David; Bellot Rubio, Luis R.; Del Toro
   Iniesta, Jose Carlos; Tsuneta, Saku; Lites, Bruce; Ichimoto, Kiyoshi;
   Katsukawa, Yukio; Nagata, Shin'ichi; Shimizu, Toshifumi; Shine,
   Richard A.; Suematsu, Yoshinori; Tarbell, Theodore D.; Title, Alan M.
Bibcode: 2007PASJ...59S.837O
Altcode: 2007arXiv0709.2033O
  In this paper we propose an inversion strategy for the analysis of
  spectropolarimetric measurements taken by Hinode in the quiet Sun. The
  Spectro-Polarimeter of the Solar Optical Telescope aboard Hinode records
  the Stokes spectra of the FeI line pair at 630.2nm with unprecendented
  angular resolution, high spectral resolution, and high sensitivity. We
  discuss the need to consider a local stray-light contamination to
  account for the effects of telescope diffraction. The strategy is
  applied to observations of a wide quiet Sun area at disk center. Using
  these data we examine the influence of noise and initial guess models
  in the inversion results. Our analysis yields the distributions of
  magnetic field strengths and stray-light factors. They show that quiet
  Sun internetwork regions consist mainly of hG fields with stray-light
  contamination of about 0.8.

Title: Hinode Calibration for Precise Image Co-Alignment between
    SOT and XRT (2006 November-2007 April)
Authors: Shimizu, Toshifumi; Katsukawa, Yukio; Matsuzaki, Keiichi;
   Ichimoto, Kiyoshi; Kano, Ryohei; Deluca, Edward E.; Lundquist,
   Loraine L.; Weber, Mark; Tarbell, Theodore D.; Shine, Richard A.;
   Sôma, Mitsuru; Tsuneta, Saku; Sakao, Taro; Minesugi, Kenji
Bibcode: 2007PASJ...59S.845S
Altcode: 2007arXiv0709.4098S
  To understand the physical mechanisms for activity and heating in
  the solar atmosphere, the magnetic coupling from the photosphere
  to the corona is an important piece of information from the Hinode
  observations, and therefore precise positional alignment is required
  among the data acquired by different telescopes. The Hinode spacecraft
  and its onboard telescopes were developed to allow us to investigate
  magnetic coupling with co-alignment accuracy better than 1". Using
  the Mercury transit observed on 2006 November 8 and co-alignment
  measurements regularly performed on a weekly basis, we have determined
  the information necessary for precise image co-alignment, and have
  confirmed that co-alignment better than 1" can be realized between
  Solar Optical Telescope (SOT) and X-Ray Telescope (XRT) with our
  baseline co-alignment method. This paper presents results from the
  calibration for precise co-alignment of CCD images from SOT and XRT.

Title: Hinode Observations of a Vector Magnetic Field Change
    Associated with a Flare on 2006 December 13
Authors: Kubo, Masahito; Yokoyama, Takaaki; Katsukawa, Yukio; Lites,
   Bruce; Tsuneta, Saku; Suematsu, Yoshinori; Ichimoto, Kiyoshi; Shimizu,
   Toshifumi; Nagata, Shin'ichi; Tarbell, Theodore D.; Shine, Richard A.;
   Title, Alan M.; Elmore David
Bibcode: 2007PASJ...59S.779K
Altcode: 2007arXiv0709.2397K
  Continuous observations of the flare productive active region 10930
  were successfully carried out with the Solar Optical Telescope aboard
  the Hinode spacecraft during 2006 December 6 to 19. We focused on the
  evolution of photospheric magnetic fields in this active region, and the
  magnetic field properties at the site of the X3.4 class flare, using
  a time series of vector field maps with high spatial resolution. The
  X3.4 class flare occurred on 2006 December 13 at the apparent
  collision site between the large, opposite polarity umbrae. Elongated
  magnetic structures with alternatingly positive and negative polarities
  resulting from flux emergence appeared one day before the flare in the
  collision site penumbra. Subsequently, the polarity inversion line
  at the collision site became very complicated. The number of bright
  loops in CaII H increased during the formation of these elongated
  magnetic structures. Flare ribbons and bright loops evolved along
  the polarity inversion line and one footpoint of the bright loop was
  located in a region having a large departure of the field azimuth angle
  with respect to its surroundings. SOT observations with high spatial
  resolution and high polarization precision revealed temporal change in
  the fine structure of magnetic fields at the flare site: some parts of
  the complicated polarity inversion line then disappeared, and in those
  regions the azimuth angle of the photospheric magnetic field changed by
  about 90°, becoming more spatially uniform within the collision site.

Title: The Analysis of Penumbral Fine Structure Using an Advanced
    Inversion Technique
Authors: Jurcák, Jan; Bellot Rubio, Luis; Ichimoto, Kiyoshi;
   Katsukawa, Yukio; Lites, Bruce; Nagata, Shin'ichi; Shimizu, Toshifumi;
   Suematsu, Yoshinori; Tarbell, Theodore D.; Title, Alan M.; Tsuneta,
   Saku
Bibcode: 2007PASJ...59S.601J
Altcode: 2007arXiv0707.1560J
  We present a method to study the penumbral fine structure using data
  obtained by the spectropolarimeter on board Hinode. For the first
  time, the penumbral filaments can be considered as being resolved in
  spectropolarimetric measurements. This enables us to use inversion
  codes with only one-component model atmospheres, and thus to assign
  the obtained stratifications of the plasma parameters directly to the
  penumbral fine structure. This approach was applied to the limb-side
  part of the penumbra in the active region NOAA10923. Preliminary results
  show a clear dependence of the plasma parameters on the continuum
  intensity in the inner penumbra, i.e., a weaker and horizontal magnetic
  field along with an increased line-of-sight velocity are found in the
  low layers of the bright filaments. The results in the mid penumbra
  are ambiguous, and future analyses are necessary to unveil the magnetic
  field structure and other plasma parameters there.

Title: Fine-Scale Structures of the Evershed Effect Observed by the
    Solar Optical Telescope aboard Hinode
Authors: Ichimoto, Kiyoshi; Shine, Richard A.; Lites, Bruce; Kubo,
   Masahito; Shimizu, Toshifumi; Suematsu, Yoshinori; Tsuneta, Saku;
   Katsukawa, Yukio; Tarbell, Theodore D.; Title, Alan M.; Nagata,
   Shin'ichi; Yokoyama, Takaaki; Shimojo, Masumi
Bibcode: 2007PASJ...59S.593I
Altcode:
  The small-scale structure of the Evershed effect is being studied
  using data obtained by the Spectropolarimeter and the Broadband Filter
  Imager of the Solar Optical Telescope aboard Hinode. We find that the
  Evershed flow starts at the leading edge of inwardly migrating bright
  penumbral grains, and turns to nearly a horizontal flow preferentially
  in the dark lanes of the penumbra. A number of small elongated regions
  that have an upward motion of ∼ 1kms<SUP>-1</SUP> are found in the
  deep photosphere distributed over the penumbra. They are cospatial
  with bright grains and have relatively horizontal magnetic fields. A
  number of patches having a strong downward motion associated with the
  opposite magnetic polarity from the sunspot are also found in the mid
  and outer penumbra. They could be identified as foot points of the
  Evershed flow channels, though the identification of individual pairs
  is not straightforward. Our results provide strong support for some
  recent findings from ground-based high-resolution observations, and
  are in general agreement with the well-known picture of the uncombed
  structure of the penumbra, in which the penumbrae consist of rising
  flux tubes carrying nearly horizontal Evershed flows embedded in more
  vertical background magnetic fields.

Title: Flare Ribbons Observed with G-band and FeI 6302Å, Filters
    of the Solar Optical Telescope on Board Hinode
Authors: Isobe, Hiroaki; Kubo, Masahito; Minoshima, Takashi; Ichimoto,
   Kiyoshi; Katsukawa, Yukio; Tarbell, Theodore D.; Tsuneta, Saku; Berger,
   Thomas E.; Lites, Bruce; Nagata, Shin'ichi; Shimizu, Toshifumi; Shine,
   Richard A.; Suematsu, Yoshinori; Title, Alan M.
Bibcode: 2007PASJ...59S.807I
Altcode: 2007arXiv0711.3946I
  The Solar Optical Telescope (SOT) on board the Hinode satellite observed
  an X3.4 class flare on 2006 December 13. A typical two-ribbon structure
  was observed, not only in the chromospheric CaII H line, but also in
  the G-band and FeI 6302Å line. The high-resolution, seeing-free images
  achieved by SOT revealed, for the first time, sub-arcsec fine structures
  of the ``white light'' flare. The G-band flare ribbons on sunspot
  umbrae showed a sharp leading edge, followed by a diffuse inside,
  as well as a previously known core-halo structure. The underlying
  structures, such as umbral dots, penumbral filaments, and granules,
  were visible in the flare ribbons. Assuming that the sharp leading
  edge was directly heated by a particle beam and the diffuse parts were
  heated by radiative back-warming, we estimated the depth of the diffuse
  flare emission using an intensity profile of the flare ribbon. We found
  that the depth of the diffuse emission was about 100km or less from
  the height of the source of radiative back-warming. The flare ribbons
  were also visible in the Stokes-V images of FeI 6302Å, as a transient
  polarity reversal. This is probably related to a ``magnetic transient''
  reported in the literature. The intensity increase in Stokes-I images
  indicates that the FeI 6302Å line was significantly deformed by the
  flare, which may cause such a magnetic transient.

Title: Small-Scale Magnetic-Flux Emergence Observed with Hinode
    Solar Optical Telescope
Authors: Otsuji, Kenichi; Shibata, Kazunari; Kitai, Reizaburo; Ueno,
   Satoru; Nagata, Shin'ichi; Matsumoto, Takuma; Nakamura, Tahei;
   Watanabe, Hiroko; Tsuneta, Saku; Suematsu, Yoshinori; Ichimoto,
   Kiyoshi; Shimizu, Toshifumi; Katsukawa, Yukio; Tarbell, Theodore D.;
   Lites, Bruce; Shine, Richard A.; Title Alan M.
Bibcode: 2007PASJ...59S.649O
Altcode: 2007arXiv0709.3207O
  We observed small-scale magnetic-flux emergence in a sunspot moat region
  by the Solar Optical Telescope (SOT) aboard the Hinode satellite. We
  analyzed filtergram images observed at wavelengths of Fe 6302Å, G band,
  and CaII H. In Stokes I images of Fe 6302Å, emerging magnetic flux was
  recognized as dark lanes. In the G band, they showed to be their shapes
  almost the same as in Stokes I images. These magnetic fluxes appeared
  as dark filaments in CaII H images. Stokes V images of Fe 6302Å showed
  pairs of opposite polarities at footpoints of each filament. These
  magnetic concentrations were identified to correspond to bright points
  in G band/CaII H images. From an analysis of time-sliced diagrams, we
  derived the following properties of emerging flux, which are consistent
  with those of previous studies: (1) Two footpoints separate each other
  at a speed of 4.2kms<SUP>-1</SUP> during the initial phase of evolution,
  and decrease to about 1kms<SUP>-1</SUP> 10minutes later. (2) CaII H
  filaments appear almost simultaneously with the formation of dark lanes
  in Stokes I in an observational cadence of 2minutes. (3) The lifetime
  of the dark lanes in the Stokes I and G band is 8minutes, while that
  of Ca filament is 12minutes. An interesting phenomena was observed,
  that an emerging flux tube expanded laterally in the photosphere with a
  speed of 3.8kms<SUP>-1</SUP>. A discussion on the horizontal expansion
  of the flux tube is given with refernce to previous simulation studies.

Title: Observations of Sunspot Oscillations in G Band and CaII H
    Line with Solar Optical Telescope on Hinode
Authors: Nagashima, Kaori; Sekii, Takashi; Kosovichev, Alexander G.;
   Shibahashi, Hiromoto; Tsuneta, Saku; Ichimoto, Kiyoshi; Katsukawa,
   Yukio; Lites, Bruce; Nagata, Shin'ichi; Shimizu, Toshifumi; Shine,
   Richard A.; Suematsu, Yoshinori; Tarbell, Theodore D.; Title, Alan M.
Bibcode: 2007PASJ...59S.631N
Altcode: 2007arXiv0709.0569N
  Exploiting high-resolution observations made by the Solar Optical
  Telescope on board Hinode, we investigate the spatial distribution
  of the power spectral density of the oscillatory signal in and around
  the active region NOAA 10935. The G-band data show that in the umbra
  the oscillatory power is suppressed in all frequency ranges. On
  the other hand, in CaII H intensity maps oscillations in the umbra,
  so-called umbral flashes, are clearly seen with the power peaking around
  5.5mHz. The CaII H power distribution shows the enhanced elements with
  the spatial scale of the umbral flashes over most of the umbra, but
  there is a region with suppressed power at the center of the umbra. The
  origin and property of this node-like feature remain unexplained.

Title: Hinode SP Vector Magnetogram of AR10930 and Its
    Cross-Comparison with MDI
Authors: Moon, Yong-Jae; Kim, Yeon-Han; Park, Young-Deuk; Ichimoto,
   Kiyoshi; Sakurai, Takashi; Chae, Jongchul; Cho, Kyung Suk; Bong,
   Suchan; Suematsu, Yoshinori; Tsuneta, Saku; Katsukawa, Yukio; Shimojo,
   Masumi; Shimizu, Toshifumi; Shine, Richard A.; Tarbell, Theodore D.;
   Title, Alan M.; Lites, Bruce; Kubo, Masahito; Nagata, Shin'ichi;
   Yokoyama, Takaaki
Bibcode: 2007PASJ...59S.625M
Altcode:
  We present one Hinode Spectropolarimeter (SP) magnetogram of AR 10930
  that produced several major flares. The inversion from Stokes profiles
  to magnetic field vectors was made using the standard Milne-Eddington
  code. We successfully applied the Uniform Shear Method for resolving
  the 180° ambiguity to the magnetogram. The inversion gave very strong
  magnetic field strengths (near 4500 gauss) for a small portion of area
  in the umbra. Considering that the observed V-profile of 6301.5Å was
  well-fitted as well as a direct estimation of the Zeeman splitting
  results in 4300-4600 gauss, we think that the field strengths
  should not be far from the actual value. A cross-comparison of the
  Hinode SP and SOHO MDI high resolution flux densities shows that the
  MDI flux density could be significantly underestimated by about a
  factor of two. In addition, it has a serious negative correlation
  (the so-called Zeeman saturation effect) with the Hinode SP flux
  density for umbral regions. Finally, we could successfully obtain
  a recalibrated MDI magnetogram that has been corrected for the
  Zeeman saturation effect using not only a pair of MDI intensity and
  magnetogram data simultaneously observed, but also the relationship
  from the cross-comparison between the Hinode SP and MDI flux densities.

Title: Formation Process of a Light Bridge Revealed with the Hinode
    Solar Optical Telescope
Authors: Katsukawa, Yukio; Yokoyama, Takaaki; Berger, Thomas E.;
   Ichimoto, Kiyoshi; Kubo, Masahito; Lites, Bruce; Nagata, Shin'ichi;
   Shimizu, Toshifumi; Shine, Richard A.; Suematsu, Yoshinori; Tarbell,
   Theodore D.; Title, Alan M.; Tsuneta, Saku
Bibcode: 2007PASJ...59S.577K
Altcode: 2007arXiv0709.2527K
  The Solar Optical Telescope (SOT) on-board Hinode successfully and
  continuously observed the formation process of a light bridge in a
  matured sunspot of the NOAA active region 10923 for several days with
  high spatial resolution. During its formation, many umbral dots were
  observed to be emerging from the leading edges of penumbral filaments,
  and rapidly intruding into the umbra. The precursor of the light bridge
  formation was also identified as a relatively slow inward motion of
  the umbral dots, which emerged not near the penumbra, but inside the
  umbra. The spectro-polarimeter on SOT provided physical conditions in
  the photosphere around the umbral dots and the light bridges. We found
  that the light bridges and the umbral dots had significantly weaker
  magnetic fields associated with upflows relative to the core of the
  umbra, which implies that there was hot gas with weak field strength
  penetrating from the subphotosphere to near the visible surface inside
  those structures. There needs to be a mechanism to drive the inward
  motion of the hot gas along the light bridges. We suggest that the
  emergence and the inward motion are triggered by a buoyant penumbral
  flux tube as well as subphotospheric flow crossing the sunspot.

Title: Umbral Fine Structures in Sunspots Observed with Hinode Solar
    Optical Telescope
Authors: Kitai, Reizaburo; Watanabe, Hiroko; Nakamura, Tahei; Otsuji,
   Ken-ichi; Matsumoto, Takuma; UeNo, Satoru; Nagata, Shin'ichi; Shibata,
   Kazunari; Muller, Richard; Ichimoto, Kiyoshi; Tsuneta, Saku; Suematsu,
   Yoshinori; Katsukawa, Yukio; Shimizu, Toshifumi; Tarbell, Theodore D.;
   Shine, Richard A.; Title, Alan M.; Lites, Bruce
Bibcode: 2007PASJ...59S.585K
Altcode: 2007arXiv0711.3266K
  A high resolution imaging observation of a sunspot umbra was made with
  the Hinode Solar Optical Telescope. Filtergrams at wavelengths of the
  blue and green continua were taken during three consecutive days. The
  umbra consisted of a dark core region, several diffuse components,
  and numerous umbral dots. We derived basic properties of umbral dots
  (UDs), especially their temperatures, lifetimes, proper motions,
  spatial distribution, and morphological evolution. The brightness
  of UDs is confirmed to depend on the brightness of their surrounding
  background. Several UDs show fission and fusion. Thanks to the stable
  condition of the space observation, we could for the first time follow
  the temporal behavior of these events. The derived properties of the
  internal structure of the umbra are discussed from the viewpoint of
  magnetoconvection in a strong magnetic field.

Title: On Connecting the Dynamics of the Chromosphere and Transition
    Region with Hinode SOT and EIS
Authors: Hansteen, Viggo H.; de Pontieu, Bart; Carlsson, Mats;
   McIntosh, Scott; Watanabe, Tetsuya; Warren, Harry P.; Harra, Louise K.;
   Hara, Hirohisa; Tarbell, Theodore D.; Shine, Dick; Title, Alan M.;
   Schrijver, Carolus J.; Tsuneta, Saku; Katsukawa, Yukio; Ichimoto,
   Kiyoshi; Suematsu, Yoshinori; Shimizu, Toshifumi
Bibcode: 2007PASJ...59S.699H
Altcode: 2007arXiv0711.0487H
  We use coordinated Hinode SOT/EIS observations that include
  high-resolution magnetograms, chromospheric, and transition region
  (TR) imaging, and TR/coronal spectra in a first test to study how
  the dynamics of the TR are driven by the highly dynamic photospheric
  magnetic fields and the ubiquitous chromospheric waves. Initial
  analysis shows that these connections are quite subtle and require a
  combination of techniques including magnetic field extrapolations,
  frequency-filtered time-series, and comparisons with synthetic
  chromospheric and TR images from advanced 3D numerical simulations. As a
  first result, we find signatures of magnetic flux emergence as well as
  3 and 5mHz wave power above regions of enhanced photospheric magnetic
  field in both chromospheric, transition region, and coronal emission.

Title: Can High Frequency Acoustic Waves Heat the Quiet Sun
    Chromosphere?
Authors: Carlsson, Mats; Hansteen, Viggo H.; de Pontieu, Bart;
   McIntosh, Scott; Tarbell, Theodore D.; Shine, Dick; Tsuneta, Saku;
   Katsukawa, Yukio; Ichimoto, Kiyoshi; Suematsu, Yoshinori; Shimizu,
   Toshifumi; Nagata, Shin'ichi
Bibcode: 2007PASJ...59S.663C
Altcode: 2007arXiv0709.3462C
  We use Hinode/SOT Ca II H-line and blue continuum broadband observations
  to study the presence and power of high frequency acoustic waves at
  high spatial resolution. We find that there is no dominant power at
  small spatial scales; the integrated power using the full resolution of
  Hinode (0.05'' pixels, 0.16'' resolution) is larger than the power in
  the data degraded to 0.5'' pixels (TRACE pixel size) by only a factor
  of 1.2. At 20 mHz the ratio is 1.6. Combining this result with the
  estimates of the acoustic flux based on TRACE data of Fossum &amp;
  Carlsson (2006), we conclude that the total energy flux in acoustic
  waves of frequency 5-40 mHz entering the internetwork chromosphere of
  the quiet Sun is less than 800 W m$^{-2}$, inadequate to balance the
  radiative losses in a static chromosphere by a factor of five.

Title: Formation of Moving Magnetic Features and Penumbral Magnetic
    Fields with Hinode/SOT
Authors: Kubo, Masahito; Ichimoto, Kiyoshi; Shimizu, Toshifumi;
   Tsuneta, Saku; Suematsu, Yoshinori; Katsukawa, Yukio; Nagata,
   Shin'ichi; Tarbell, Theodore D.; Shine, Richard A.; Title, Alan M.;
   Frank, Zoe A.; Lites, Bruce; Elmore, David
Bibcode: 2007PASJ...59S.607K
Altcode: 2007arXiv0709.1853K
  Vector magnetic fields of moving magnetic features (MMFs) were well
  observed with the Solar Optical Telescope (SOT) aboard the Hinode
  satellite. We focused on the evolution of three MMFs with the SOT in
  this study. We found that an MMF having relatively vertical fields
  with the same polarity as the sunspot was detached from the penumbra
  around the granules appearing in the outer penumbra. This suggests
  that granular motions in the outer penumbra are responsible for
  disintegration of the sunspot. Two MMFs with polarity opposite to
  the sunspot are located around the outer edge of horizontal fields
  extending from the penumbra. This is evidence that the MMFs with
  polarity opposite to the sunspot are the prolongation of penumbral
  horizontal fields. Redshifts larger than the sonic velocity in the
  photosphere are detected for some of the MMFs with polarity opposite
  to the sunspot.

Title: A Tale of Two Spicules: The Impact of Spicules on the Magnetic
    Chromosphere
Authors: de Pontieu, Bart; McIntosh, Scott; Hansteen, Viggo H.;
   Carlsson, Mats; Schrijver, Carolus J.; Tarbell, Theodore D.; Title,
   Alan M.; Shine, Richard A.; Suematsu, Yoshinori; Tsuneta, Saku;
   Katsukawa, Yukio; Ichimoto, Kiyoshi; Shimizu, Toshifumi; Nagata,
   Shin'ichi
Bibcode: 2007PASJ...59S.655D
Altcode: 2007arXiv0710.2934D
  We use high-resolution observations of the Sun in CaIIH (3968Å)
  from the Solar Optical Telescope on Hinode to show that there are
  at least two types of spicules that dominate the structure of the
  magnetic solar chromosphere. Both types are tied to the relentless
  magnetoconvective driving in the photosphere, but have very different
  dynamic properties. ``Type-I'' spicules are driven by shock waves
  that form when global oscillations and convective flows leak into
  the upper atmosphere along magnetic field lines on 3--7minute
  timescales. ``Type-II'' spicules are much more dynamic: they form
  rapidly (in ∼ 10s), are very thin (≤ 200 km wide), have lifetimes
  of 10-150s (at any one height), and seem to be rapidly heated to
  (at least) transition region temperatures, sending material through
  the chromosphere at speeds of order 50--150kms<SUP>-1</SUP>. The
  properties of Type II spicules suggest a formation process that is
  a consequence of magnetic reconnection, typically in the vicinity
  of magnetic flux concentrations in plage and network. Both types of
  spicules are observed to carry Alfvén waves with significant amplitudes
  of order 20kms<SUP>-1</SUP>.

Title: Estimate on SOT Light Level in Flight with Throughput
    Measurements in SOT Sun Tests
Authors: Shimizu, T.; Kubo, M.; Tarbell, T. D.; Berger, T. E.;
   Suematsu, Y.; Ichimoto, K.; Katsukawa, Y.; Miyashita, M.; Noguchi,
   M.; Nakagiri, M.; Tsuneta, S.; Elmore, D. F.; Lites, B. W.
Bibcode: 2007ASPC..369...51S
Altcode:
  The SOT (Solar Optical Telescope, e.g., Shimizu 2004) optical
  system consists of 50cm-aperture optical telescope (OTA) and focal
  plane instrument (FPP). The solar light into the telescope penetrates
  through many optical elements located in OTA and FPP before illuminating
  CCDs. Natural solar light was fed to the integrated SOT in sun tests for
  verifying various optical aspects including the confirmation of photon
  throughput. CCD exposures provide the number of photons accumulated
  in an exposure duration with a clean-room test condition. To estimate
  the absolute intensity of the solar light at the telescope entrance
  in the clean-room test condition, we developed a pinhole-PSD sensor
  for simultaneous monitoring the solar light outside the clean room
  and measured the transmission of light through two flat mirrors of
  the heliostat and clean-room entrance window glass as a function of
  wavelength. The PSD sensor was pre-calibrated with continuous monitoring
  the solar light in a day long under a clear constant sky condition,
  determining the earth atmospheric attenuation and the PSD output for
  the solar light on orbit. These throughput measurements have provided
  an estimate on photon throughput for the SOT flight model. The results
  confirm suitable number of photons without saturation for proper CCD
  exposures in flight.

Title: Supersonic Downflows in the Photosphere Discovered in Sunspot
    Moat Regions
Authors: Shimizu, T.; Martinez-Pillet, V.; Collados, M.; Ruiz-Cobo,
   B.; Centeno, R.; Beck, C.; Katsukawa, Y.
Bibcode: 2007ASPC..369..113S
Altcode:
  This paper reports on our new findings from the International
  Time Program observations at the Canaries islands, Spain, in July
  2005. We have found small-scale photospheric events with extremely
  red-shifted Stokes V signals in sunspot moat regions. A preliminary
  estimate of the physical conditions for an observed Stokes V profile
  indicates the presence of a downward motion with a supersonic speed
  in the order of 10 km/s. With the currently evaluated observational
  information, we interprete the supersonic flows as downward motion from
  magnetic reconnection occurring at the upper chromosphere or lower
  photosphere. With coordinated observations of the Solar-B onboard
  telescopes, Stokes measurements by the SOT spectro-polarimeter would
  give new information for further understanding the nature of these
  events with strongly red-shifted Stokes V, and for discussing the
  physical conditions involving in possible magnetic reconnections in
  the lower solar atmosphere.

Title: Calibration of the SOT Polarization
Authors: Ichimoto, K.; Suematsu, Y.; Shimizu, T.; Katsukawa, Y.;
   Noguchi, M.; Nakagiri, M.; Miyashita, M.; Tsuneta, S.; Tarbell, T. D.;
   Shine, R. A.; Hoffmann, C. M.; Cruz, T.; Lites, B. W.; Elmore, D. F.
Bibcode: 2007ASPC..369...39I
Altcode:
  Calibration of SOT polarization property was performed using natural
  sunlight and well calibrated sheet polarizer (linear and circular)
  placed on the entrance of the telescope. The polarimeter response
  matrices were determined for the spectropolarimeter (SP) and the
  narrowband filter imager (NFI), and it is shown that they are well
  behave as predicted and constant over the field of view. The crosstalk
  between I,Q,U,V will be suppressed to the negligible level at the
  photometric accuracy of 10^{-3} after the calibration with the obtained
  matrices. The sensitivity of SOT on linear and circular polarizations
  at each wavelength observed by NFI are also obtained.

Title: Calibration of SOT Dopplergrams
Authors: Katsukawa, Y.; Ichimoto, K.; Sekii, T.; Suematsu, Y.; Tsuneta,
   S.; Shine, R. A.; Tarbell, T. D.
Bibcode: 2007ASPC..369...43K
Altcode:
  Narrow-band Filter Imager on SOT provides Dopplergrams (DGs) which
  are images of Doppler (line- of-sight) velocities. Observations with
  DGs are critically important in studies of photospheric dynamics and
  helioseismology. The primary photospheric line used for DGs is Fe I 5576
  Å which is a line insensitive to Zeeman effect. We made a calibration
  function for the 5576 Å DGs to get actual Doppler velocities from
  velocity indexes using an atlas spectrum and simulated transmission
  profiles for the tunable filter (TF) on SOT. Using data sets taken
  in the natural sun-light test, we quantitatively evaluated accuracy
  of the DGs by comparing the rotational speed of the Sun measured
  with DGs with the expected one. There was a little systematic error
  in the velocity obtained by SOT, but the error was less than 20 %
  of the predicted velocities.

Title: Examinations of the Relative Alignment of the Instruments
    on SOT
Authors: Okamoto, T. J.; Katsukawa, Y.; Shimizu, T.; Ichimoto, K.;
   Suematsu, Y.; Tsuneta, S.; Tarbell, T. D.
Bibcode: 2007ASPC..369...47O
Altcode:
  We report the results of the examination about the relative alignment
  among the instruments on SOT. We employ a test data set obtained in the
  natural sun-light test in May 2005, which has had a grid pattern over
  the entire FOV. SOT has the filtergraph (FG) and the spectro-polarimeter
  (SP). The FG consists of six broadband filter imagers (BFI) and six
  narrowband filter imagers (NFI). We examined the displacements among
  the images taken with different filters to an accuracy of better than
  0.1 pixel corresponding to 0.02''. It is important to know relative
  displacements and plate scales of these instruments for accurate
  alignment of observational data. We note that the values measured in
  our work are relative and it is needed to decide the absolute values
  with another way.

Title: Vector Spectropolarimetry of Dark-cored Penumbral Filaments
    with Hinode
Authors: Bellot Rubio, L. R.; Tsuneta, S.; Ichimoto, K.; Katsukawa,
   Y.; Lites, B. W.; Nagata, S.; Shimizu, T.; Shine, R. A.; Suematsu,
   Y.; Tarbell, T. D.; Title, A. M.; del Toro Iniesta, J. C.
Bibcode: 2007ApJ...668L..91B
Altcode: 2007arXiv0708.2791B
  We present spectropolarimetric measurements of dark-cored penumbral
  filaments taken with Hinode at a resolution of 0.3". Our observations
  demonstrate that dark-cored filaments are more prominent in polarized
  light than in continuum intensity. Far from disk center, the Stokes
  profiles emerging from these structures are very asymmetric and show
  evidence for magnetic fields of different inclinations along the
  line of sight, together with strong Evershed flows of at least 6-7 km
  s<SUP>-1</SUP>. In sunspots closer to disk center, dark-cored penumbral
  filaments exhibit regular Stokes profiles with little asymmetries due
  to the vanishing line-of-sight component of the horizontal Evershed
  flow. An inversion of the observed spectra indicates that the magnetic
  field is weaker and more inclined in the dark cores as compared with
  the surrounding bright structures. This is compatible with the idea
  that dark-cored filaments are the manifestation of flux tubes carrying
  hot Evershed flows.

Title: Observational Analysis of the Relation between Coronal Loop
    Heating and Photospheric Magnetic Fields
Authors: Katsukawa, Y.
Bibcode: 2007ASPC..369..287K
Altcode:
  The solar corona and the photosphere are linked through magnetic
  field lines, and heating energy is supposed to be supplied from the
  footpoints of each coronal loop along magnetic field lines. Thus it is
  important to examine properties of photospheric magnetic fields at the
  footpoints of the coronal loops in order to understand heating of the
  coronal loops. We performed simultaneous observations of photospheric
  magnetic properties and coronal loop structures using the ground based
  telescopes and Transition Region And Coronal Explorer (TRACE). Footpoint
  locations were identified in the TRACE images, and the structure in
  the photosphere was examined by Advanced Stokes Polarimeter (ASP) or
  Dutch Open Telescope (DOT). Most of the coronal loops emanating from
  a sunspot had their footpoints around the boundary between the umbra
  and the penumbra. Furthermore, bright loops were revealed to have
  their footpoints at the locations where there was highly interlaced
  magnetic configuration. We observed fragmentation of an umbra and
  formation of a light bridge in decaying sunspots, and found possible
  association between such phenomena in the decaying spots and the coronal
  loops. These observational results suggest that spatial fluctuation
  of magnetic fields forms current sheets at the base of the corona,
  resulting in heating of the coronal loops.

Title: Relationships between magnetic foot points and G-band bright
    structures
Authors: Ishikawa, R.; Tsuneta, S.; Kitakoshi, Y.; Katsukawa, Y.;
   Bonet, J. A.; Vargas Domínguez, S.; Rouppe van der Voort, L. H. M.;
   Sakamoto, Y.; Ebisuzaki, T.
Bibcode: 2007A&A...472..911I
Altcode: 2008arXiv0802.1765I
  Aims:Magnetic elements are thought to be described by flux tube models,
  and are well reproduced by MHD simulations. However, these simulations
  are only partially constrained by observations. We observationally
  investigate the relationship between G-band bright points and magnetic
  structures to clarify conditions, which make magnetic structures
  bright in G-band. <BR />Methods: The G-band filtergrams together with
  magnetograms and dopplergrams were taken for a plage region covered
  by abnormal granules as well as ubiquitous G-band bright points,
  using the Swedish 1-m Solar Telescope (SST) under very good seeing
  conditions. <BR />Results: High magnetic flux density regions are
  not necessarily associated with G-band bright points. We refer to the
  observed extended areas with high magnetic flux density as magnetic
  islands to separate them from magnetic elements. We discover that G-band
  bright points tend to be located near the boundary of such magnetic
  islands. The concentration of G-band bright points decreases with inward
  distance from the boundary of the magnetic islands. Moreover, G-band
  bright points are preferentially located where magnetic flux density is
  higher, given the same distance from the boundary. There are some bright
  points located far inside the magnetic islands. Such bright points have
  higher minimum magnetic flux density at the larger inward distance from
  the boundary. Convective velocity is apparently reduced for such high
  magnetic flux density regions regardless of whether they are populated
  by G-band bright points or not. The magnetic islands are surrounded by
  downflows. <BR />Conclusions: These results suggest that high magnetic
  flux density, as well as efficient heat transport from the sides or
  beneath, are required to make magnetic elements bright in G-band.

Title: Emergence of Small-Scale Magnetic Loops in the Quiet-Sun
    Internetwork
Authors: Centeno, R.; Socas-Navarro, H.; Lites, B.; Kubo, M.; Frank,
   Z.; Shine, R.; Tarbell, T.; Title, A.; Ichimoto, K.; Tsuneta, S.;
   Katsukawa, Y.; Suematsu, Y.; Shimizu, T.; Nagata, S.
Bibcode: 2007ApJ...666L.137C
Altcode: 2007arXiv0708.0844C
  We study the emergence of magnetic flux at very small spatial
  scales (less than 2") in the quiet-Sun internetwork. To this aim,
  a time series of spectropolarimetric maps was taken at disk center
  using the instrument SP/SOT on board Hinode. The LTE inversion of
  the full Stokes vector measured in the Fe I 6301 and 6302 Å lines
  allows us to retrieve the magnetic flux and topology in the region
  of study. In the example presented here, the magnetic flux emerges
  within a granular structure. The horizontal magnetic field appears
  prior to any significant amount of vertical field. As time goes on,
  the traces of the horizontal field disappear, while the vertical dipoles
  drift-carried by the plasma motions-toward the surrounding intergranular
  lanes. These events take place within typical granulation timescales.

Title: Chromospheric Micro-jets Discovered Above Sunspot Penumbrae
Authors: Katsukawa, Yukio; Tsuneta, S.; Suematsu, Y.; Ichimoto, K.;
   Shimizu, T.; Kubo, M.; Nagata, S.; Berger, T.; Tarbell, T.; Shine,
   R.; Title, A.
Bibcode: 2007AAS...210.9413K
Altcode: 2007BAAS...39..219K
  The Solar Optical Telescope (SOT) aboard HINODE allows us to observe
  dynamical activities in the solar photosphere and the chromosphere
  with high and stable image quality of 0.2 arcseconds. This superior
  performance of SOT provides new findings of fine-scale transient
  activities occurring in the chromosphere. In this paper, we report
  discovery of fine-scale jet-like phenomena ubiquitously observed
  above sunspot penumbrae. The jets are identified in image sequences
  of a sunspot taken through a Ca II H line filter at 3968A. The Ca II
  H line is sensitive to about 10^4 K plasma in the chromosphere. <P
  />Their length is typically between 3000 and 10000km, and their
  width is smaller than 500km. It is notable that their lifetime
  is shorter than 1 minute. Those small spatial and temporal scale
  possibly makes it difficult to identify the phenomena in existing
  ground-based observations. The jets are easily identified when a
  sunspot is located far from the disk center, and motion of the bright
  features suggests that mass is erupted from lower chromosphere to upper
  atmosphere. Velocities of the motion are estimated to be 50 to 100 km/s
  from their lateral motion of intensity patterns. The velocities are much
  faster than sound speeds in the chromosphere. A possible cause of such
  high-speed jets is magnetic reconnection at the lower chromosphere
  resulted from fluted magnetic configuration in penumbrae which is
  suggested by vector magnetic field measurements in the photosphere.

Title: Hinode Data Calibration For Precise Image Co-alignment:
    XRT vs. SOT
Authors: Shimizu, Toshifumi; DeLuca, E. E.; Lundquist, L.; Sakao,
   T.; Kubo, M.; Narukage, N.; Kano, R.; Katsukawa, Y.; Ichimoto, K.;
   Suematsu, Y.; Tsuneta, S.; Tarbell, T.; Shine, D.; Hinode Team
Bibcode: 2007AAS...210.9417S
Altcode: 2007BAAS...39Q.220S
  From late October in 2006, Hinode solar optical telescope (SOT) has
  started to produce series of 0.2-0.3 arcsec visible-light images,
  revealing dynamical behaviors of solar magnetic fields on the
  solar surface. Simultaneously, Hinode X-ray telescope (XRT) has been
  providing 1 arcsec resolution X-ray images of the solar corona, giving
  the location of heating and dynamics occuring in the corona. Precise
  image co-alignment of SOT data on XRT data with sub-arcsec accuracy is
  required to provide new information regarding connecting the corona to
  the photosphere. This presentation will give an introduction of Hinode
  between-telescopes' image co-alignment to SPD participants. For active
  region observations with sunspots, sunspots can be used as fiducial to
  co-align the data from the two telescopes each other. Satellite jitter
  in order of 1 arcsec or less is included in the series of XRT data,
  whereas image stabilization system (correlation tracker) removes the
  satellite jitter from the series of SOT images. Telescope pointings show
  orbital variation in order of a few arcsec, which can be well predicted
  from Hinode orbit information. Modeling co-alignment is under study
  and it is the only precise method for quiet Sun and limb observations.

Title: Magnetic Patches in Internetwork Quiet Sun
Authors: De Wijn, Alfred; Lites, B.; Berger, T.; Shine, R.; Title,
   A.; Katsukawa, Y.; Tsuneta, S.; Suematsu, Y.; Shimizu, T.; Hinode Team
Bibcode: 2007AAS...210.9412D
Altcode: 2007BAAS...39Q.219D
  We study strong flux elements in the quiet sun in the context of
  the nature of quiet-sun magnetism, its coupling to chromospheric,
  transition-region and coronal fields, and the nature of a local
  turbulent dynamo. Strong, kilogauss flux elements show up intermittently
  as small bright points in G-band and Ca II H images. Although
  bright points have been extensively studied in the magnetic network,
  internetwork magnetism has only come under scrutiny in recent years. A
  full spectrum of field strengths seems to be ubiquitously present in
  the internetwork at small spatial scales, with the stronger elements
  residing in intergranular lanes. De Wijn et al. (2005) found that bright
  points in quiet sun internetwork areas appear recurrently with varying
  intensity and horizontal motion within long-lived patches that outline
  cell patterns on mesogranular scales. They estimate that the "magnetic
  patches" have a mean lifetime of nine hours, much longer than granular
  timescales. We use multi-hour sequences of G-band and Ca II H images
  as well as magnetograms recorded by the Hinode satellite to follow up
  on their results. The larger field of view, the longer sequences, the
  addition of magnetograms, and the absence of atmospheric seeing allows
  us to better constrain the patch lifetime, to provide much improved
  statistics on IBP lifetime, to compare IBPs to network bright points,
  and to study field polarity of IBPs in patches and between nearby
  patches. <P />Hinode is an international project supported by JAXA,
  NASA, PPARC and ESA. We are grateful to the Hinode team for all their
  efforts in the design, build and operation of the mission.

Title: Hinode/SOT Observations Of Apparent "Thermal Plume" Motions
    In A Solar Prominence
Authors: Berger, Thomas; Tarbell, T.; Slater, G.; Tsuneta, S.;
   Suematsu, Y.; Ichimoto, K.; Katsukawa, Y.; Shimizu, T.; Kubo, M.;
   Nagata, S.
Bibcode: 2007AAS...210.9433B
Altcode: 2007BAAS...39..222B
  We present 396.8 nm Ca II H-line observations of a large
  hedgerow, or "sheet", prominence seen on the solar western limb
  on 30-November-2006. The 16 second cadence observations show dark
  channels rising vertically at speeds of approximately 10 km/sec to
  heights of about 15 Mm above the limb. Many of the motions end in
  vortical overturning near the top of the sheet . Bright downflows of
  similar speed are also seen within the sheet, often in association
  with a dark channel that has risen to the top of the sheet. The dark
  channels are suggestive of hot material rising in thermal plumes
  within the prominence sheet. Similarly, the bright material motions
  appear to be density enhanced regions of turbulent downflow. Current
  models of sheet prominences do not include the observed dynamics. In
  these models, the prominence plasma is in a low-beta state and is
  constrained to move only along magnetic field lines. However the
  motions observed here are extremely complex, implying either that the
  magnetic field lines are undergoing turbulent motion, thus tangling
  and reconnecting constantly, or that the plasma is not constrained
  by the field and is in a high-beta convective state. We measure the
  motion of several representative "plumes" and downflows, estimate the
  density and temperature of the prominence plasma, and suggest several
  avenues for further investigation. <P />This work was supported by
  NASA under the Hinode/SOT contract NNM07AA01C.

Title: High Resolution Observation of Spicules in Ca II H with
    Hinode/SOT
Authors: Suematsu, Yoshinori; Katsukawa, Y.; Ichimoto, K.; Tsuneta, S.;
   Okamoto, T.; Nagata, S.; Shimizu, T.; Tarbell, T.; Shine, R.; Title, A.
Bibcode: 2007AAS...210.9411S
Altcode: 2007BAAS...39..219S
  High cadence observation with a Ca II H broadband filtergraph
  (passband of 0.25 nm) of the Solar Optical Telescope (SOT) aboard
  HINODE has revealed dynamical nature of solar limb spicules. Thanks to a
  diffraction-limited and low-scattered light property of the instrument,
  we can track the detailed evolution of individual spicules for the first
  time with a spatial resolution of 0.2 arcsec. The spicules in Ca II
  H are typically several arcsec tall and have multi-thread structure;
  each threads are a few tenth of arcsec wide. It should be stressed
  that most spicules do not show a simple up-and-down motion along a
  rigid path line. They start with bright structure emanating from Ca II
  H bright region, get widen and diffused with time and ascent, showing
  expansion with lateral or even helical motion in tall events. Small and
  short lived spicules tend to fade out after ascent. We will present
  new findings of spicule dynamics in different magnetic environments
  and discuss about long standing controversy of its motion and evolution.

Title: Hinode/SOT Observation of Fine Structure of the Evershed Flow
Authors: Ichimoto, Kiyoshi; Suematsu, Y.; Tsuneta, S.; Katsukawa, Y.;
   Shimojo, M.; Kubo, M.; Shimizu, T.; Shine, R.; Tarbell, T.; Title,
   A.; Lites, B.; Elmore, D.; Yokoyama, T.; Nagaka, S.
Bibcode: 2007AAS...210.9408I
Altcode: 2007BAAS...39..218I
  Small scale structure of the Evershed effect was studied using the
  Spectropolarimeter (SP) and Broadband Filter Imager (BFI) of SOT aboard
  Hinode. SP maps and high cadence continuum images of BFI coverting
  entire sunspots are used to investigate the spatial distribution of
  the flow field, brightness and magnetic fields. It is revealed that the
  Evershed flow starts at the front edge of inwardly migrating penumbral
  grains with an upward velocity component and turns to nearly holizontal
  flow preferentially in dark lanes (or dark core of filaments) of the
  penumbra. Our results are in general agreement with the well known
  uncombed penumbral concept in which the Evershed flow takes place
  in nearly holizontal field channels. We discovered a number of tiny
  elongated regions in deep photosphere in which there is an obvious
  upward motion of 1-1.5km/s distributing over the penumbra. <P />They
  could be identified as the 'foot points' of the individual Evershed
  flow channels. Cross-correlation among the flow speed, intensity,
  magnetic field strength and inclination, and distribution of string
  down flows in and around the penumbra will also be discussed.

Title: On the Moat-Penumbra Relation
Authors: Vargas Domínguez, S.; Bonet, J. A.; Martínez Pillet, V.;
   Katsukawa, Y.; Kitakoshi, Y.; Rouppe van der Voort, L.
Bibcode: 2007ApJ...660L.165V
Altcode: 2007astro.ph..2713V
  Proper motions in a sunspot group with a δ-configuration and close to
  the solar disk center have been studied by employing local correlation
  tracking techniques. The analysis is based on a more than 1 hr time
  series of G-band images. Radial outflows with a mean speed of 0.67
  km s<SUP>-1</SUP> have been detected around the spots, the well-known
  sunspots moats. However, these outflows are not found in those umbral
  core sides without penumbra. Moreover, moat flows are only found
  in those sides of penumbrae located in the direction marked by the
  penumbral filaments. Penumbral sides perpendicular to them show no
  moat flow. These results strongly suggest a relation between the
  moat flow and the well-known, filament-aligned Evershed flow. The
  standard picture of a moat flow originating from a blocking of the
  upward propagation of heat is discussed in some detail.

Title: Continuous Upflow of Plasmas at the Edge of an Active Region
    as Revealed by the X-ray Telescope (XRT) aboard Hinode
Authors: Sakao, Taro; Kano, R.; Narukage, N.; Kotoku, J.; Bando, T.;
   DeLuca, E. E.; Lundquist, L. L.; Golub, L.; Kubo, M.; Katsukawa, Y.;
   Tsuneta, S.; Hara, H.; Matsuzaki, K.; Shimojo, M.; Shibasaki, K.;
   Shimizu, T.; Nakatani, I.
Bibcode: 2007AAS...210.7205S
Altcode: 2007BAAS...39Q.179S
  We present X-ray imaging observations with Hinode X-Ray Telescope (XRT)
  of an active region NOAA AR 10942 made in the period of 20-22 February
  2007. A prominent feature that drew our particular attention is that
  there revealed continuous upflow of soft-X-ray-emitting plasmas along
  apparently-open field lines towards the outer corona emanating from the
  edge of the active region. <P />The field lines are originated from
  an ensamble of small spots of following polarity, and are located at
  a border between the active region and an adjacent equatorial coronal
  hole(s) located to the east. The upflow was observed to be continuous
  throughout the three days of observation intervals with projected
  velocity of 140 km/s, accompanied with undulating motion of the field
  lines. <P />We assert that these upflowing plasmas would be a possible
  source of slow solar wind material, which supports a foresighted
  notion which grew out of interplanetary scintillation observations
  that slow solar wind most likely has its origin in the vicinity of
  active regions with large flux expansion (Kojima et al. 1999). <P />A
  preliminaty analysis indicates that the temperature of the upflowing
  material near the base of the field lines is 1.3 MK with number density
  of 2 × 10<SUP>9 </SUP>/cm<SUP>3</SUP>. Assuming that all the material
  is to escape to the interplanetary space, this leads to a mass loss
  rate of 2 × 10<SUP>11</SUP> g/s which amounts to a good fraction of
  the total mass loss rate for solar wind. It is noteworthy that, even
  apart from this unique upflow, we see continuous (up)flows of plasmas
  anywhere around (surrounding) the active region. <P />Details of the
  upflow will be presented and their possible implication to slow solar
  wind discussed.

Title: Magnetic Flux Emergence In The Quiet Sun Photosphere
Authors: Centeno, Rebecca; Lites, B.; Socas-Navarro, H.; Frank,
   Z.; Shine, R.; Tarbell, T.; Title, A.; Ichimoto, K.; Tsuneta, S.;
   Katsukawa, Y.; Suematsu, Y.; Kubo, M.; Shimizu, T.
Bibcode: 2007AAS...210.9406C
Altcode: 2007BAAS...39..218C
  We study the emergence of magnetic flux at very small spacial scales
  (less than 1 arcsec) in the quiet Sun internetwork. To this aim, several
  time series of spectropolarimetric maps were taken at disk center using
  the instrument SP/SOT on board Hinode. The LTE inversion of the full
  Stokes vector measured in the Fe I 6301 and 6302 lines will allow us
  to retrieve the magnetic flux and topology in the region of study. We
  find that the magnetic flux emerges typically within the granular
  structures. In many cases, the horizontal magnetic field appears
  prior to any significant amount of vertical field. As time goes on,
  the traces of the horizontal field dissapear while the the vertical
  dipoles drift -carried by the plasma motions- towards the surrounding
  intergranular lanes. Sometimes they stay trapped there for a while
  but they eventually either disappear by disgregation/cancelation
  or agregate to other magnetic field concentrations giving rise to
  larger flux elements. The time scale of these events is of the order
  of 10-20 minutes.

Title: Formation of Moving Magnetic Features and Penumbral Magnetic
    Fields
Authors: Kubo, Masahito; Ichimoto, K.; Shimizu, T.; Tsuneta, S.;
   Suematsu, Y.; Katsukawa, Y.; Nagata, S.; Lites, B. W.; Frank, Z.;
   Tarbell, T. D.; Shine, R. A.; Title, A. M.
Bibcode: 2007AAS...210.9410K
Altcode: 2007BAAS...39..218K
  We investigate the formation process of Moving Magnetic Features
  (MMFs) observed with Hinode/SOT. Moving magnetic features are small
  magnetic elements moving outward in the moat region surrounding
  mature sunspots. We derive vector magnetic fields of MMFs around
  simple sunspots near the disk center. Most of MMFs with polarity
  opposite to the sunspot have large redshift around the penumbral outer
  boundary. We find that some of them have Doppler velocities of about
  10 km/s and such large Doppler motion is observed only in the Stokes
  V profile. The Stokes Q and U profiles in the same pixel do not have
  any significant Doppler motions. Horizontal magnetic fields of the
  penumbra frequently extend to the moat region and the MMFs having
  horizontal fields with polarity same as the sunspot are formed. The
  MMFs with polarity opposite to the sunspot appear around the outer
  edge of the extending penumbral fields. We also find penumbral spines,
  which have more vertical magnetic fields than the surroundings, branch
  off at their outer edge and MMFs having relatively vertical fields
  with polarity same as the sunspot are detached from the outer edge
  of the branch. The branch of penumbral spine is formed when granular
  cells in the moat region go into the penumbra.

Title: Ubiquitous Horizontal Magnetic Fields in the Quiet Solar
    Photosphere as Revealed by HINODE Meaurements
Authors: Lites, Bruce W.; Socas Navarro, H.; Berger, T.; Frank,
   Z.; Shine, R.; Tarbell, T.; Title, A.; Ichimoto, K.; Katsukawa,
   Y.; Tsuneta, S.; Suematsu, Y.; Kubo, M.; Shimizu, T.; Nagata, S.;
   Hinode Team
Bibcode: 2007AAS...210.6303L
Altcode: 2007BAAS...39..171L
  Measurements with the HINODE Spectro-Polarimeter (SP) of the quiet
  Sun allow characterization of the weak, mixed-polarity magnetic
  flux at the highest angular resolution to date (0.3"), and with good
  polarimetric sensitivity(0.025% relative to the continuum). The image
  stabilization of the HINODE spacecraft allows long integrations with
  degradation of the image quality only by the evolution of the solar
  granulation. From the Stokes V profile measurements we find an average
  solar "Apparent Flux Density" of 14 Mx cm-2, with significant Stokes V
  signals at every position on the disk at all times. However, there are
  patches of meso-granular size (5-15") where the flux is very weak. At
  this high sensitivity, transverse fields produce measurable Stokes
  Q,U linear polarization signals over a majority of the area, with
  apparent transverse flux densities in the internetwork significantly
  larger than the corresponding longitudinal flux densities. When viewed
  at the center of the solar disk, the Stokes V signals (longitudinal
  fields) show a preference for occurrence in the intergranular lanes,
  and the Q,U signals occur preferably over the granule interiors,
  but neither association is exclusive. <P />Hinode is an international
  project supported by JAXA, NASA, PPARC and ESA. We are grateful to the
  Hinode team for all their efforts in the design, build and operation
  of the mission.

Title: Attempt to detect Aflven waves with Solar Optical Telescope
    aboard Hinode
Authors: Tsuneta, Saku; Suematsu, Y.; Ichimoto, K.; Katsukawa, Y.;
   Shimizu, T.; Nagata, S.; Orozco Suárez, D.; Lites, B.; Shine, D.;
   Tarbell, T.; Title, A.
Bibcode: 2007AAS...210.9428T
Altcode: 2007BAAS...39..222T
  Flux tube on the sun may carry linear and torsional Alfven waves
  generated by photospheric motion. Photospheric motion of 2 km/s would
  provide magnetic fluctuation of 40G for 1KG tube and for the Alfven
  speed of 50km/s. This may be close to the detection limit of the Stokes
  Q and U signals for flux tubes located in the sun center. However,
  for flux tubes located near the limb, the fluctuation would be seen in
  the Stokes V signal, and can be detectable. <P />We also may be able
  to confirm the 90 degree phase shift between magnetic fluctuation and
  velocity fluctuation, which is easier to observe for flux tubes near
  the limb. Detection of waves would be important in terms of coronal
  heating and solar wind acceleration. An attempt to detect waves along
  flux tubes will be reported.

Title: Discovery Of Cool Cloud-like Structures In The Corona With
    Hinode Solar Optical Telescope
Authors: Okamoto, Takenori; Tsuneta, S.; Katsukawa, Y.; Ichimoto,
   K.; Suematsu, Y.; Shimizu, T.; Nagata, S.; Shibata, K.; Tarbell, T.;
   Shine, R.; Berger, T.; Lites, B.; Myers, D.
Bibcode: 2007AAS...210.9426O
Altcode: 2007BAAS...39..221O
  A solar observation satellite Hinode (Japanese for sun rise) was
  launched in September 2006.Hinode carried 3 advanced solar telescopes,
  visible light telescope, EUV imaging spectrometer, and X-ray telescope
  to simultaneously observe the photosphere, chromosphere, transition
  region, and corona. In the performance verification phase of the Hinode
  spacecraft with its telescopes, we observed an active region AR10921
  near the west limb of the solar disk on November 9 2006. At this point,
  we planned to observe spicules on the limb with a broadband filter
  dedicated to Ca II H line (3968A). Ca II-H emission line (3968A) comes
  from plasma with temperature of approx. 10(4) K, which is much lower
  than the coronal temperature of 10(6-7) K. In addition to spectacular
  spicules, we find a large cloud-like structure located 10,000-20,000
  km above the limb. The cloud has a very complex fine structure with
  dominant horizontal thread-like structure. Some features are moving
  horizontally and also have clear vertical oscillatory motions. The
  periods and amplitudes of these oscillations are 130-250 seconds and
  200-850 km, respectively. The vertical oscillatory motion sometimes
  has a coherence length as long as 16,000 km. We conclude that from
  various observational features this vertical oscillation is a signature
  of Alfven waves propagating along the horizontal magnetic fields. We
  will discuss their origin and implications.

Title: Discovery Of Small-scale Horizontal Magnetic Structures On
    The Solar Photosphere
Authors: Ishikawa, Ryohko; Tsuneta, S.; Suematsu, Y.; Ichimoto, K.;
   Katsukawa, Y.; Nagata, S.; Ishobe, H.; Tarbell, T.; Lites, B. W.;
   Title, A.
Bibcode: 2007AAS...210.9404I
Altcode: 2007BAAS...39..217I
  We discover two different types of episodes on the appearance
  of horizontal magnetic fields with Solar Optical Telescope aboard
  Hinode. <P />The first episode is an emergence of strong thin horizontal
  magnetic fields associated with separating vertical components on
  both ends. Its size is about two granules. We also detect strong area
  asymmetry of the environment Stokes Vprofile for the bout 8 minutes
  before the first emergence of the horizontal component. One of the
  footpoints has very strong downflows (several km/s), while the region
  with strong linear polarization signal has small blue shift, indicating
  an upward-moving horizontal flux. <P />The second episode appears to be
  more ubiquitous. Linear polarization signals appear inside granules (not
  in inter-granules). Their size is smaller than granules, and lifetime
  is longer than several minutes. We will summarize the nature of the
  two types of the horizontal magnetic fluxes, and discuss their origin.

Title: Optical Performance of the Solar Optical Telescope aboard
    HINODE
Authors: Suematsu, Yoshinori; Ichimoto, K.; Katsukawa, Y.; Otsubo,
   M.; Tsuneta, S.; Nakagiri, M.; Noguchi, M.; Tamura, T.; Kato, Y.;
   Hara, H.; Miyashita, M.; Shimizu, T.; Kubo, M.; Sakamoto, Y.
Bibcode: 2007AAS...210.9402S
Altcode: 2007BAAS...39Q.217S
  The Solar Optical Telescope (SOT) carried by HINODE was designed
  to perform a high-precision polarimetric observation of the Sun
  in visible light spectra with a spatial resolution of 0.2 - 0.3
  arcseconds. The SOT is a sophistcated instrument and consists of two
  separate optical parts; the Optical Telescope Assembly (OTA) which is
  50 cm aperture Gregorian telescope feeding the light into following
  observing instruments which is called the focal plane package (FPP)
  made of two filtergraphs and a spectro-polarimeter. The performance
  of the OTA is important because a spatial resolution and its temporal
  stability is mainly determined by this component. To keep the OTA in
  moderate temperature and optical thermal deformation small, it equipped
  newly designed components such as a heat dump and a secondary field stop
  aluminum mirror with high reflectivity silver coating and a temperature
  low-sensitive apochromatic collimataing lens unit with a UV/IR cut
  coating on the first surface. In addition, the SOT has an active image
  stabilization system consisting of correlation tracker, tip-tilt mirror
  and its controller against satellite pointing jitter. It was confirmed
  that this system freezes residual motion to the 0.01 arcsecond level
  on orbit. The image of sub-arcsecond G-band (430.5 nm) bright points
  clearly indicates that the SOT achieves the diffraction-limit on orbit;
  this is also confirmed using a phase diversity method. In this paper,
  we describe details of the design and on-orbit performance of the OTA.

Title: Magnetic Landscape Of Solar Polar Region With Solar Optical
    Telescope Aboard Hinode
Authors: Tsuneta, Saku; Suematsu, Y.; Ichimoto, K.; Shimizu, T.;
   Katsukawa, Y.; Nagata, S.; Orozco Suárez, D.; Lites, B.; Shine, D.;
   Tarbell, T.; Title, A.
Bibcode: 2007AAS...210.9405T
Altcode: 2007BAAS...39..218T
  Solar polar region is the final destination for remnant magnetic
  fields due to meridional flow and granular diffusion, and is very
  important for the global solar dynamo. Hinode satellite carried out
  high-resolution spectro-polarimetric observations for the Northern
  pole on 2006 November 22 as a part of its performance verification
  program. We find ubiquitous isolated (positive and negative) patches
  in the Stokes V map (i.e. fields horizontal to local surface) all over
  the Arctic circle. The Q (vertical to local surface) map indicates
  scattered vertical flux tubes, which have bipolar feature in the U and
  V maps. This suggests canopy-like structure of the strong isolated flux
  tubes. This will be compared with equatorial landscape with similar
  distance from the sun center. Strong flux tube and weaker ubiquitous
  horizontal fields as represented by Stokes V would have implication
  to the current understanding of the global and local dynamo.

Title: Evidence Of An Association Between The Presence Of Penumbrae
    And Strong Radial Outflows In Sunspots
Authors: Santiago, Vargas Domínguez; Bonet, J. A.; Martinez Pillet,
   V.; Katsukawa, Y.
Bibcode: 2007ESASP.641E..87S
Altcode:
  Time series of high-resolution images of the complex ac-tive region NOAA
  10786 are studied. The observations were performed in G-band (430.5 nm)
  and in the nearby continuum (463.3 nm), on July 9, 2005 at the Swedish
  1-meter Solar Telecope (SST) in La Palma. Granular proper motions in the
  surroundings of the sunspots have been quantified. A large-scale radial
  outflow in the velocity range 0.3 - 1 km s-1 has been measured around
  the sunspots by using local correlation tracking techniques. However,
  this outflow is not found in those regions around the sunspots with
  no penumbral structure. This result evidences an association between
  penumbrae and the existence of strong horizontal outflows (the moat)
  in sunspots.

Title: Magnetic Field Diagnostic Capability of Solar-B/SOT:
    Filtergraph Instrument
Authors: Ichimoto, K.; Suematsu, Y.; Shimizu, T.; Katsukawa, Y.;
   Tsuneta, S.; Tarbell, T. D.; Shine, R. A.; Hoffmann, C. M.; Title,
   A. M.; Lites, B. W.; Elmore, D. F.; Streander, K. V.
Bibcode: 2006ASPC..358..189I
Altcode:
  The Narrowband Filter Instrument (NFI) of the Solar Optical Telescope
  onboard Solar-B provides 2D magnetograms/Dopplergrams with a tunable
  Lyot filter (width ∼ 0.1 Å) in 6 selected wavelength bands, and
  spatial sampling of 0.08 arcsec/px. The Zeeman-effect sensitivity of
  NFI and the detection limits of weak magnetic fields are evaluated for
  2 photospheric and 3 chromospheric lines. Magnetic-field retrievability
  from the NFI observables is studied using synthetic Stokes profiles
  of Fe I 5250 Å. We find that, with optimized wavelength sampling at 4
  positions, the inferred magnetic field is sufficiently accurate under
  the hypothesis of constant magnetic field and velocity along the LOS.

Title: Evidence of an association between the presence of penumbrae
    and strong radial outflows in sunspots
Authors: Vargas Domínguez, S.; Bonet, J. A.; Martinez Pillet, V.;
   Katsukawa, Y.
Bibcode: 2006astro.ph.11500V
Altcode:
  Time series of high-resolution images of the complex active region NOAA
  10786 are studied. The observations were performed in G-band (430.5 nm)
  and in the nearby continuum (463.3 nm), on July 9, 2005 at the Swedish
  1-meter Solar Telecope (SST) in La Palma. Granular proper motions in the
  surroundings of the sunspots have been quantified. A large-scale radial
  outflow in the velocity range 0.3 - 1 km s^[-1] has been measured around
  the sunspots by using local correlation tracking techniques. However,
  this outflow is not found in those regions around the sunspots with
  no penumbral structure. This result evidences an association between
  penumbrae and the existence of strong horizontal outflows (the moat)
  in sunspots.

Title: Hard X-Ray Spectral Observation of a High-Temperature
    Thermal Flare
Authors: Kobayashi, Ken; Tsuneta, Saku; Tamura, Tomonori; Kumagai,
   Kazuyoshi; Katsukawa, Yukio; Kubo, Masahito; Sakamoto, Yasushi;
   Kohara, Naoki; Yamagami, Takamasa; Saito, Yoshitaka
Bibcode: 2006ApJ...648.1239K
Altcode:
  We report on the analysis of a thermal flare observed by a newly
  developed balloon-borne hard X-ray spectrometer. This instrument uses
  CdTe detectors and can observe the 20-120 keV hard X-ray range, with
  3.0 keV energy resolution at 60 keV. During the 2002 May 24 flight,
  it successfully observed a class M1.1 flare. This flare observation
  shows no detectable flux above 35 keV, and its spectrum is consistent
  with a superhot thermal source with the temperature varying from 44
  to 20 MK. Partial observation of the flare by the RHESSI satellite is
  consistent with this result. The Nobeyama Radio Polarimeters (NORP)
  observation of this flare shows no detectable polarization. The NORP
  light curves show impulsive features at 3.75 GHz that can be explained
  as thermal gyrosynchrotron emission, and this flux is consistent with
  observed X-ray spectra if a magnetic field of 275 G is assumed. Slower
  varying features seen in the NORP data are consistent with the
  lower temperature (``hot'') thermal source of 10-15 MK seen in soft
  X-rays. We conclude that this flare shows no observable signature of
  nonthermal electrons, and all observed features are consistent with
  a purely thermal event. This serves as a strong indication that a
  nonthermal electron beam is not always the dominant energy source of
  plasma heating in solar flares.

Title: Dynamical Properties of Photospheric Flux Tubes at the
    Footpoints of Hot and Cool Coronal Loops
Authors: Nagata, Shin'ichi; Bellot Rubio, Luis R.; Katsukawa, Yukio
Bibcode: 2006ApJ...638..539N
Altcode:
  The dynamical properties of photospheric flux tubes at the footpoints
  of hot (T&gt;2 MK) and cool (T=1-2 MK) coronal loops in active region
  plages are investigated by analyzing the Stokes V profile parameters of
  Fe I λ6302. We show that the footpoints of both hot and cool loops are
  located at the periphery of small magnetic concentrations, such as pores
  and azimuth centers, having a field strength of 1-1.8 kG and a spatial
  size of 2"-5". The footpoints of cool loops seem to be associated with
  more densely packed and higher field strength pores and azimuth centers
  than those of hot loops. Enhanced Stokes V asymmetries, redshifted
  zero-crossing velocities, and small magnetic filling factors are found
  at the footpoints of both types of loops, as compared with outside
  the footpoints. However, the largest asymmetries and more redshifted
  zero-crossing velocities are observed at the footpoints of hot loops,
  where the filling factor is smaller than at the footpoints of cool
  loops. The differences between the profiles emerging from the footpoints
  of hot and cool coronal loops suggest that heating of the coronal loops
  could be related to the dynamical properties of photospheric flux tubes.

Title: Probing coronal heating with variability of solar X-ray
    emission
Authors: Vekstein, G.; Jain, R.; Katsukawa, Y.; Tsuneta, S.
Bibcode: 2006cosp...36...65V
Altcode: 2006cosp.meet...65V
  If the mechanism responsible for creating hot solar corona is a
  magnetic one the resulting coronal heating events are likely to be
  highly fragmented in space and in time This makes the nanoflare
  heating scenario where both these features are at the heart of
  the concept a strong candidate The major problem is to find out
  how to test this theory while individual nanoflares remain beyond
  observational recognition Here we discuss a possibility of probing
  nanoflares with variability of the coronal X-ray emission We present
  results of the numerical simulation of X-ray coronal loops that mimics
  a sporadic nature of the nanoflare heating The aim is to investigate
  how an imposed power-law energy spectrum of heating events nanoflares
  translates into fluctuations in the intensity of the X-ray emission
  which can be detected observationally as X-ray and EUV brightenings
  These theoretical predictions are compared with a recently reported
  analysis of observed fluctuations of the solar X-ray emission and
  we discuss their implications on the deduced energy and spectrum of
  nanoflares A future study envisaged with the upcoming Solar-B mission
  is also discussed

Title: Magnetic Properties at Footpoints of Hot and Cool Loops
Authors: Katsukawa, Yukio; Tsuneta, Saku
Bibcode: 2005ApJ...621..498K
Altcode:
  Observations of the solar corona with Yohkoh, the Solar and Heliospheric
  Observatory, and the Transition Region and Coronal Explorer (TRACE)
  have revealed that individual coronal loops of active regions have their
  own temperatures from 1 to 5 MK. The hot (2-5 MK) Soft X-Ray Telescope
  (SXT) loops appear to require more heating energy than the cool (1-2 MK)
  EUV loops. We investigate the photospheric magnetic signature for the
  hot and cool loops with the Advanced Stokes Polarimeter. In contrast to
  the cool loops, the hot loops observed with the SXT are usually diffuse,
  resulting in ambiguous identification of their footpoint locations. We
  use TRACE ``moss'' structure, which we confirm is low-lying EUV emission
  at the footpoints of the hot loops. Footpoints of both loops have
  magnetic fields whose strength is 1.2-1.3 kG, and the orientation is
  almost vertical to the surface. A significant difference is discovered
  in the magnetic filling factor, which is defined by the fraction of
  a pixel filled with a magnetized atmosphere. The footpoints of the
  hot loops have a lower filling factor than the footpoints of the cool
  loops. We suggest that braiding of coronal magnetic fields is more
  efficient at the footpoints of the hot loops than at the footpoints
  of the cool loops as a result of the combination of the lower filling
  factor and higher horizontal velocity.

Title: Completion of Solar-B/Optical Telescope flight model
Authors: Suematsu, Yoshinori; Ichimoto, Kiyosi; Shimizu, Toshifumi;
   Otsubo, Masashi; Nakagiri, Masao; Noguchi, Motokazu; Tamura, Tomonori;
   Katsukawa, Yukio; Kato, Yoshihiro; Hara, Hirohisa; Miyashita, Masakuni;
   Tsuneta, Saku; Kubo, Masahito; Sakamoto, Yasushi
Bibcode: 2005ARAOJ...7...52S
Altcode:
  No abstract at ADS

Title: Observation of solar flare hard X-ray spectra using CdTe
    detectors
Authors: Kobayashi, Ken; Tsuneta, Saku; Tamura, Tomonori; Kumagai,
   Kazuyoshi; Katsukawa, Yukio; Kubo, Masahito; Sakamoto, Yasushi;
   Kohara, Naoki; Yamagami, Takamasa; Saito, Yoshitaka; Mori, Kunishiro;
   Kato, Genzo
Bibcode: 2005naoj.book...33K
Altcode:
  No abstract at ADS

Title: Solar-B/Optical Telescope flight model is coming up
Authors: Suematsu, Yoshinori; Ichimoto, Kiyoshi; Shimizu, Toshifumi;
   Otsubo, Masashi; Nakagiri, Masao; Noguchi, Motokazu; Tamura, Tomonori;
   Kato, Yoshihiro; Hara, Hirohisa; Miyashita, Masakuni; Tsuneta, Saku;
   Katsukawa, Yukio; Kubo, Masahito; Sakamoto, Yasushi
Bibcode: 2005naoj.book....4S
Altcode:
  No abstract at ADS

Title: Magnetic properties at the footpoints of hot and cool loops
Authors: Katsukawa, Yukio; Tsuneta, Saku
Bibcode: 2005naoj.book...27K
Altcode:
  No abstract at ADS

Title: The first build-up of the Solar-B flight models
Authors: Hara, Hirohisa; Ichimoto, Kiyoshi; Otsubo, Masashi; Katsukawa,
   Yukio; Kato, Yoshihiro; Kano, Ryohei; Kumagai, Kazuyoshi; Shibasaki,
   Kiyoto; Shimizu, Toshifumi; Shimojo, Masumi; Suematsu, Yoshinori;
   Tamura, Tomonori; Tsuneta, Saku; Noguchi, Motokazu; Nakagiri, Masao;
   Miyashita, Masakuni; Watanabe, Tesuya; Kosuchi, Takeo; Sakao, Taro;
   Matsuzaki, Keiichi; Kitakoshi, Yasunori; Kubo, Masahito; Sakamoto,
   Yasushi
Bibcode: 2005ARAOJ...7...46H
Altcode:
  No abstract at ADS

Title: Hard X-Ray Spectral Observation of a High-Temperature
    Thermal Flare
Authors: Kobayashi, K.; Katsukawa, Y.; Kubo, M.; Sakamoto, Y.; Kohara,
   N.; Tsuneta, S.; Tamura, T.; Kumagai, K.; Yamagami, T.; Saito, Y.
Bibcode: 2004ASPC..325..353K
Altcode:
  No abstract at ADS

Title: Multi-Temperature Corona and the Photospheric Magnetic Fields
Authors: Katsukawa, Y.; Tsuneta, S.
Bibcode: 2004ASPC..325..281K
Altcode:
  No abstract at ADS

Title: Coronal Heating with Sweet-Parker Picoflares
Authors: Tsuneta, S.; Katsukawa, Y.
Bibcode: 2004ASPC..325..289T
Altcode:
  Katsukawa &amp; Tsuneta (2001) found an excess fluctuation in soft
  X-rays coming from active regions, and proposed that the fluctuation
  was attributed to ubiquitous tiny bursts. They estimated the energy
  range of individual bursts to be 10<SUP>20</SUP>--10<SUP>22</SUP>
  erg. There appears to be a big desert, the void in which no burst
  occurs for 3--6 orders of magnitudes in energy from the pico-flare
  range to the observed micro-flare range, indicating that a separate
  physical mechanism is responsible for the picoflares. We propose that
  the picoflares are due to Sweet-Parker reconnection, which is presumably
  easier to occur than the Petschek reconnection responsible for larger
  flares. We point out the critical importance of the simultaneous
  observations with SolarB X-ray/EUV and visible-light telescopes.

Title: Nanoflares and Coronal X-Ray Variability
Authors: Jain, R.; Katsukawa, Y.; Tsuneta, S.; Vekstein, G.
Bibcode: 2004ASPC..325..271J
Altcode:
  A possibility of probing nanoflares with variability in the coronal
  X-ray emission is discussed. We present results of numerical simulation
  of X-ray coronal loops by using a Monte Carlo code, which mimics a
  sporadic nature of the nanoflare heating. The aim is to investigate how
  the imposed power-law energy spectrum of heating events (nanoflares)
  translates into fluctuations in the intensity of the X-ray emission,
  which can be detected observationally as X-ray and EUV brightenings. It
  was found that probability distribution of these fluctuations is
  very sensitive to the power-law index α of the energy spectrum of
  nanoflares. If α &gt; 3, intensity fluctuations have a noise-like
  nature with a Gaussian distribution originating from interference of
  many small nanoflares. For spectral indices 2 &lt; α ≤ 3, histograms
  of the intensity deviation from the mean value show positive skewness
  indicating significant role of bigger events. Comparison of these
  results with the analysis of small fluctuations of coronal X-ray
  intensity observed with Yohkoh SXT telescope yields an estimate of
  10<SUP>23</SUP> erg for the energy of nanoflares in the active region.

Title: The Solar Optical Telescope onboard the Solar-B
Authors: Ichimoto, Kiyoshi; Tsuneta, Saku; Suematsu, Yoshinori;
   Shimizu, Toshifumi; Otsubo, Masashi; Kato, Yoshihiro; Noguchi,
   Motokazu; Nakagiri, Masao; Tamura, Tomonori; Katsukawa, Yukio; Kubo,
   Masahito; Sakamoto, Yasushi; Hara, Hirohisa; Minesugi, Kenji; Ohnishi,
   Akira; Saito, Hideo; Kawaguchi, Noboru; Matsushita, Tadashi; Nakaoji,
   Toshitaka; Nagae, Kazuhiro; Sakamoto, Joji; Hasuyama, Yoshihiro;
   Mikami, Izumi; Miyawaki, Keizo; Sakurai, Yasushi; Kaido, Nobuaki;
   Horiuchi, Toshihida; Shimada, Sadanori; Inoue, Toshio; Mitsutake,
   Masaaki; Yoshida, Norimasa; Takahara, Osamu; Takeyama, Norihide;
   Suzuki, Masaharu; Abe, Shunichi
Bibcode: 2004SPIE.5487.1142I
Altcode:
  The solar optical telescope onboard the Solar-B is aimed to perform a
  high precision polarization measurements of the solar spectral lines
  in visible wavelengths to obtain, for the first time, continuous
  sets of high spatial resolution (~0.2arcsec) and high accuracy
  vector-magnetic-field map of the sun for studying the mechanisms
  driving the fascinating activity phenomena occurring in the solar
  atmosphere. The optical telescope assembly (OTA) is a diffraction
  limited, aplanatic Gregorian telescope with an aperture of Φ500mm. With
  a collimating lens unit and an active folding mirror, the OTA provides
  a pointing-stabilized parallel beam to the focal plane package (FPP)
  with a field of view of about 360x200arcsec. In this paper we identify
  the key technical issues of OTA for achieving the mission goal and
  describe the basic concepts in its optical, mechanical and thermal
  designs. The strategy to verify the in-orbit performance of the
  telescope is also discussed.

Title: Heating of the solar corona and fine magnetic structure in
    the photosphere
Authors: Katsukawa, Yukio
Bibcode: 2004AstHe..97..571K
Altcode: 2004AstHe..97..571N
  It is important to investigate magnetic connection between the
  photosphere and the corona for understanding the heating mechanism
  of the solar corona. We investigate what magnetic signature in
  the photosphere is responsible for the difference in the coronal
  temperature, and find that number density of fine magnetic elements
  (magnetic filling factor) is significantly correlated with the heating
  rate of the corona. This result suggests that motion of the magnetic
  elements in the photosphere plays an important role in the heating of
  the corona. The Solar-B satellite, which will be launched in 2006,
  will provide an opportunity to perform direct investigation of the
  correlation between the photospheric motion of fine magnetic elements
  and the coronal heating.

Title: Observation of solar flare hard X-ray spectra using CdTe
    detectors
Authors: Kobayashi, K.; Tsuneta, S.; Tamura, T.; Kumagai, K.;
   Katsukawa, Y.; Kubo, M.; Sakamoto, Y.; Kohara, N.; Yamagami, T.;
   Saito, Y.; Mori, K.
Bibcode: 2004AdSpR..33.1786K
Altcode:
  We present the design and initial flight results of a balloon-borne
  hard X-ray spectrometer for observing solar flares. The instrument
  is designed for quantitative observation of nonthermal and thermal
  components of solar flare hard X-ray emission, and has an energy range
  of 15-120 keV and an energy resolution of 3 keV. The instrument is
  a small (gondola weight 70 kg) system equipped with sixteen 10 ×
  10 × 0.5 mm CdTe detectors, and designed for a 1-day flight at 41
  km altitude. Detector temperature of -15 °C was achieved through
  radiative cooling alone. Pre-flight tests confirmed that all detectors
  exceeded the target 3 keV resolution. No flares were observed during
  the 2001 flight, but the second flight on May 24, 2002 succeeded
  in observing a class M1.1 flare. Preliminary analysis indicates the
  observed spectrum is consistent with a purely thermal plasma at an
  unusually high temperature of 47 mK.

Title: Observation of solar flare hard X-ray spectra using CdTe
    detectors
Authors: Kobayashi, Ken; Tsuneta, Saku; Tamura, Tomonori; Kumagai,
   Kazuyoshi; Katsukawa, Yukio; Kubo, Masahito; Sakamoto, Yasushi;
   Kohara, Naoki; Yamagami, Takamasa; Saito, Yoshitaka; Mori, Kunishiro;
   Kato, Genzo
Bibcode: 2004naoj.book...38K
Altcode:
  No abstract at ADS

Title: What determines the coronal heating rate in the photosphere?
Authors: Katsukawa, Y.; Tsuneta, S.
Bibcode: 2004cosp...35.2233K
Altcode: 2004cosp.meet.2233K
  Observations of the solar corona with Yohkoh/SXT, SOHO/EIT and TRACE
  have revealed that individual loops of active region corona have their
  own temperatures from 1 MK to 5 MK. The most significant difference
  between hot (2 - 5 MK) SXT loops and cool (1 - 2 MK) EUV ones is that
  heat input to maintain the hot loops is about one order of magnitude
  larger than that for the cool loops. We investigate the photospheric
  magnetic signature for the hot and cool loops with the Advanced Stokes
  Polarimeter (ASP) to clarify what makes such a large difference in the
  heat input. Footpoints of both loops have magnetic fields whose strength
  is 1.2 - 1.3 kG and the orientation is almost vertical to the surface. A
  significant difference is discovered in the magnetic filling factor,
  which is defined by the fraction of a pixel filled with a magnetized
  atmosphere. The footpoints of the hot loops have significantly lower
  filling factor than the footpoints of the cool loops. If we interpret
  the lower filing factor as multiple granular magnetic elements in
  an ASP pixel, those elemental magnetic footpoints combined with
  photospheric motion would provide enhanced coronal heating, leading
  to the hot loops. Solar-B and STEREO will provide an opportunity to
  perform direct investigation of the correlation between the photospheric
  motion of magnetic elements and the coronal temperature.

Title: Thermo-optical testing of the solar optical telescope of
    the Solar-B
Authors: Ichimoto, Kiyoshi; Nakagiri, Masao; Suematsu, Yoshinori;
   Tamura, Tomonori; Tsuneta, Saku; Noguchi, Motokazu; Kato, Yoshihiro;
   Otsubo, Seiji; Katsukawa, Yukio; Kubo, Masahito
Bibcode: 2004naoj.book....6I
Altcode:
  No abstract at ADS

Title: Spatial and Temporal Extent of Solar Nanoflares and Their
    Energy Range
Authors: Katsukawa, Yukio
Bibcode: 2003PASJ...55.1025K
Altcode:
  Coronal X-ray emission observed with the Yohkoh Soft X-ray Telescope
  (SXT) fluctuates with an amplitude larger than the Poisson photon
  noise, as shown in our previous paper (Katsukawa, Tsuneta 2001, ApJ,
  557, 343). This fluctuation is attributed to small energy events
  (``nanoflares'') that cannot be identified as individual bursts. We
  present here a detailed analysis of the fluctuation, particularly
  concerning the spatial and temporal extents of the fluctuating
  sources. A macro-pixel analysis of the intensity fluctuation reveals
  that the spatial extent of the fluctuation is a few pixels of
  SXT. The scale size may be due to the point-spread function of SXT,
  and/or indicates the intrinsic size of the fluctuating source. An
  auto-correlation analysis gives a loose upper limit of the time scale,
  1 minute. Taking into account the spatial and temporal scales, the
  energy of nanoflares estimated in the previous paper is updated to be
  10<SUP>22</SUP> to 10<SUP>22</SUP> erg.

Title: Development and flight performance of the sun sensor for
    balloon observation
Authors: Tamura, Tomonori; Kobayashi, Ken; Tsuneta, Saku; Kubo,
   Masahito; Katsukawa, Yukio
Bibcode: 2003RNAOJ...6..117T
Altcode:
  We developed a sun-sensor for the balloon mission to observe solar
  flare hard X-ray spectra using CdTe detectors. The sensor utilizes a
  position-sensitive detector (PSD) with a pinhole, and has 60 degrees ×
  60 degrees field-of-view with a 1 degree resolution. The sun-sensor
  operated nominally during the two flights. We report the design,
  ground calibration, and flight performance.

Title: Balloon-borne hard x-ray spectrometer for flare observations
Authors: Kobayashi, Ken; Tsuneta, Saku; Tamura, Tomonori; Kumagai,
   Kazuyoshi; Katsukawa, Yukio; Kubo, Masahito; Yamagami, Takamasa;
   Saito, Yoshitaka
Bibcode: 2003SPIE.4851.1009K
Altcode:
  We present the design and initial flight results of a balloon-borne
  hard X-ray detector system for observing high-resolution spectra of
  solar flares. The instrument is designed to achieve a 3 keV energy
  resolution over the energy range of 15-120 keV. The instrument uses
  sixteen 10×10×0.5mm cadmium telluride (CdTe) detectors with indium
  electrodes that act as Schottky barriers. Pre-flight tests confirmed
  that all detectors exceeded the target 3 keV resolution. The detector
  system is designed to optimize radiative cooling in order to achieve
  the operating temperature of 0°C without refrigeration mechanisms. The
  first flight took place on August 29, 2001 and while no major flares
  were observed, the instrument operation was verified and a detector
  temperature of -13° C was achieved. The second flight took place on
  May 24, 1974 and during the 8 hours of level flight at an altitude of
  41km, we succeeded in observing a class M1.1 solar flare.

Title: Development of the Solar-B spacecraft
Authors: Tsuneta, Saku; Ichimoto, Kiyoshi; Suematsu, Yoshinori;
   Shimizu, Toshifumi; Hara, Hirohisa; Kano, Ryohei; Nagata, Shin'ichi;
   Tamura, Tomonori; Nakagiri, Masao; Noguchi, Motokazu; Kato, Yoshihiro;
   Watanabe, Tetsuya; Hanaoka, Yoichiro; Sawa, Masaki; Otsubo, Masashi;
   Kosugi, Takeo; Yamada, Takahiro; Sakao, Taro; Matsuzaki, Keiichi;
   Minesugi, Kenji; Onishi, Akira; Katsukawa, Yukio; Kobayashi, Ken;
   Kubo, Masahito
Bibcode: 2003naoj.book....3T
Altcode:
  No abstract at ADS

Title: Development of Solar-B solar optical telescope
Authors: Suematsu, Yoshinori; Ichimoto, Kiyoshi; Shimizu, Toshifumi;
   Nagata, Shin'ichi; Tamura, Tomonori; Tsuneta, Saku; Noguchi, Motokazu;
   Kato, Yoshihiro; Nakagiri, Masao; Otsubo, Masashi; Hanaoka, Yoichiro;
   Katsukawa, Yukio; Kobayashi, Ken; Kubo, Masahito
Bibcode: 2003naoj.book....5S
Altcode:
  No abstract at ADS

Title: Small fluctuation of coronal X-ray intensity: possibility of
    nanoflare heating
Authors: Katsukawa, Yukio; Tsuneta, Saku
Bibcode: 2003naoj.book...41K
Altcode:
  No abstract at ADS

Title: Balloon-Borne Hard X-ray Spectrometer for Flare Observations
Authors: Kobayashi, K.; Tsuneta, S.; Tamura, T.; Kumagai, K.;
   Katsukawa, Y.; Kubo, S.; Yamagami, T.; Saitoh, Y.
Bibcode: 2002mwoc.conf..429K
Altcode:
  We present an overview of a balloon-borne hard X-ray detector system
  designed for high spectral resolution observation of solar flares. The
  goal is to achieve a 3-keV energy resolution over an energy range of
  15--100 keV, to observe both non-thermal and thermal components of the
  solar flare hard X-ray emission. We achieve this by using an array of
  16 CdTe detectors, each with a 10 times 10 times 0.5 mm size. These
  detectors use an Indium electrode on one side which act as a Shottky
  barrier, reducing leak current and improving energy resolution compared
  to conventional CdTe detectors. The detectors are passively shielded by
  2 mm of lead. The detectors are installed in a pressurized enclosure to
  prevent coronal discharge. In order to maximize passive cooling, thermal
  shields are installed around the detector housing to block sunlight and
  infrared emission from the ground. Thermal math models indicate that
  the detectors will be cooled to below 0<SUP>circ</SUP>C. The signal
  from the 16 detectors are processed by independent preamplifiers and
  amplifiers, and a custom-designed 16 channel multichannel analyzer
  acquires the signal and constructs 16 independent spectra. These are
  read every 0.56 seconds and transmitted by telemetry. A 0.14 second
  resolution counter is used to correct for dead time. The instrument
  is currently undergoing testing and calibration, and first flight is
  scheduled for September 2001 from an ISAS (Institute of Space and
  Astronautical Science) facility in Sanriku, Japan. The flight will
  last one day at an altitude of 42 km.

Title: Small Fluctuations of Coronal X-ray Intensity: A Signature
    of Nanoflares
Authors: Katsukawa, Y.; Tsuneta, A.
Bibcode: 2002mwoc.conf...61K
Altcode:
  If small energy events (nanoflares) contribute to the heating of the
  solar corona, they may be too small to be recognized as independent
  events. We analyze fluctuation of X-ray intensity observed with Soft
  X-Ray Telescope (SXT) aboard Yohkoh satellite to detect the tiny events
  which may occur in the solar corona. When we create a simple histogram
  of the X-Ray intensity fluctuation around mean intensity, we find that
  the histogram consists of a central Gaussian component and a wing
  component. The Gaussian component corresponds to random fluctuation
  around the mean X-ray intensity. The width of this component becomes
  broader with increasing intensity, and is larger than the width of
  the predicted photon noise distribution. We suggest that nanoflares
  produce the observed fluctuation of the X-ray intensity. We derive
  the analytical expression for the intensity fluctuation to estimate
  the individual energy of nanoflares from the observed intensity
  fluctuation. The intensity fluctuation can be related with the mean
  X-ray intensity, the energy of nanoflares, and the time scale of
  individual nanoflares. By comparing the observed fluctuation with the
  analytical expression, we are able to estimate the individual energy
  of nanoflares. The estimated energy ranges from 10<SUP>20</SUP> to
  10<SUP>23</SUP> ergs. The observed fluctuation corresponds to an energy
  much smaller than previously predicted energy. It is estimated that if
  the energy of nanoflares is 10<SUP>21</SUP> ergs, then these nanoflares
  must occur at a rate of 10<SUP>5</SUP> s<SUP>-1</SUP> in a single active
  region (sim 10<SUP>20</SUP> cm<SUP>2</SUP>) to supply the required
  energy (~ 5 times 10<SUP>7</SUP> ergs cm<SUP>-2</SUP>s<SUP>-1</SUP>)
  to maintain the solar corona.

Title: Observation of solar flare hard x-ray spectra using CdTe
    detectors
Authors: Kobayashi, K.; Tsuneta, S.; Tamura, T.; Kumagai, K.;
   Katsukawa, Y.; Kubo, M.; Sakamoto, Y.; Yamagami, T.; Saito, Y.;
   Mori, K.
Bibcode: 2002cosp...34E1971K
Altcode: 2002cosp.meetE1971K
  We present the design and flight results of a balloon-borne hard
  X-ray detector system for observing high-resolution spectra of solar
  flares. The instrument is designed to achieve a 3 keV energy resolution
  over the energy range of 15-120 keV. The instrument uses sixteen 10 ×
  10 × 0.5 mm cadmium telluride (CdTe) detectors with indium electrodes
  that act as Schottky barriers to minimize leak current and allow a high
  bias voltage. Pre-flight tests confirmed that all detectors exceeded
  the target 3 keV resolution. The pressurized detector vessel uses
  a low-density (0.1 g/cm^2) CFRP/Rohacell window. The detectors are
  passively shielded by 2 mm of lead, and field of view is constrained
  with a graded-Z collimator. The vertical angle of the detectors are
  fixed at 45 degrees, and the azimuth angle of the entire gondola
  is controlled using a signal from a sun position sensor. Specially
  developed electronics accumulate a 128 channel spectrum for each
  detector, which is read through telemetry every 0.54 seconds. These
  detectors need to be cooled down to 0 degrees C for optimal performance;
  due to weight constraints this was achieved purely by radiative cooling,
  using the detector enclosure surface as a radiator and by placing
  shields that minimize radiative heat input from the sun and earth while
  maximizing heat loss to the sky. The first flight of the instrument
  took place on August 29, 2001 and while no major flares were observed,
  we succeeded in detecting a small brightening (microflare). Detector
  temperature of -13 degrees C was achieved, and all systems performed
  as expected. The instrument was recovered successfully after the flight
  and a second flight is planned for May 2002.

Title: Small Fluctuation of Coronal X-Ray Intensity and a Signature
    of Nanoflares
Authors: Katsukawa, Yukio; Tsuneta, Saku
Bibcode: 2001ApJ...557..343K
Altcode:
  If small energy events (nanoflares) contribute to the heating of the
  solar corona, they may be too small to be recognized as independent
  events. We create a simple histogram of the X-ray intensity fluctuation
  around the mean intensity and find that the histogram consists of a
  central Gaussian component and a wing component. The Gaussian component
  corresponds to random fluctuation around the mean intensity. The width
  of this component becomes broader with increasing intensity and is
  larger than the predicted photon noise distribution. We suggest that
  nanoflares produce the observed fluctuation of the X-ray intensity. The
  energy of nanoflares is estimated to be less than 10<SUP>22</SUP> ergs
  to explain the observed fluctuation for active regions. It is estimated
  that if the energy of nanoflares is 10<SUP>20</SUP> ergs, then these
  nanoflares must occur at a rate of 10<SUP>6</SUP> s<SUP>-1</SUP> in a
  single active region (~10<SUP>20</SUP> cm<SUP>2</SUP>) to supply the
  required energy (~5×10<SUP>7</SUP> ergs cm<SUP>-2</SUP> s<SUP>-1</SUP>)
  to maintain the corona.

Title: Scaling Laws for a Nanoflare-Heated Solar Corona
Authors: Vekstein, G.; Katsukawa, Y.
Bibcode: 2000ApJ...541.1096V
Altcode:
  The concept that the solar corona is heated by numerous small flarelike
  events dubbed ``nanoflares'' is considered. The hot corona is viewed as
  an ensemble of high-temperature elemental magnetic filaments created
  within the coronal magnetic field by randomly distributed impulsive
  heating events. It is shown that such an approach allows us to predict
  various signatures of X-ray coronal loops without specifying the
  details of the heating process. In particular, the dependence of the
  temperature, filling factor, and emission measure on the length of
  the loop and strength of the coronal magnetic field is derived. The
  obtained scaling laws fit reasonably with observational data.

