Author name code: firstova
ADS astronomy entries on 2022-09-14
author:"Firstova, N. M." 
------------------------------------------------------------------------  

Title: Structure and physical conditions in the Hα loops of an M7.7
    solar flare
Authors: Firstova, N. M.; Polyakov, V. I.
Bibcode: 2017AstL...43..768F
Altcode:
  No abstract at ADS

Title: Connection between the appearance of γ-ray sources and H α
    line impact linear polarization in the July 23, 2002 flare
Authors: Firstova, N. M.
Bibcode: 2015AstL...41..593F
Altcode:
  During our spectropolarimetric observations of the 2B/4.8X flare
  on July 23, 2002, with the Large Solar Vacuum Telescope (LSVT),
  we detected impact linear polarization in the southern ribbon. The
  maximum polarization exceeded 10%. On the whole, the polarization
  was observed only for ~6 min out of almost 2 h of observations of
  this flare. At this time, the H α line profiles had a deep central
  self-reversal. We have compared the LSVT observations with the Reuven
  Ramaty High Energy Solar Spectroscopic Imager (RHESSI) data, where
  the locations of γ-ray emission were obtained for the first time. A
  careful comparison has revealed that the effects in the H α line were
  observed in a region &lt;10″ located between two X-ray sources in
  the southern ribbon. According to the RHESSI data, a γ-ray source
  attributable to a beam of high-energy (~1 MeV) electrons was observed
  at the same place. The events in the corona and the upper chromosphere
  also coincide in time with the observed effects in the H α line. The
  two X-ray sources are assumed to represent a common footpoint of
  the southern foot of the loop bifurcated due to the precipitation of
  high-energy electrons. It is suggested that the penetration of these
  electrons into the dense layers of the chromosphere could lead to
  impact polarization and a decrease of the H α line intensity in the
  southern ribbon of the flare, in contrast to the northern ribbon where
  a typical hard X-ray source with an energy ~20-120 keV was observed;
  there were no self-reversal at the H α line center and polarization.

Title: Observation of H α line impact polarization in solar flares
Authors: Firstova, N. M.; Polyakov, V. I.; Firstova, A. V.
Bibcode: 2014AstL...40..449F
Altcode:
  We present the results of studying the impact linear polarization of 32
  solar flares of X-ray classes C, M, and X (two flares) observed with the
  Large Solar Vacuum Telescope. It has turned out that there is evidence
  for impact polarization only in 13 of them. The newly obtained data
  have confirmed that the linear Stokes parameters are predominantly
  2-7%, while the spatial sizes of flaring points with nonzero Stokes
  parameters are small (1″-2″). Two features of the manifestation
  of impact polarization in flares revealed by these studies are of
  greatest interest: (1) at the two foot points of a single flare loop
  or an arcade of loops, both the H α intensity profiles and the Stokes
  profiles differ in behavior; (2) based on the H α line, we have found
  for the first time that the sign of the Stokes parameters changes not
  only across the flare ribbon but also with depth of the chromosphere.

Title: Hα Line Impact Linear Polarization Observed in the 23 July
    2002 Flare with the Large Solar Vacuum Telescope (LSVT)
Authors: Firstova, N. M.; Polyakov, V. I.; Firstova, A. V.
Bibcode: 2012SoPh..279..453F
Altcode:
  We present the results of studying the proton flare 2B/X4.8 on 23
  July 2002, observed with the Large Solar Vacuum Telescope (LSVT) at
  the Baikal Astrophysical Observatory in spectropolarimetric mode with
  high spatial and spectral resolution. We have found some evidence for
  Hα line impact linear polarization, predominantly during the initial
  moments of the flare. For the Hα line 606 cuts were made along the
  dispersion in 53 spectrograms, and a polarization signal was found
  more or less confidently in 60 cuts (13 spectrograms). Polarization
  was mainly observed in one of the kernels of the flare. A particular
  feature of this kernel was that the Hα line was observed to show
  a reversal in the central part of this kernel, which created a dip
  in the kernel center in the photometric cut. The size of these dips
  and the size of the sites with the linear polarization coincide and
  are equal to 3 - 6 arcsec. The maximum polarization degree in this
  kernel reached 15 %. The direction of the polarization in the kernel
  is radial, except for the first two frames, where the direction of
  the polarization was both radial and tangential. Furthermore, we found
  an analogy between the effects observed at the chromospheric level in
  this kernel (polarization and depression in Hα line) and the temporal
  variation of the HXR sources.

Title: Observing solar phenomenas with the large solar vacuum
    telescope
Authors: Firstova, N. M.; Polyakov, V. I.
Bibcode: 2011Ge&Ae..51..888F
Altcode:
  No abstract at ADS

Title: Studying instrumental linear polarization at the Large Solar
    Vacuum Telescope (LSVT)
Authors: Firstova, N. M.; Polyakov, V. I.; Skomorovsky, V. I.;
   Grigoriev, V. M.
Bibcode: 2009Ge&Ae..49..927F
Altcode:
  Impact linear polarization in solar flares is studied with the
  Large Solar Vacuum Telescope (LSVT) using the spectral polarimetric
  method. This method makes it possible to minimize the effect of
  instrumental polarization with an error of up to 10<SUP>-2</SUP> owing
  to the normalization of the spectral line intensity to the continuum
  spectrum intensity with negligible linear polarization. As a result,
  the Hα line intensity in two orthogonally polarized spectral stripes
  coincides in the absence of solar polarization. However, in the presence
  of linear polarization in a flare, the spectral polarimetric method does
  not rule out that the error can be present in determining the Stokes
  parameters Q and U because of their possible relative “leakage.”
  Linear instrumental polarization of LSVT has been performed using
  polaroid rotation before the major mirror. Twelve elements of a
  telescope matrix, characterizing linear polarization, have been
  determined. The usage of a matrix makes it possible to specify the
  observed Q and U values accurate to 10<SUP>-3</SUP> of their magnitude.

Title: Impact Linear Polarization on Impulsive Phase of Proton Flare
    Observations with High Spatial Resolution
Authors: Firstova, N. M.; Polyakov, V. I.; Firstova, A. V.
Bibcode: 2009ASPC..405..131F
Altcode:
  We describe the results of the observations of the 23 July 2002 2B/X4.8
  proton flare impulsive phase at the Irkutsk Large Solar Vacuum Telescope
  (LSVT) using the spectropolarimetric mode. 18 regions of the flare
  in the Hα line were observed with high spatial, spectroscopic and
  time resolution. In the six processed flare regions we obtained the
  evidence of impact linear polarization in the Hα line center. We
  noted that the general structure of the polarization profiles during
  the observation of a single flare region is kept in time. On the other
  hand, polarization across flare ribbons changes significantly. In all
  the flare regions we observed a deviation of the polarization peak
  position from the location of maximum intensity.

Title: Impact Linear Polarization of the H α Line Observed in a
    Proton Flare with the Irkutsk Large Solar Vacuum Telescope
Authors: Firstova, N. M.; Polyakov, V. I.; Firstova, A. V.
Bibcode: 2008SoPh..249...53F
Altcode: 2008SoPh..tmp...60F
  The impulsive phase of the 23 July 2002 2B/X4.8 proton flare with a
  classical two-ribbon structure was observed with the Irkutsk Large Solar
  Vacuum Telescope (LSVT) in spectropolarimetric mode, with high spatial,
  spectral, and time resolution. On the basis of 49 spectrograms and 1200
  spectral cuts across the flare ribbons, evidence for Hα line impact
  polarization has been obtained. A systematic change of the Stokes Q
  and U parameters has been detected across the ribbons for different
  flare regions measured with a scanning step of 0.85″. In the eastern
  side of the ribbons, the degree of polarization is 4 - 8%; its plane
  is oriented toward the solar disk center (radial direction). In the
  western side, the polarization degree runs up to 25%, and its plane is
  perpendicular to the disk center direction (tangential direction). A
  comparison of these results with hard X-ray data (RHESSI) allows us
  to conclude that high-energy electron beams reached the chromosphere
  during this flare. The observed changes of the direction of polarization
  and the vanishing polarization within the ribbons mean that, at the
  chromospheric level, the energy of electrons remaining in the beam is
  about 200 eV. A shift of the peak position of polarization relative to
  the intensity maximum in the ribbons may result from the inclination
  of the electron beam axis with respect to the solar surface.

Title: Hα Line Polarization in the Major Flare of 2002 July
    23. I. Observations and Data Analysis
Authors: Firstova, N. M.; Xu, Z.; Fang, C.
Bibcode: 2003ApJ...595L.131F
Altcode:
  On 2002 July 23, a major 2B/X4.8-class flare was observed in Hα lines
  with the Large Solar Vacuum Telescope of the Baikal Astrophysical
  Observatory using the spectropolarimetric method. Linear polarization
  of 3%-10% has been detected in Hα lines of the flare, particularly
  in the Hα lines with a central reversal. They are mainly radial on
  the solar disk and appear at the impulsive phase of hard X-ray and
  γ-ray bursts. The polarization changes its direction in a spatially
  limited small region (~4"-5") and within a short period of time
  (~10 s). Moreover, the linear polarization is limited to only some
  relatively small regions of the flare.

Title: Hα Line Polarization in the 2B/X4.8 Flare of 2002 July 23
Authors: Xu, Zhi; Firstova, N. M.; Chen, Qing-Rong; Fang, Cheng
Bibcode: 2003ChJAA...3..266X
Altcode:
  On 2002 July 23, a 2B/X4.8 flare was observed in the Hα line
  spectropolarimetrically by the Large Solar Vacuum Telescope of Baikal
  Astrophysical Observatory. Linear polarization of 3%-10% was detected in
  the Hα line, particularly where the line showed central reversal. The
  linear polarization is mainly radial on the solar disk and appears at
  the impulsive phase of the hard X-ray and γ-ray bursts. It is limited
  to some relatively small regions of the flare. The polarization in
  a limited small region (∼ 4''-5'') changed its direction within a
  short period of time (∼10 s)

Title: Measurement and processing of linear polarization in solar
    flares - a comparison of two methods
Authors: Kotrč, P.; Firstova, N. M.; Kashapova, L. K.; Kupryakov,
   Yu. A.
Bibcode: 2002ESASP.506..947K
Altcode: 2002svco.conf..947K; 2002ESPM...10..947K
  Linear polarization measurement in solar flares is discussed from the
  point of view of the processing technique. Usually, spectropolarimetric
  investigation of the linear polarization in solar flares is carried
  out for the line profiles. The results obtained by two methods
  (either processing of individual profiles or the whole spectral
  strips) are compared and applied to the observations obtained at the
  Large Solar Vacuum Telescope (the Baikal Astrophysial obseratory)
  and at the Ondřejov Multichannel Flare Spectrograph. The results
  obtained by the second method are comparable by accuracy with the
  results obtained by the first one. Moreover, it allows to check the
  instrumental polarization and the polarization behaviour in the nearby
  objects. However, the profile operating method allows to investigate
  the polarization effects along the dispersion more carefully.

Title: Observation of the linear polarization in the flare with a
    powerful surge
Authors: Firstova, N. M.; Kashapova, L. K.
Bibcode: 2002A&A...388L..17F
Altcode:
  An investigation of the linear polarization in the flare with a
  powerful surge revealed an unusual behavior of the Stokes parameter
  profiles along the dispersion. We discuss the probability that photons
  propagating from the flare and passing through the surge generate a
  linearly polarized radiation of the surge.

Title: The results of spectropolarimetric observations of solar
    flares followed by surge
Authors: Firstova, N. M.; Kashapova, L. K.
Bibcode: 2002ESASP.477..103F
Altcode: 2002scsw.conf..103F
  An investigation of the linear polarization in the June 29, 1999 flare
  with a powerful surge (the maximum velocity was about 160 km/sec)
  revealed an unusual behavior of the Stokes parameter profiles along the
  dispersion. We discuss the probability that photons propagating from
  the flare and passing through the surge generate a linearly polarized
  radiation of the surge.

Title: Investigation of He I 10 830 Å `Dark Points' at the Sayan
    Solar Observatory and the Baikal Astrophysical Observatory
Authors: Skomorovsky, V. I.; Firstova, N. M.; Kashapova, L. K.;
   Kushtal, G. I.; Boulatov, A. V.
Bibcode: 2001SoPh..199...37S
Altcode:
  A new two-bandpass birefringent filter has been produced at
  ISTP, Irkutsk for the investigation of the fine structure of the
  chromosphere. One filter passband is centered on the He i 10 830 Å
  line, the second one is centered on Hα. The FWHM of the He i 10 830 Å
  passband is 0.46 Å and of the Hα passband is 0.3 Å. A large number of
  filtergrams were obtained with the filter at the Sayan observatory. At
  the same time, spectral observations with high spatial and spectral
  resolution were carried out by the large solar vacuum telescope at the
  Baikal Observatory. We selected 29 `dark point' spectra with sizes from
  2'' to 13'', as well as `dark points' on the filtergrams. Comparison of
  spectrograms and filtergrams has shown a good agreement of their size
  and intensity in relation with the surrounding chromosphere as well
  as the absence of primary line-of-sight velocities in both observation
  types. From spectral observations, the depth of 10 830 Å is over 30%
  for some `dark points', and the FWHM is more than 1 Å. He i 10 830 Å
  line profiles in `dark points' are more deep and wide than in quiet
  regions. The optical depth of the chromosphere in `dark points' is
  estimated. Comparison with the unperturbed chromosphere showed that
  `dark points' in He i 10 830 Å are more optically thin than the
  nearby chromosphere.

Title: The Today's Investigations on Large Solar Vacuum Telescope
Authors: Skomorovsky, V. I.; Firstova, N. M.; Kashapova, L. K.;
   Firstova, A. V.; Kushtal, G. I.
Bibcode: 2001AGM....18.P221S
Altcode:
  The contribution presents the prospective observations obtained with
  the Large Solar Vacuum Telescope (Baikal astrophysical observatory,
  Irkutsk) from 1997 after its re-equipment by CCD-camera. During the
  latest years we carried out basically the spectropolarimetric Hα
  observations of the emission objects of different sizes from the solar
  flares to the Ellerman bombs. The flares followed by a surges have
  aroused a special interest. The observations and preliminary results are
  shown. The Ellerman bombs or moustaches were devoted much attention. We
  obtained the extensive observational data( more than 200 objects) and
  the various mechanisms of their arising have been analyzed. Besides
  the investigation of the linear polarization in Hα line the spectral
  observations in IR region (HeI 10830 Å line) were carried out. Also
  we obtain the observation of the pores in the several Fe lines for the
  latest two years. This work was supported by Russian Foundation for
  Basic Research grants 00-02-16068-a and 01-02-06203. Thanks are also
  due the State Support of Leading Scientific Schools of the Russian
  Federation grant 00-15-96659 and the State Scientific and Technical
  Program ``Astronomy'' for their support.

Title: First-order adaptive system for correction of images in solar
    ground-based telescopes
Authors: Antoshkin, Leonid V.; Borovik, A. B.; Botygina, Nina N.;
   Bulatov, Alexei V.; Emaleev, Oleg N.; Firstova, N. M.; Fortes, Boris
   V.; Grigoryev, Victor M.; Kovadlo, P. G.; Lavrinova, L. N.; Lukin,
   Vladimir P.; Petrov, A. I.; Skomorovsky, Valery I.; Yankov, A. P.
Bibcode: 2000SPIE.4007..232A
Altcode:
  The possibility of applying adaptive-optics devices to ground- based
  solar astronomy and high-resolution spectroscopy is considered. Due
  to atmospheric turbulence the resolution of ground-based solar
  telescopes are limited to 1 arcsec on the average with short period
  of subarcsecond resolution at good sites. Application of adaptive
  correction is a ground-based telescope to improve image quality is
  possible to improve whole performance of telescope to obtain images
  with resolution about 0.3' and to improve resolution for spectral
  measurements of the Sun. Adaptive Optics represent a visible tool for
  increasing the resolution of ground-based telescopes to the level that
  will be needed to understand the physical processes occurring on the
  Sun. An experimental adaptive- optics system for image stabilization is
  described, as well as the results of its tests. Different ways of the
  further development of the adaptive-optics system for use in the Big
  Solar Vacuum Telescope (BSVT) of the Baikal Astrophysical Observatory
  are discussed.

Title: The linear polarization in moustaches
Authors: Firstova, N. M.; Boulatov, A. V.; Kashapova, L. K.
Bibcode: 1999ASSL..243..451F
Altcode: 1999sopo.conf..451F
  No abstract at ADS

Title: A spectropolarimetric study of the Hα radiation from
    Ellerman bombs.
Authors: Kazantsev, S. A.; Firstova, N. M.; Kashapova, L. K.; Bulatov,
   A. V.; Petrashen', A. G.
Bibcode: 1998RuPhJ..41.1258K
Altcode:
  Polarization data are given for three whiskers recorded with the
  large solar vacuum telescope at Baikal Observatory, Institute of
  Solar-Terrestrial Physics, Russian Academy of Sciences. The observed
  degree of polarization varies from 2 to 13%. The direction of the
  polarization plane for the medium intensity whisker was tangential,
  while that for the weakest one was radial. The brightest whisker had
  a polarization plane direction close to radial at the center of the
  line but tangential at the flanks. It is assumed that the polarization
  is due to impact excitation of a hydrogen-atom ensemble in the solar
  chromosphere by an electron beam, and estimates are made of the
  beam energy.

Title: Spectropolarimetric studies of H<SUB> alpha </SUB> emission
in "solar moustaches": Observations and calculation of the Stokes
    parameters
Authors: Kazantsev, S. A.; Firstova, N. M.; Kashapova, L. K.; Bulatov,
   A. V.; Petrashen', A. G.; Henoux, J. -C.
Bibcode: 1998ARep...42..702K
Altcode:
  The results of spectropolarimetric observations of three solar
  `moustaches' carried out on the Large Vacuum Solar Telescope of
  Baikal Observatory of the Institute of Solar-Terrestrial Physics are
  presented. The observed degree of polarization varies from 2-13%. The
  direction of the plane of polarization for a moustache with moderate
  intensity is tangential, and is radial for the weakest moustache. In
  the brightest moustache, the plane of polarization is close to radial
  at the line center, and is tangential in the wings.

Title: Spectropolarimetric studies of H<SUB> alpha </SUB> emission in
"solar moustaches": Energy of the excited electron beam
Authors: Kazantsev, S. A.; Firstova, N. M.; Petrashen', A. G.; Henoux,
   J. =C.
Bibcode: 1998ARep...42..707K
Altcode:
  Spectropolarimetric observations of the Hα emission of `solar
  moustaches' are used to estimate the energy of the beam of electrons
  that is assumed to give rise to the observed polarization during
  its shock excitation of an ensemble of hydrogen atoms in the solar
  chromosphere.

Title: Spectroscopolarimetric Sensing of Energy Deposition Into the
    Chromosphere during Solar Flares - I. Observations
Authors: Firstova, N. M.; Hénoux, J. -C.; Kazantsev, S. A.; Bulatov,
   A. V.
Bibcode: 1997SoPh..171..123F
Altcode:
  Measurements of linear polarization in hydrogen Hα and Hβ lines,
  made with the Large Solar Vacuum Telescope of Baikal Astrophysical
  Observatory and Automated Solar Telescope of Sayan Solar Observatory,
  affiliated with the Russian Institute of Solar and Terrestrial Physics,
  are reported in this paper. Short-term polarization associated with
  solar flares is found to be present in active regions. There is
  a significant tendency for the Hα polarization vector to be radial,
  i.e., in the flare-to-disk-center direction. This polarization may be
  due to atmospheric bombardment by hecta keV protons. On the other hand,
  the polarization vector is found to be perpendicular to the radial
  direction at some locations where the line profile has a typical
  mustache shape suggesting a bombardment by energetic electrons. The
  Hβ line is also linearly polarized. However, no preferential direction
  of polarization is found in this line, which is formed more deeply in
  the solar atmosphere.

Title: Spectropolarimetry of solar flare based on measurements of
    the H<SUB> beta </SUB> hydrogen line
Authors: Kazantsev, S. A.; Petrashen', A. G.; Firstova, N. M.; Henoux,
   J. -C.
Bibcode: 1996OptSp..80..635K
Altcode:
  No abstract at ADS

Title: Determination of energy transfer to the chromospheric region of
    solar flare on the basis of spectropolarimetric data on hydrogen lines
Authors: Kazantsev, S. A.; Petrashen', A. G.; Firstova, N. M.; Enu,
   Zh. -K.
Bibcode: 1996OptSp..80..532K
Altcode:
  No abstract at ADS

Title: Characteristics of the Linear Polarization Observed in the
    16 May 1991 Solar Flare
Authors: Firstova, N. M.; Boulatov, A. V.
Bibcode: 1996SoPh..164..361F
Altcode:
  In a search for linear polarization effects, 37 profiles of the
  H<SUB>α</SUB> line emitted in the 16 May 1991 flare have been
  analyzed. Linear polarization is clearly present in the central
  part of line. On average, the degree of polarization is 7 %, but it
  reaches 20 % in regions with lower H<SUB>ga</SUB> emission. Generally
  the orientation of the plane of polarization coincides with the flare
  to disk center direction, except for sections where the H<SUB>ga</SUB>
  line has the characteristic form observed in moustaches. We believe that
  the linear polarization observed in the 16 May 1991 flare was caused
  by bombardment of the chromosphere by beams of accelerated particles,
  protons in the main part of the flare and electrons at locations where
  the H<SUB>ga</SUB> line has the characteristic moustache structure.

Title: The Large Solar Vacuum Telescope: the Optical System, and
    First Spectral Observations
Authors: Skomorovsky, V. I.; Firstova, N. M.
Bibcode: 1996SoPh..163..209S
Altcode:
  The performance of the optics of the Large Solar Vacuum Telescope
  (LSVT) and examples of the spectrograms taken with the spectrograph are
  presented. A new pneumo-mechanical support system for the siderostat
  mirror and monitoring system of the telescope optics is described.

Title: Determination of the energy of the proton beam formed in a
    solar flare on the basis of spectropolarimetric data
Authors: Kazantsev, S. A.; Firstova, N. M.; Petrashen', A. G.; Henoux,
   J. -C.; Bulatov, A. V.
Bibcode: 1995OptSp..78..655K
Altcode:
  No abstract at ADS

Title: Spectropolarimetric determination of the energy contribution
    to the optically active region of the chromosphere
Authors: Kazantsev, S. A.; Petrashen, A. G.; Firstova, N. M.; Hénoux,
   J. C.
Bibcode: 1993OptSp..75..382K
Altcode:
  No abstract at ADS

Title: Possibilities of spectropolarimetrically studying eruptive
    formations in the solar atmosphere
Authors: Kazantsev, S. A.; Firstova, N. M.; Gubin, A. V.; Lankevich,
   N. A.
Bibcode: 1991OptSp..70..580K
Altcode:
  No abstract at ADS

Title: Observational aspects of the study of plasma turbulence in
    solar flares.
Authors: Firstova, N. M.
Bibcode: 1990JQSRT..44..177F
Altcode:
  Using two techniques (the polarization method and the Baranger-Mozer
  method) a study has been made of plasma turbulence in solar emission
  features. The study suggests the conclusion that the 0.02 - 0.03 plasma
  turbulence level (E = 1 - 2 kV cm<SUP>-1</SUP>) seems to be the highest
  achieved in flares.

Title: On the Presence of High-frequency Turbulent Electric Fields
    in the August 7, 1960 Flare
Authors: Firstova, N. M.; Heinzel, P.; Kotrc, P.
Bibcode: 1990BAICz..41...88F
Altcode:
  According to Oks (1978), the wings of some hydrogen Balmer lines
  observed in the spectrum of the moustache-like flare of August 7,
  1960 do exhibit theoretically predicted dips, which should indicate
  the presence of Langmuir turbulence. However, these features are rather
  subtle and thus several difficulties arise if one tries to identify them
  in the noisy spectra with typically many blends. Moreover, the Balmer
  profiles used for Oks' analysis were already 'filtered' in a special
  manner, which strongly affects the results. In view of these problems,
  consideration is given to whether these dips in this particular flare
  were real, starting with newly obtained microphotometric records. Using
  the same lines as Oks (i.e., H7, H8, H11-13), together with H14,
  none of the expected dips in the line wings were identified. All
  observational aspects of this analysis are discussed in detail, and
  new special observations are proposed. The role of electron density
  variations within the flare volume is also briefly discussed.

Title: A Search for a Plasma Turbulence in the Flare of September 15,
1981, 00:09 UT
Authors: Firstova, N. M.; Kotrc, P.
Bibcode: 1987BAICz..38..257F
Altcode:
  The linear polarization in the H-alpha and H-beta lines in the flare
  of Sept. 15, 1981, is studied by a photographic method which enables
  instrumental polarization to be eliminated. Considerable values of
  the degree of polarization occur in the cores of the lines, at some
  points as much as 17 percent. However, an objective analysis of all
  the profiles indicates that the polarization in this flare cannot be
  demonstrated as the degree of polarization does not exceed, on the
  average, the inaccuracy of the photographic method used. A blue shift
  corresponding to the velocities -2.5 km/s and -1.3 km/s has been found
  in the cores of the H-alpha and H-beta lines, respectively. The blue
  shift changes into red at about the full width of the half maximum of
  the lines.

Title: An Investigation of the Linear Polarization in Emission
    Features of Active Regions
Authors: Firstova, N. M.
Bibcode: 1986SoPh..103...11F
Altcode:
  A study has been made of linear polarization in `moustaches' using
  the Hα and Hβ lines. A Wollaston prism and an achromatic λ/2-plate
  were employed in the study. In the course of the observations, the
  major axis of the plate was placed at 0° and 22°.5 with respect to
  the horizontal axis of the installation. The Stokes parameters J, Q,
  and U were recorded, thus enabling the degree of polarization and
  the field azimuth to be determined. During the first three minutes
  of the existence of the moustaches, the two lines revealed a linear
  polarization of about 7% located at the center of the lines. No
  polarization was found during the later stage of the moustaches'
  lifetimes. Whenever the linear polarization is present, there is a
  tendency for the polarization to decrease rapidly, in accompaniment
  of a turning of the azimuth. Several mechanisms for interpreting
  the polarization observed in the moustaches are examined. Some
  suggestions are made in support of the excitation of hydrogen atoms
  in the moustaches initiated by a high-energy electron flux or vertical
  heat conduction.

Title: Observational aspects in investigating the plasma turbulence
    in solarflares.
Authors: Firstova, N. M.
Bibcode: 1986psf..conf...65F
Altcode:
  No abstract at ADS

Title: An evaluation of the possibility of studying flare plasma
    turbulence using the satellites of He i line forbidden components
Authors: Firstova, N. M.
Bibcode: 1984SoPh...90..269F
Altcode:
  Using the Baranger-Mozer method, we explore the possibility of
  diagnosing the flare plasma of forbidden HeI lines, that permits
  the determination of the plasma oscillation frequency and noise
  level. Examination of the HeI lines observed in solar flare has led us
  to conclude that: the appearance of satellites of forbidden components
  in the flares spectrum, due to turbulent electric fields, is the most
  probable for HeI 3819.606 Å lines;

Title: Review of Observational Techniques and Data on Turbulent
    Electric Fields in Solar Flares
Authors: Firstova, N. M.
Bibcode: 1984IGAFS..68...31F
Altcode:
  No abstract at ADS

Title: The Evaluation of the Possible Investigation of Flare Plasma
    Turbulence Using Satellites of Forbidden Components of the Hei Lines
Authors: Firstova, N. M.
Bibcode: 1983IGAFS..65..194F
Altcode:
  No abstract at ADS

Title: Ratio of maximum intensities of CA II H and K lines in
    umbral flashes
Authors: Firstova, N. M.
Bibcode: 1980AZh....57..666F
Altcode:
  No abstract at ADS

Title: Ratio of Maximum Intensities of CAII H and K Lines in Umbral
    Flashes
Authors: Firstova, N. M.
Bibcode: 1980SvA....24..384F
Altcode:
  No abstract at ADS

Title: Concerning the Big Solar Vacuum Telescope Spectrograph
    Scheme Choosing
Authors: Firstova, N. M.
Bibcode: 1980IGAFS..52..122F
Altcode:
  No abstract at ADS

Title: Variation of sunspot umbra sizes with height.
Authors: Firstova, N. M.; Turova, I. P.
Bibcode: 1979IGAFS..45...49F
Altcode:
  No abstract at ADS

Title: Oscillations regime in the chromosphere above a large sunspot
    umbra.
Authors: Teplitskaya, R. B.; Turova, I. P.; Firstova, N. M.
Bibcode: 1979IGAFS..49...21T
Altcode:
  No abstract at ADS

Title: Bright emission in H and K Ca II lines in a sunspot umbra.
Authors: Firstova, N. M.
Bibcode: 1978BSolD1978...77F
Altcode:
  No abstract at ADS

Title: Shapes and centre-to-limb variation of the H and K lines in
    sunspot umbrae.
Authors: Teplitskaia, R. B.; Firstova, N. M.
Bibcode: 1976SoPh...48..103T
Altcode:
  The shapes of the Ca II H and K lines in sunspot umbral spectra
  vary from single asymmetric peaks near the centre of the disk to
  almost symmetric double peaks at the limb. In addition, there are
  other differences in the behaviour of both H and K lines in sunspots
  compared to the quiet Sun. The whole complex of the phenomena observed
  can not be explained by large scale chromosphere motions. Instead, a
  satisfactory model reproducing in detail peculiarities of the umbral
  emission reversals contains a cloud of emitting and absorbing gas
  located above the chromosphere, which flows into the sunspot. The
  radiation field parameters in such a cloud are consistent with the
  concept of weak quiescent prominences above the umbra.

Title: The sphape of the H and K Ca II line profiles in the spectra
    of sunspot umbrae and its center-to-limb variation.
Authors: Teplitskaya, R. B.; Firstova, N. M.
Bibcode: 1976fsp..conf...84T
Altcode:
  No abstract at ADS

Title: Extraction of scattered light on sunspot spectrograms obtained
    by means of a Wollaston prism.
Authors: Firstova, N. M.; Kuklin, G. V.
Bibcode: 1973BSolD1973...94F
Altcode:
  No abstract at ADS

Title: Dependence of temperature on the magnetic field intensity in
    the region of a sunspot.
Authors: Firstova, N. M.
Bibcode: 1973BSolD1973...91F
Altcode:
  No abstract at ADS

