explanation      blue bibcodes open ADS page with paths to full text
Author name code: kitai
ADS astronomy entries on 2022-09-14
=author:"Kitai, R." 

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Title: Magnetic field structures associated with chromospheric
    heating in a plage region
Authors: Anan, T.; Schad, T.; Kitai, R.; Dima, G.; Jaeggli, S.;
   Collados, M.; Dominguez-Tagle, C.; Kleint, L.
2021AAS...23821222A    Altcode:
  The strongest quasi-steady heating in the solar atmosphere occurs in
  the active chromosphere and in particular within plage regions. Our
  aim is to investigate the relation between magnetic structures and
  the signatures of heating in the plage regions so as to clarify what
  mechanisms are at work. We observed a plage region in NOAA active
  region 12723 in the near infrared He I triplet and Si I 1082.7 nm
  on 2018 October 3 using the Integral Field Unit mode of the GREGOR
  Infrared Spectrograph (GRIS) installed at the GREGOR telescope. At the
  same time, the Interface Region Imaging Spectrograph (IRIS) obtained
  spectra in the ultra-violet Mg II h & k doublet emitted from the
  same region. We applied the HAnle and ZEeman Light v2.0 inversion
  code (HAZEL v2.0) to the GRIS data to infer the photospheric and
  chromospheric magnetic field. We find that the radiative flux of the Mg
  II was large between patches of strong magnetic field strength in the
  photosphere, or at edges of the magnetic patches. On the other hand,
  the spatial correspondences between the Mg II flux and the magnetic
  field strength in the chromosphere and between the Mg II flux and the
  electric current are not so clear. In conclusion, chromospheric heatings
  in the plage region can be related to magnetic field perturbations
  produced by interactions of magnetic flux tubes.

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Title: Development of the Universal Tunable Filter and High-resolution
    Imaging Observation with the Fuxian Solar Observatory
Authors: Hagino, M.; Ichimoto, K.; Ueno, S.; Kimura, G.; Otsuji, K.;
   Kitai, R.; Zhong, L.; Xu, Z.; Shinoda, K.; Hara, H.; Suematsu, Y.;
   Shimizu, T.
2016ASPC..504..103H    Altcode:
  We have developed a new narrow-band universal tunable filter to perform
  imaging spectroscopy of the solar chromosphere. The development stage
  of the filter has been almost finished and we shifted to the scientific
  observation phase by using large grand-based telescopes. Using the
  filter, a series of high-resolution images were obtained with the 1m
  vacuum solar telescope at the Fuxian Solar Observatory. We succeeded in
  observing several flares and fine structures of the chromospheric layer.

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Title: Evolution and Flare Activity of δ -Sunspots in Cycle 23
Authors: Takizawa, K.; Kitai, R.
2015SoPh..290.2093T    Altcode: 2015arXiv150706453T; 2015SoPh..tmp...96T
  The emergence and magnetic evolution of solar active regions (ARs)
  of β γ δ -type, which are known to be highly flare-productive,
  were studied with SOHO/MDI data in Cycle 23. We selected 31 ARs that
  can be observed from their birth phase as unbiased samples for our
  study. From the analysis of the magnetic topology (twist and writhe),
  we obtained the following results: i) Emerging β γ δ ARs can be
  classified into three topological types as quasi-β , writhed, and
  top-to-top. ii) Of these, the writhed and top-to-top types tend to show
  high flare activity. iii) As the signs of twist and writhe agree with
  each other in most cases of the writhed type (12 cases out of 13),
  we propose a magnetic model in which the emerging flux regions in a
  β γ δ AR are not separated, but are united as a single structure
  below the solar surface. iv) Almost all the writhed-type ARs have
  downward knotted structures in the middle part of the magnetic flux
  tube. This is probably the essential property of β γ δ ARs. v) The
  flare activity of β γ δ ARs is highly correlated not only with the
  sunspot area, but also with the magnetic complexity. vi) We suggest
  that there is a possible scaling-law between the flare index and the
  maximum umbral area.

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Title: Morphological model for quadrupolar δ sunspots
Authors: Takizawa, K.; Kitai, R.
2014AGUFMSH41B4136T    Altcode:
  Sunspot with umbrae of opposite polarity within a single common
  penumbra are called δ-spot group (Kunzel, 1960). It has been well
  known that major flares almost always occur in active region with
  δ-configuration. Hence, to investigate the formation and evolution
  of δ-configuration is a key in understanding the major flare
  activities. However, for the case of δ-spot, emerging flux regions
  (EFRs) combine intricately to each other. Therefore it is so difficult
  to decipher the relations between multiple EFRs. To clearly follow the
  development of the ARs, we should select the ARs which can be observed
  from the initial emerging stage. Emergence and magnetic evolution
  of solar active regions (ARs) of βγδ-type, which are known to be
  highly flare active (Sammis 2000), were studied with the SOHO/MDI data
  in the solar cycle 23. 31 ARs, which can be seen from the birth phase,
  were selected as unbiased samples of our study. From our analysis, we
  found that successive birth of two emerging flux regions, spatially
  separated to each other in east-west direction as a series, forming
  a quadrupolar magnetic configuration, is a typical way of initial
  development of βγδ regions. The δ-configuration was formed by
  following polarity of western EFR with preceding polarity of eastern
  EFR. We found 11ARs of quadrupolar type among the sampled 31 ARs. In
  this work, we propose a plausible model for the quadrupolar type
  δ-spots as a simple magnetic tube of helical structure, which have
  downward knot in the mid portion of the flux tube. In nine cases out
  of 11, the characteristics of the magnetic helicity signs, i.e. the
  signs of twist and writhe, are consistent with our model.

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Title: Within the International Collaboration CHAIN: a Summary of
    Events Observed with Flare Monitoring Telescope (FMT) in Peru
Authors: Ishitsuka, J.; Asai, A.; Morita, S.; Terrazas, R.; Cabezas,
   D.; Gutierrez, V.; Martinez, L.; Buleje, Y.; Loayza, R.; Nakamura,
   N.; Takasao, S.; Yoshinaga, Y.; Hillier, A.; Otsuji, K.; Shibata, K.;
   Ishitsuka, M.; Ueno, S.; Kitai, R.; Ishii, T.; Ichimoto, K.; Nagata,
   S.; Narukage, N.
2014SunGe...9...85I    Altcode:
  In 2008 we inaugurated the new Solar Observatory in collaboration with
  Faculty of Sciences of San Luis Gonzaga de Ica National University,
  300 km south of Lima. In March of 2010 a Flare Monitoring Telescope
  of Hida Observatory of Kyoto University arrived to Ica, part of CHAIN
  Project (Continuous H-alpha Imaging Network). In October of the same
  year we hosted the First FMT Workshop in Ica, then in July of 2011 the
  Second FMT Workshop was opened. Since that we are focused on two events
  registered by FMT in Peru to publish results. FMT is a good tool to
  introduce young people from universities into scientific knowledge;
  it is good also for education in Solar Physics and outreach. Details
  of this successful collaboration will be explained in this presentation.

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Title: Magnetic helicity transported by flux emergence and shuffling
    motions
Authors: Zhang, Y.; Kitai, R.; Takizawa, K.
2013IAUS..294..319Z    Altcode:
  Magnetic helicity can be transported from sub-photosphere into corona by
  the emergence of helical magnetic field lines and the shuffling motions
  of foot-points of pre-existing coronal field lines. Active region NOAA
  10930 was observed by SP and NFI of SOT on board Hinode when it pass
  through the solar meridian. Based on these observations, we calculate
  magnetic helicity flow of both terms, by regarding Doppler velocity
  as normal velocity. The results are compared with which calculated by
  method proposed by Zhang et. al. (2012). Our results show that helicity
  injection maps calculated by both methods have similar distribution
  and the integration values have the same magnitude.

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Title: Prominent Photospheric Downflows on Magnetic Neutral Line in
    a Delta-Type Sunspot
Authors: Takizawa, K.; Kitai, R.; Zhang, Y.
2012SoPh..281..599T    Altcode: 2012SoPh..tmp..219T
  It is known that δ-type sunspot groups have a high flare productivity
  and produce strong flares. In particular, βγδ type sunspots are the
  most active type of all. A βγδ active region NOAA 9957 with frequent
  flux cancellations but without any marked flare activity during its
  decay phase was studied in this work. Using SOHO/MDI Dopplergrams and
  magnetograms, we detected continuous prominent downflow motions of 1500
  - 1700 m s<SUP>−1</SUP> for several hours on the magnetic neutral
  line in this region. In the downflow region, penumbral structures were
  observed to decay. We will interpret and discuss the phenomenon as a
  case of submergence of the magnetic flux.

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Title: Persistent Circulating Motion in a Sunspot Umbra
Authors: Katsukawa, Y.; Kitai, R.; Watanabe, H.
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.

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Title: Spicule Dynamics over Plage Region
Authors: Anan, T.; Kitai, R.; Hillier, A.; Kawate, T.; Ichimoto, K.;
   Shibata, K.
2012ASPC..454...91A    Altcode:
  We have studied spicular jets over a plage region and derived their
  dynamic characteristics using Hinode Solar Optical Telescope (SOT)
  high-resolution Ca II H images. We have identified 169 spicules over
  the target plage. This sample size permits us to derive statistically
  reliable results regarding spicular dynamics. The properties of plage
  spicules can be summarized as follows: (1) In a plage area, we clearly
  identify spicular jet features. (2) They are shorter in length than
  the quiet-region limb spicules, and follow ballistic motion under
  constant deceleration. (3) The majority (80%) of the plage spicules
  show a full rise and retreat (which we call ‘parabolic’ spicules),
  while 10% of them fade out without a complete retreat phase(which we
  call ‘fade out’ spicules). (4) The deceleration of the spicule is
  proportional to the velocity of ejection (i.e. the initial velocity).

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Title: Chromospheric Anemone Jets Observed with Hinode/SOT and Hida
    Ca II Spectroheliograph
Authors: Morita, S.; Shibata, K.; Ueno, S.; Ichimoto, K.; Kitai, R.;
   Otsuji, K.
2012ASPC..454...95M    Altcode:
  We present the first simultaneous observations of chromospheric
  “anemone” jets in active regions with the Ca II H broadband
  filetergram on the Hinode/SOT and with the Ca II K spetroheliogram on
  the Domeless Solar Telescope (DST) at the Hida Observatory. During
  coordinated observation period, 9 chromospheric anemone jets were
  simultaneously observed with the two instruments. These observations
  revealed: (1) the jets are generated in the low chromosphere because
  these cannot be seen in Ca II K<SUB>3</SUB>, (2) these jets are
  associated with mixed polarity regions which are either small emerging
  flux regions or moving magnetic features, (3) the Ca II K line often
  show red or blue asymmetry in K<SUB>2</SUB>/K<SUB>1</SUB> component;
  the footpoint of the jets associated with emerging flux regions often
  show red asymmetry (2-16 km s<SUP>-1</SUP>), while the one with moving
  magnetic features show blue asymmetry (∼5 km s<SUP>-1</SUP>). The
  magnetic cancellations were observed at the footpoint of the jets. The
  canceling rates are of order of 10<SUP>16</SUP> Mx s<SUP>-1</SUP>, and
  the resulting magnetic energy release rate (1.1-10)×10<SUP>24</SUP> erg
  s<SUP>-1</SUP>, with the total energy release (1-13)×10<SUP>26</SUP>
  erg for the duration of the magnetic cancellations, ∼130 s. These
  are comparable to the estimated total energy, ∼10<SUP>26</SUP> erg,
  in a single chromospheric anemone jet.

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Title: Magnetic Helicity Transported by Flux Emergence and Shuffling
    Motions in Solar Active Region NOAA 10930
Authors: Zhang, Y.; Kitai, R.; Takizawa, K.
2012ApJ...751...85Z    Altcode: 2012arXiv1203.2096Z
  We present a new methodology which can determine magnetic helicity
  transport by the passage of helical magnetic field lines from the
  sub-photosphere and the shuffling motions of footpoints of preexisting
  coronal field lines separately. It is well known that only the
  velocity component, which is perpendicular to the magnetic field (υ
  <SUB>B </SUB>), has contributed to the helicity accumulation. Here,
  we demonstrate that υ <SUB>B </SUB> can be deduced from a horizontal
  motion and vector magnetograms under a simple relation of υ <SUB> t
  </SUB> = μ <SUB> t </SUB> + (υ<SUB> n </SUB>/B<SUB>n</SUB> ) B <SUB>
  t </SUB>, as suggested by Démoulin &amp; Berger. Then after dividing
  υ <SUB>B </SUB> into two components, as one is tangential and the
  other is normal to the solar surface, we can determine both terms of
  helicity transport. Active region (AR) NOAA 10930 is analyzed as an
  example during its solar disk center passage by using data obtained
  by the Spectropolarimeter and the Narrowband Filter Imager of Solar
  Optical Telescope on board Hinode. We find that in our calculation
  the helicity injection by flux emergence and shuffling motions have
  the same sign. During the period we studied, the main contribution
  of helicity accumulation comes from the flux emergence effect, while
  the dynamic transient evolution comes from the shuffling motions
  effect. Our observational results further indicate that for this AR
  the apparent rotational motion in the following sunspot is the real
  shuffling motions on the solar surface.

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Title: Ellerman Bomb as a Manifestation of Chromospheric Fine Scale
    Activity
Authors: Kitai, R.
2012ASPC..456...81K    Altcode:
  Observational and theoretical studies on Ellerman bombs are briefly
  reviewed. Including the recent results by high spatial resolution
  observation done with Hinode/SOT and so on, we will summarize our
  present understanding of Ellerman bomb phenomenon as a chromospheric
  fine scale activity driven by successive and intermittent magnetic
  reconnection in deeply seated locations of lower chromospheres or in
  the upper photosphere.

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Title: Properties of Umbral Dots as Measured from the New Solar
    Telescope Data and MHD Simulations
Authors: Kilcik, A.; Yurchyshyn, V. B.; Rempel, M.; Abramenko, V.;
   Kitai, R.; Goode, P. R.; Cao, W.; Watanabe, H.
2012ApJ...745..163K    Altcode: 2011arXiv1111.3997K
  We studied bright umbral dots (UDs) detected in a moderate size sunspot
  and compared their statistical properties to recent MHD models. The
  study is based on high-resolution data recorded by the New Solar
  Telescope at the Big Bear Solar Observatory and three-dimensional (3D)
  MHD simulations of sunspots. Observed UDs, living longer than 150 s,
  were detected and tracked in a 46 minute long data set, using an
  automatic detection code. A total of 1553 (620) UDs were detected
  in the photospheric (low chromospheric) data. Our main findings
  are (1) none of the analyzed UDs is precisely circular, (2) the
  diameter-intensity relationship only holds in bright umbral areas, and
  (3) UD velocities are inversely related to their lifetime. While nearly
  all photospheric UDs can be identified in the low chromospheric images,
  some small closely spaced UDs appear in the low chromosphere as a single
  cluster. Slow-moving and long-living UDs seem to exist in both the low
  chromosphere and photosphere, while fast-moving and short-living UDs
  are mainly detected in the photospheric images. Comparison to the 3D
  MHD simulations showed that both types of UDs display, on average, very
  similar statistical characteristics. However, (1) the average number
  of observed UDs per unit area is smaller than that of the model UDs,
  and (2) on average, the diameter of model UDs is slightly larger than
  that of observed ones.

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Title: Properties of Umbral Dots as Measured from the New Solar
    Telescope Data and MHD Simulations
Authors: Yurchyshyn, V.; Kilcik, A.; Rempel, M.; Abramenko, V.; Kitai,
   R.; Goode, P. R.; Cao, W.; Watanabe, H.
2011sdmi.confE..86Y    Altcode:
  We studied bright umbral dots (UDs) detected in the main sunspot
  of AR NOAA 11108 and compare their statistical properties to a
  state-of-the-art MHD model of a sunspot. The study is based on
  high resolution data recorded on September 20, 2010 by the New Solar
  Telescope (NST) at Big Bear Solar Observatory and 3D MHD simulations of
  sunspots. The 46 min data set included photospheric (0.3nm TiO filter
  centered at 705.7 nm) and chromospheric (0.025nm Hα Lyot filter)
  adaptive optics corrected and speckle reconstructed images. Bright
  UDs, living longer than 150 s, were detected and tracked using an
  automatic UD detection code. Total 1553 (620) UDs were detected
  in the photospheric (chromospheric) data. Our main findings are:
  i) none of the analyzed UDs is of an exact circular shape, ii) the
  diameter-intensity relationship only works for bright umbral areas, and
  iii) UD velocities inversely related to their life time. Comparison of
  photospheric and chromospheric data showed that nearly all photospheric
  UDs can be identified in the chromospheric images. However, it appears
  that some small closely spaced UDs appear in the chromospheric images
  as a single cluster, which may lead to the underestimation of the total
  number of detected chromospheric UDs. Also, while slow moving and long
  living UDs seem to exist in both chromosphere and photosphere, fast
  moving and short living ones are detected mainly in the photospheric
  images. Comparison of model and observed data shows that both types
  of UDs display very similar statistical characteristics. The main
  difference between parameters of model and observed UDs is that i)
  the average number of observed UDs per unit area is smaller than that
  of the model UDs, and ii) on average, the diameter of model UDs is
  slightly larger than that of observed ones.

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Title: Continuous H-alpha Imaging Network Project (CHAIN) with Ground-
    based Solar Telescopes for Space Weather Research
Authors: Ueno, S.; Shibata, K.; Ichimoto, K.; Kitai, R.; Nagata, S.;
   Kimura, G.; Nakatani, Y.
2010AfrSk..14...17U    Altcode:
  No abstract at ADS

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Title: Solar Plages: Observational Study of Their Chromospheric
    Heating and Spicular Mass Ejections
Authors: Kitai, R.; Hashimoto, Y.; Anan, T.; Matsumoto, T.; Kawate,
   T.; Watanabe, H.; Otsuji, K.; Nakamura, T.; Nishizuka, N.; Nishida,
   K.; Ueno, S.; Nagata, S.; Shibata, K.
2009ASPC..415...19K    Altcode:
  We investigated the chromospheric dynamics of plage area. From our
  spectroscopic analysis of the CaII K line, we have found that their
  periodic variations are due to the propagation of acoustic waves from
  the lower layers. Another observational work on Hinode CaII H images,
  gave us a new result that there are numerous spicular jets in plage
  area, thanks to the stable observing condition of Hinode. The present
  paper is an extended abstract of our works which will be published
  fully in our future papers.

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Title: Magnetic Structure of Umbral Dots with SOT SP
Authors: Watanabe, H.; Kitai, R.; Ichimoto, K.; Katsukawa, Y.
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.

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Title: The tandem Fabry Perot Full-Disk Solar Vector Magnetogram
    system for the Solar Magnetic Activity Research Telescope (SMART)
Authors: Otsuji, K.; Nagata, S.; Ueno, S.; Kitai, R.; Kimura, G.;
   Nakatani, Y.; Ishii, T.; Morita, S.; Shibata, K.
2009AGUFMSH33B1498O    Altcode:
  For solar and heliospheric physics, energy release mechanism of
  solar flares and onset of CMEs are one of the most the most important
  issues. Solar Magnetic Activity Research Telescope (SMART) in Hida
  observatory Kyoto University aims to investigate the relation between
  the solar flares and photospheric vector magnetic field. Full disk high
  resolution H-alpha images as well as and photospheric vector magnetic
  field using Fe I 6302 line have been taken regularly since 2005. In
  order to improve the vector magnetic field measurement accuracy,
  a tandem Fabry Perot Stokes polarimeter is newly constructed for
  the SMART. The system consist of a tandem FP with FWHM of ~0.01nm,
  polarization beam splitter and two CCD cameras taking orthogonally
  polarized images simultaneously. In this poster we present the
  system design and laboratory test results, and expected observational
  capabilities. We also present the flux emergence activities observed
  with SMART and Hinode satellite.

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Title: Characteristic Dependence of Umbral Dots on Their Magnetic
    Structure
Authors: Watanabe, H.; Kitai, R.; Ichimoto, K.
2009ApJ...702.1048W    Altcode: 2009arXiv0907.2750W
  Umbral dots (UDs) were observed in a stable sunspot in NOAA 10944 by
  the Hinode Solar Optical Telescope on 2007 March 1. The observation
  program consisted of blue continuum images and spectropolarimetric
  profiles of Fe I 630 nm line. An automatic detection algorithm
  for UDs was applied to the 2 hr continuous blue continuum images,
  and using the obtained data, the lifetime, size, and proper motion
  of UDs were calculated. The magnetic structure of the sunspot was
  derived through the inversion of the spectropolarimetric profiles. We
  calculated the correlations between UD's parameters (size, lifetime,
  occurrence rate, proper motion) and magnetic fields (field strength,
  inclination, azimuth), and obtained the following results. (1) Both
  the lifetime and size of UDs are almost constant regardless of the
  magnetic field strength at their emergence site. (2) The speed of UDs
  increases as the field inclination angle at their emergence site gets
  larger. (3) The direction of movement of UDs is nearly parallel to
  the direction of the horizontal component of magnetic field in the
  region with strongly inclined field, while UDs in the region with
  weakly inclined field show virtually no proper motion. Our results
  describe the basic properties of magnetoconvection in sunspots. We
  will discuss our results in comparison to recent magnetohydrodynamic
  simulations by Schüssler &amp; Vögler and Rempel et al.

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Title: Cooperative observation of solar atmospheric heating by Hida
    observatory and Hinode
Authors: Kitai, R.; Hashimoto, Y.; Anan, T.; Watanabe, H.; Ishii,
   T. T.; Kawate, T.; Matsumoto, T.; Otsuji, K.; Nakamura, T.; Morita,
   S.; Nishizuka, N.; Nishida, K.; Ueno, S.; Nagata, S.; Ichimoto, K.;
   Shibata, K.
2008AGUFMSH41B1625K    Altcode:
  At Hida observatory of Kyoto University, we continue to study solar
  activities and fine structures with Domeless Solar Telescope (DST)
  and Solar Magnetic Activity Research Telescope (SMART). In this work,
  we will report some recent cooperative observational results with
  Hinode on the following topics: (1) Plage heating and waves Analysis
  of a long time series of CaII K spectrograms at a plage area showed
  us a clear co-existence of 3- and 5-min oscillation in Doppler
  velocity. We simulated the response of the VAL model atmosphere to
  the input of 3-min/5-min acoustic disturbances, in 1-D geometry and
  found that plage chromosphere is heated unsteadily by acoustic shock
  waves as was proposed by Carlsson and Stein (1997). (2) Disk spicules
  in and around plage regions We clearly identified numerous ejecting
  features in a plage area. Their morphological shapes of thin tapered
  cylinder and their dynamics strongly suggest that they are spicules
  in plage area. Plage spicules were observed to move under constant
  deceleration, which are driven by acoustic shock waves predicted by
  Shibata and Suematsu (1980) and Hansteen et al. (2007). Our results
  will be discussed from the view point of Type I, II classification
  of limb spicules ( de Pontieu et al. 2007). (3) Umbral dots We have
  confirmed that umbral dots are manifestation of magneto-convection in
  strong magnetic filed from the analysis of Hinode/SOT/BFI&amp;SP. We
  will discuss the plausibility of monolithic umbral model from the
  oscillatory brightening of umbral dots. (4) X-ray brightenings in the
  supergranular network XRT showed us numerous bright points in solar
  quiet regions. Possible relation between these XBPs and supergranular
  network pattern in quiet chromosphere was studied. XBPs were found to be
  located in the network not in the cell center. Many of network bright
  XBPs were consisted of magnetically bipolar loops. (5) Ellerman bombs
  By studying the fine structure of Ellerman bomb, we have found core-halo
  structure and loop like fine-structures in the chromosphere. Discussions
  on the origin of bombs will be given from the viewpoint of magnetic
  reconnection theory.

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Title: Spectropolarimetric Observation of an Emerging Flux Region:
    Triggering Mechanisms of Ellerman Bombs
Authors: Watanabe, H.; Kitai, R.; Okamoto, K.; Nishida, K.; Kiyohara,
   J.; Ueno, S.; Hagino, M.; Ishii, T. T.; Shibata, K.
2008ApJ...684..736W    Altcode: 2008arXiv0805.4266W
  A high spatial resolution observation of an emerging flux region
  (EFR) was made using a vector magnetograph and a Hα Lyot filtergraph
  with the Domeless Solar Telescope at Hida Observatory on 2006 October
  22. In Hα wing images, we could see many Ellerman bombs (EBs) in the
  EFR. Observations in two modes, slit scan and slit fixed, were performed
  with the vector magnetograph, along with the Hα filtergraph. Using the
  Hα wing images, we detected 12 EBs during the slit scan observation
  period and 9 EBs during the slit fixed observation period. With the
  slit scan observation, we found that all the EBs were distributed in
  the area where the spatial gradient of vertical field intensity was
  large, which indicates the possibility of rapid topological change in
  the magnetic field in the area of EBs. With the slit fixed observation,
  we found that EBs were distributed in the areas of undulatory magnetic
  fields, in both the vertical and horizontal components. This paper is
  the first to report the undulatory pattern in the horizontal components
  of the magnetic field, which is also evidence for emerging magnetic flux
  triggered by the Parker instability. These results allow us to confirm
  the association between EBs and emerging flux tubes. Three triggering
  mechanisms for EBs are discussed with respect to emerging flux tubes:
  9 out of 21 EBs occurred at the footpoints of emerging flux tubes,
  8 occurred at the top of emerging flux tubes, and 4 occurred in the
  unipolar region. Each case can be explained by magnetic reconnection
  in the low chromosphere.

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Title: Magnetic Causes of the Eruption of a Quiescent Filament
Authors: Schmieder, B.; Bommier, V.; Kitai, R.; Matsumoto, T.; Ishii,
   T. T.; Hagino, M.; Li, H.; Golub, L.
2008SoPh..247..321S    Altcode: 2007SoPh..tmp..213S
  During the JOP178 campaign in August 2006, we observed the
  disappearance of our target, a large quiescent filament located at
  S25°, after an observation time of three days (24 August to 26
  August). Multi-wavelength instruments were operating: THEMIS/MTR
  ("MulTi-Raies") vector magnetograph, TRACE ("Transition Region and
  Coronal Explorer") at 171 Å and 1600 Å and Hida Domeless Solar
  telescope. Counter-streaming flows (+/−10 km s<SUP>−1</SUP>) in the
  filament were detected more than 24 hours before its eruption. A slow
  rise of the global structure started during this time period with a
  velocity estimated to be of the order of 1 km s<SUP>−1</SUP>. During
  the hour before the eruption (26 August around 09:00 UT) the velocity
  reached 5 km s<SUP>−1</SUP>. The filament eruption is suspected to
  be responsible for a slow CME observed by LASCO around 21:00 UT on 26
  August. No brightening in Hα or in coronal lines, no new emerging
  polarities in the filament channel, even with the high polarimetry
  sensitivity of THEMIS, were detected. We measured a relatively large
  decrease of the photospheric magnetic field strength of the network
  (from 400 G to 100 G), whose downward magnetic tension provides
  stability to the underlying stressed filament magnetic fields. According
  to some MHD models based on turbulent photospheric diffusion, this
  gentle decrease of magnetic strength (the tension) could act as the
  destabilizing mechanism which first leads to the slow filament rise
  and its fast eruption.

---------------------------------------------------------
Title: Magnetic Field Configuration and Evolution of a Highly
    Flare-producitve Region NOAA 10808 (2005-Sep)
Authors: Ishii, T. T.; Nagashima, K.; Kurokawa, H.; Kitai, R.; Ueno,
   S.; Nagata, S.; Shibata, K.
2006IAUJD...3E..59I    Altcode:
  Active regions on the Sun have different flare productivities with each
  other. Some regions produce many large flares, while others produce no
  flares. The key factor of a high flare productivity is the complexity
  of magnetic field configuration of the region. In our previous studies,
  we found that the twisted structure of emerging magnetic flux bundles
  is the essential feature of flare-productive active regions. Vector
  magnetic field data sets are necessary to examine the twisted
  magnetic field structures (e.g., shear and helicity). Recently we
  have constructed our new telescope, Solar Magnetic Activity Research
  Telescope (SMART) at Hida Observatory, Kyoto University. We can obtain
  high resolution full disk H-alpha images (with Lyot filter; H-alpha
  center, blue and reg wing) and full disk vector magnetograms with
  SMART. The active region NOAA 10808 showed the highest flare activity
  during the current solar cycle (cycle 23) in September 2005. We
  studied the formation process of delta-type magnetic configuration
  using SOHO/MDI magnetograms and flares using TRACE data. We also
  studied the evolution of magnetic shear and H-alpha filaments using
  H-alpha full disk images and full disk vector magnetograms obtained
  with SMART. In this paper, we summarize the characteristics of magnetic
  field configuration of this region and discuss the relation between
  the configuration and the high flare activity.

---------------------------------------------------------
Title: SMART Observation of Magnetic Helicity in Solar Filaments
Authors: Hagino, M.; Kitai, R.; Shibata, K.
2006IAUJD...3E..60H    Altcode:
  We examined the magnetic helicity of solar filaments from their
  structure in the chromosphere and corona. The H-alpha telescope of
  the Solar Magnetic Activity Research Telescope (SMART) observed 239
  intermediate filaments from 2005 July 1 to 2006 May 15. The intermediate
  filament usually locates between two active regions. Using these images,
  we identified the filament spine and its barbs, and determined the
  chromospheric filament helicity from the mean angle between each barbs
  and a spine. We found that 71% (78 of 110) of intermediate filaments
  in the northern hemisphere are negative helicity and 67% (87 of 129) of
  filaments in the southern hemisphere are positive, which agreed with the
  well-known hemispheric tendency of the magnetic helicity. Additionally,
  we studied the coronal helicity of intermediate filaments. The coronal
  filament helicity is defined as the crossing angle of threads formed
  a filament. The helicity pattern of coronal filaments obtained with
  EIT/SOHO 171A also shows the helicity hemispheric tendency. Namely, 65%
  (71 of 110) of coronal filaments in the northern hemisphere exhibit
  negative helicity and the 65% (84 of 129) of filaments in the southern
  hemisphere show negative helicity. These data were observed in the
  same day with the SMART H-alpha data. Moreover, we found 12 filament
  eruptions in our data. The 7 of 12 filaments show the clear opposite
  sign of the hemispheric tendency of the magnetic helicity. The helicity
  seems to be change during temporal evolution. This results suggest
  that filament instability may be driven by the opposite sign helicity
  injection from the foot point of the barb.

---------------------------------------------------------
Title: Close causal relation between emergence of twisted flux rope
    and strong flares
Authors: Kurokawa, H.; Ishii, T.; Ueno, S.; Nagata, S.; Kitai, R. .;
   Shibata, K.
2006cosp...36.2230K    Altcode: 2006cosp.meet.2230K
  Solar flares are considered to occur in the solar corona by magnetic
  field reconnection Shibata 1995 The flare energy which is stored in the
  twisted magnetic field is supplied to the corona through the photosphere
  from the convection zone For this reason observations of evolutional
  changes in the magnetic field configuration of flare-productive regions
  are fundamentally important for the flare energy build-up study and
  the forecast of strong flares Hagyard 1984 showed that flares occurred
  along the neutral line of strong magnetic shear The magnetic shear is
  however not a sufficient condition for strong flare occurrence and it
  is important to study the active region evolutions and examine which
  type of magnetic shear development produces strong flares Until now
  several works made detailed studies of magnetic shear developments in
  flare-productive sunspot regions and suggested that the emergence of a
  twisted magnetic flux rope which is originally formed in the convection
  zone must be the source of the strong magnetic shear development in a
  sunspot region to produce a strong flare activity Kurokawa 1987 Tanaka
  1991 Ishii et al 1998 Kurokawa 2002 In this paper we present our recent
  studies of energy build-up processes of flare-productive active regions
  We studied the evolutional changes of 11 super active regions which
  produced more than three X-class flares observed from 1998 through 2005
  during the 23 solar sunspot cycle in details We found all these regions
  show some common magnetic evolutional features in the course of the

---------------------------------------------------------
Title: Transition Region Downflows in the Impulsive Phase of Solar
    Flares
Authors: Kamio, S.; Kurokawa, H.; Brooks, D. H.; Kitai, R.; UeNo, S.
2005ApJ...625.1027K    Altcode:
  We present observations of four flares that occurred during
  coordinated observations between the Coronal Diagnostic Spectrometer
  (CDS) on board SOHO and the Domeless Solar Telescope (DST) at Hida
  Observatory. We studied the evolution of relative Doppler velocities
  in the flare kernels by using He I (3.5×10<SUP>4</SUP> K), O V
  (2.2×10<SUP>5</SUP> K), and Mg IX (1.0×10<SUP>6</SUP> K) spectra
  obtained with high time cadence (42 s) SOHO CDS observations and the
  Hα monochromatic images obtained with the DST. We found that the
  transition region plasma of O V showed strong downward velocities
  up to 87 km s<SUP>-1</SUP> simultaneously with the downflows in the
  lower temperature chromospheric emissions in He I and Hα during the
  impulsive phase of all four flares. From these results we suggest
  that the downflows in the transition region and the chromosphere are a
  common feature in the impulsive phase of flares. For the Mg IX line we
  did not detect any significant change in velocity, which suggests that
  the 10<SUP>6</SUP> K plasma was close to the intermediate temperature
  between the upflowing plasma (10<SUP>7</SUP> K) and the downflowing
  plasma (10<SUP>4</SUP>-10<SUP>5</SUP> K). These are important for
  understanding the dynamics of the solar atmosphere in response to the
  sudden energy deposition of a flare.

---------------------------------------------------------
Title: A Study On Surges: I. Automatic Detection Of Dynamic Hα Dark
    Features From High-Cadence Full-Disk Observations
Authors: Liu, Y.; Kurokawa, H.; Kitai, R.; Ueno, S.; Su, J. T.
2005SoPh..228..149L    Altcode:
  We present a new method for the automatic identification and
  classification of dynamic Hα dark features found in time series of
  full-disk solar images at three Hα wavelengths (center, and ± 0.8
  Å). The simultaneous Hα observations are obtained by the multi-channel
  Flare Monitoring Telescope (FMT) at Hida Observatory. The program
  was developed in order to replace the present visual detection and
  classification of the phenomena. Usually, an obvious dark feature
  found in the Hα −0.8 Å observations probably corresponds to some
  phenomenon such as a surge or chromospheric network enhancement,
  or filament activity. Thus, one of our aims in this program
  is to distinguish each phenomenon by its own properties and key
  parameters. We optimized the threshold values of the key parameters
  such as the area and darkness of the transiently darkening features in
  Hα −0.8 Å so that the computer can reasonably identify surges and
  filament activations. In comparison, for a 7-day observation period,
  the number of dark events detected by the program contains 89% of the
  events recognized visually. However, 10 times more events are detected
  automatically. The missing events are mainly caused by the deletion
  of data with poor visibility. It is found that the dark events can be
  identified with more precise starting and ending times by a machine
  than by a human. Some statistical studies of surges or other activities
  can be carried out based on the computer-produced database. With some
  modifications the program can be applied to monitor real-time dynamic
  features on disk, including flare ribbons.

---------------------------------------------------------
Title: Studies on the Flare Energy Build-Up Process Using SolarB/Solar
    Optical Telescope (SOT) and Solar Magnetic Activity Research Telescope
    (SMART) at Hida Observatory
Authors: Ishii, T. T.; Nagata, S.; Ueno, S.; Kitai, R.; Kurokawa,
   H.; SMART Team
2004ASPC..325..331I    Altcode:
  Evolution of active regions is one of the key topics for understanding
  the energy storage and triggering mechanisms of flares. In our previous
  studies, we found that the twisted structure of emerging magnetic
  flux bundles is the essential feature of flare-productive active
  regions. Vector magnetic field data sets are necessary to examine
  the twisted magnetic field structures (e.g. shear and helicity). The
  SolarB/Solar Optical Telescope (SOT) enables us to study the detailed
  magnetic field configuration with a high spatial resolution. Recently
  we have constructed our new telescope, Solar Magnetic Activity Research
  Telescope (SMART) at Hida Observatory. Vector magnetic field telescope
  of SMART has a much wider field of view (FOV) than that of SOT. In
  this paper, we propose an observational plan of the active region
  evolution and flare energy build-up process with SOT and SMART.

---------------------------------------------------------
Title: The Red-Asymmetry Distribution at Hα  Flare Kernels Observed
    in the 2001 April 10 Solar Flare
Authors: Asai, A.; Ichimoto, K.; Shibata, K.; Kitai, R.; Kurokawa, H.
2004AGUFMSH13A1134A    Altcode:
  We report a detailed examination about the evolution of the Hα flare
  kernels during an X2.3 solar flare which occurred on 2001 April 10. The
  Hα red-asymmetry, that is, the red-shifted Hα emission, is observed
  at almost all Hα flare kernels, during the impulsive phase of the
  flare. At Hα kernels nonthermal particles and/or thermal conduction
  precipitate into the chromospheric plasma, and this is thought to lead
  the downward compression of the chromospheric plasma, which is observed
  as the reddening of Hα emission (e.g. Ichimoto &amp; Kurokawa 1984). We
  examined the evolution of the flare kernels inside the flare ribbons
  by using the Hα images obtained with the Domeless Solar Telescope
  at Hida Observatory, Kyoto University. We also examined the spatial
  distribution of the Hα kernels which show the red-asymmetry and their
  relationship with the intensity of the Hα kernels. We found that the
  stronger the red-asymmetry is, the brighter the Hα kernel is. Then, we
  compared the strengthes of the Hα red-asymmetry at hard X-ray emitting
  sources with those at the Hα kernels without the hard X-ray emissions.

---------------------------------------------------------
Title: Features of Solar Telescopes at the Hida Observatory and the
    Possibilities of Coordinated Observations with SolarB
Authors: Ueno, S.; Nagata, S.; Kitai, R.; Kurokawa, H.
2004ASPC..325..319U    Altcode:
  At the Hida observatory, two solar telescopes, Domeless Solar Telescope
  (DST) and Flare Monitoring Telescope (FMT), have been operated for
  studying solar fundamental structures and active phenomena which affect
  interplanetary environment. In addition, a new telescope named Solar
  Magnetic Activity Research Telescope (SMART) was built from 2002 through
  2003 to obtain simultaneously Hα image and the vector magnetogram
  of the full solar disk with high spatial and temporal resolution. In
  this paper, we give an outline and scientific purposes of these three
  telescopes, with emphasis on the SMART, and discuss about possibilities
  of coordinated observations with SolarB.

---------------------------------------------------------
Title: Short-Duration Active Region Brightenings Observed in the
    Extreme Ultraviolet and Hα by the Solar and Heliospheric Observatory
    Coronal Diagnostic Spectrometer and Hida Domeless Solar Telescope
Authors: Brooks, D. H.; Kurokawa, H.; Kamio, S.; Fludra, A.; Ishii,
   T. T.; Kitai, R.; Kozu, H.; Ueno, S.; Yoshimura, K.
2004ApJ...602.1051B    Altcode:
  We present the first detection of an Hα counterpart to the EUV
  blinker. The observations come from a coordinated campaign between
  the Hida Observatory Domeless Solar Telescope (DST) and the Solar
  and Heliospheric Observatory Coronal Diagnostic Spectrometer (CDS)
  conducted in 2002 July and August. Utilizing studies designed for
  high-cadence observations, many short-duration brightenings (&lt;3
  minutes) were identified in the He I λ584.334 and O V λ629.732
  spectral lines in CDS data of active region NOAA 10039/10044. These
  brightenings show similar characteristics (increases in intensity,
  size) to longer duration EUV blinkers previously reported in active
  regions and the quiet Sun. Focusing on two events that show pronounced
  emission in the upper chromosphere (He I), we have been able to identify
  cospatial bright points in the lower chromosphere (Hα center, +/-0.5
  Å) that show enhanced emission during the EUV blinker. These bright
  features have lifetimes similar to those of their EUV counterparts,
  and their peak intensities occur nearly simultaneously with the peak
  blinker intensities in the He I and O V lines. In both cases the He
  I and O V lines show excess line broadening at the peak of the event
  (&gt;15 km s<SUP>-1</SUP>). Our high-cadence observations also enabled
  us to examine the dimensions and lifetimes of short-duration active
  region blinkers in detail. We find that the instrumental spatial and
  temporal resolution can combine to distort their characteristics:
  even short-duration blinkers appear to be composed of elementary
  brightening events. The optical brightenings also appear to closely
  follow the behavior of the elementary brightenings. The spatial and
  temporal relationships between the brightenings indicate a causal link
  between the EUV and Hα blinkers.

---------------------------------------------------------
Title: Short Duration Active Region Brightenings Observed in the
    EUV and Ha by SOHO/CDS and HIDA/DST
Authors: Brooks, D. H.; Kurokawa, H.; Kamio, S.; Fludra, A.; Ishii,
   T. T.; Kitai, R.; Kosu, H.; Ueno, S.; Yoshimura, K.
2004ESASP.547..273B    Altcode: 2004soho...13..273B
  We present the 1st detection of an H counterpart to the EUV blinker,
  using observations from a coordinated campaign between the SOHO Coronal
  Diagnostic Spectrometer and the Kyoto University Hida Observatory,
  Domeless Solar Telescope (DST). The observations were performed during
  July and August 2002. By designing the CDS observing sequences for
  high cadence and long duration observations, we were able to identify
  many short duration (&lt;3 mins.) brightenings simultaneously in the
  He I 584.334A and O V 629.732A spectral lines. These brightenings
  show similar characteristics (intensity increases, sizes) to longer
  duration EUV blinkers previously reported in active regions and the
  'quiet' Sun. Focusing on two events which show pronounced emission
  in the upper chromosphere (He I), we have been able to identify
  cospatial bright points in the lower chromosphere (H line centre,
  60.5A) which show enhanced emission during the EUV blinkers. These
  bright features have similar lifetimes to their EUV counterparts and
  their peak intensities occur close to simultaneously with the peak
  blinker intensities in the He I and O V lines. In both cases the He
  I and O V lines show excess line broadening at the peak of the event
  (&gt;15 km s01) and in one event evidence of downward (red-shifted)
  motion is observed. A statistical study is being performed to provide
  a complete picture of the line width and velocity characteristics of
  these events and to determine whether the H counterparts are common, or
  confined to specific blinkers with pronounced He I emission. The high
  cadence of our observations also allowed us to examine the eects of
  spatial and temporal averaging on the determination of the properties
  of blinkers. We find that both short and long duration blinkers are
  composed of elementary brightening events and that such events can
  be undetectable in observations with low temporal cadence. Finally,
  the H brightenings appear to correlate well with the elementary EUV
  brightening events.

---------------------------------------------------------
Title: Evidence for a Flux Rope driven EUV wave and CME: Comparison
    with the Piston Shock Model
Authors: Foley, C. R.; Harra, L. K.; Matthews, S. A.; Culhane, J. L.;
   Kitai, R.
2003A&A...399..749F    Altcode:
  This paper examines the relationship between a coronal wave, filament
  eruption, flare and Coronal Mass Ejection (CME) which occurred on
  2001, April 10th. We study the pre-flare activity which includes the
  eruption of a filament and a coronal wave. A large X-ray flare and
  a CME follow. We discuss how these phenomena are related and compare
  our results to recent models. These are found to be largely consistent
  with the numerical simulations of a flux rope driven CME as presented
  recently in Chen et al. (2002).

---------------------------------------------------------
Title: Simultaneous Observation of a Moreton Wave on 1997 November
    3 in Hα and Soft X-Rays
Authors: Narukage, N.; Hudson, H. S.; Morimoto, T.; Akiyama, S.;
   Kitai, R.; Kurokawa, H.; Shibata, K.
2002ApJ...572L.109N    Altcode:
  We report the observation of a Moreton wave in Hα (line center and
  +/-0.8 Å) with the Flare Monitoring Telescope at the Hida Observatory
  of Kyoto University at 4:36-4:41 UT on 1997 November 3. The same
  region (NOAA Active Region 8100) was simultaneously observed in soft
  X-rays with the soft X-ray telescope on board Yohkoh, and a wavelike
  disturbance (“X-ray wave”) was also found. The position of the wave
  front as well as the direction of propagation of the X-ray wave roughly
  agree with those of the Moreton wave. The propagation speeds of the
  Moreton wave and the X-ray wave are about 490+/-40 and 630+/-100 km
  s<SUP>-1</SUP>, respectively. Assuming that the X-ray wave is an MHD
  fast-mode shock, we can estimate the propagation speed of the shock, on
  the basis of MHD shock theory and the observed soft X-ray intensities
  ahead of and behind the X-ray wave front. The estimated fast shock
  speed is 400-760 km s<SUP>-1</SUP>, which is in rough agreement with
  the observed propagation speed of the X-ray wave. The fast-mode Mach
  number of the X-ray wave is also estimated to be about 1.15-1.25. These
  results suggest that the X-ray wave is a weak MHD fast-mode shock
  propagating through the corona and hence is the coronal counterpart
  of the Moreton wave.

---------------------------------------------------------
Title: Multi-wavelength Observations of a Moreton Wave on 2000 March 3
Authors: Narukage, N.; Morimoto, T.; Kitai, R.; Kurokawa, H.;
   Shibata, K.
2002aprm.conf..449N    Altcode:
  Moreton waves are flare-associated waves observed to propagate across
  the solar disk in Hα (Moreton, 1960). Such waves have been identified
  as the intersections of a coronal fast-mode shock fronts and the
  chromosphere (Uchida, 1968). We report the observation of a Moreton
  wave in Hα (line center and ± 0.8 Å) with the Flare Monitoring
  Telescope (FMT) at the Hida Observatory of Kyoto University on 2000
  March 3. The same region (NOAA 8882) was simultaneously observed in
  soft X-rays with the soft X-ray Telescope (SXT) on board Yohkoh, and
  a coronal wave-like disturbance (“X-ray wave") was also found. The
  region (NOAA 8882) is near the solar limb. Hence the chromospheric
  Moreton wave propagated on the solar disk at a speed of 1050 km/s,
  whereas the coronal X-ray wave propagated towards the outer corona
  at 1300 km/s. We identified the X-ray wave as an MHD fast-mode shock,
  i.e. a coronal counterpart of the Moreton wave, using MHD shock theory
  and the observed soft X-ray intensities (Narukage et al., 2002). On the
  basis of this result, the propagation of these two waves indicates the
  3-dimensional structure of the flare-associated shock wave. This event
  is the first observation of the 3-d structure of the shock. Moreover, a
  type II radio burst and a coronal mass ejection (CME) were also observed
  simultaneously. The shock speed given by the type II radio burst is 1150
  km/s. The CME propagated at a speed of 800 km/s. A basic component of
  CME is a density enhancement, and the shock preceding the CME propagates
  roughly 1.5 times faster than the CME, in this case at 1200 km/s.

---------------------------------------------------------
Title: Convective Structure in an Emerging Flux Region
Authors: Kozu, H.; Kitai, R.
2002mwoc.conf...83K    Altcode:
  The magnetic field in the Sun is created near the bottom of convective
  layer and some of them emerges through convective zone as emerging flux
  loops. Flares, surges and other active phenomena can be triggered by
  the emerging flux which is affected by surrounding convective motion
  and convective structure can play an important role in basic mechanism
  of such active events. We observed emerging flux region NOAA 8582 in the
  G-band wavelength from 21:00UT to 23:30UT on 1999 June 11 with Real-time
  Frame Selector2 (RTFS2) installed in Domeless Solar Telescope in Hida
  Observatory, Kyoto University. We observed simultaneously H alpha
  center and its wing wavelength with Lyot filter system. We can see many
  emerging flux loops and surge activities during the observation period
  in H alpha data set. We applied Local Correlation Tracking Method (LCTM)
  to the G-band data set and derived horizontal convective structure in
  the upper convective zone from it. The resulting convective structure
  changed temporary and it can be interpreted as meso-scale convective
  structure. In addition to the varying convective structure we found a
  temporary continuous up-flow structure under emerging flux loops. The
  structure existed continually during the whole observation period and
  fixed to the position of middle of foot points of each flux loops. It
  means that the up-flow structure is characteristic of the emerging
  flux region.

---------------------------------------------------------
Title: Multi-Wavelength Observation of A Moreton Wave on November
    3, 1997
Authors: Narukage, N.; Shibata, K.; Hudson, H. S.; Eto, S.; Isobe,
   H.; Asai, A.; Morimoto, T.; Kozu, H.; Ishii, T. T.; Akiyama, S.;
   Kitai, R.; Kurokawa, H.
2002mwoc.conf..295N    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Fine Structure inside Flare Ribbons and Temporal Evolution
Authors: Asai, A.; Masuda, S.; Yokoyama, T.; Shimojo, M.; Kurokawa,
   H.; Shibata, K.; Ishii, T. T.; Kitai, R.; Isobe, H.; Yaji, K.
2002mwoc.conf..221A    Altcode:
  Non-thermal particles generated in the impulsive phase of
  solar flares are observed mainly in microwave, hard X-rays, and
  gamma-rays. Observations in Hα can also give important informations
  about non-thermal particles precipitating into the chromosphere with
  a higher spatial resolution than in other wavelengths. We observed an
  X2.3 flare which occurred in the active region NOAA 9415 on 10 April
  2001, in Hα with Sartorius Telescope at Kwasan Observatory, Kyoto
  University. Thanks to the short exposure time given for the flare, the
  Hα images show fine structures inside the flare ribbons. In addition
  to Hα, we analyze microwave, hard X-ray, and EUV data obtained with
  Nobeyama Radioheliograph, Yohkoh/HXT, and TRACE, respectively. In Hα,
  several bright kernels are observed in the flare ribbons. On the other
  hand, the hard X-ray images show only a single pair of bright sources
  which correspond to one of several pairs of Hα kernels. Examining
  the difference in the magnetic field strength and in the time profiles
  of Hα emission for these kernels, we discuss the reason why only one
  pair kernels are bright in the hard X-ray among the other bright Hα
  kernels. Comparing the Hα images with EUV images, we also examine
  the three-dimensional structure of solar flares. While broad and
  network-like ribbons are observed in Hα, the width of EUV ribbons is
  relatively narrow, and EUV ribbons are located at the outer edges of
  the corresponding Hα ribbon.

---------------------------------------------------------
Title: Simultaneous observations of Moreton waves in Hα and Soft
    X-ray
Authors: Narukage, N.; Hudson, H.; Morimoto, T.; Kitai, R.; Kurokawa,
   H.; Shibata, K.
2002cosp...34E1337N    Altcode: 2002cosp.meetE1337N
  Moreton waves are flare-associated waves observed to propagate
  across the solar disk in H (Moreton, 1960). Such waves have been
  identified as the intersections of a coronal fast-mode shock fronts
  and the chromosphere (Uchida, 1967). We report the two observations of
  Moreton waves in H (line center and +/- 0.8 A) with the Flare Monitoring
  Telescope (FMT) at the Hida Observatory of Kyoto University. The both
  events were simultaneously observed in soft X-rays with the Soft X-ray
  Telescope (SXT) on board Yohkoh, and wave-like disturbances ("X-ray
  wave") were also found. One event occurred in solar-disk on November 3,
  1997, the other near solar limb on March 3, 2000. Assuming that the
  X-ray waves are the MHD fast shocks, we can estimate the propagation
  speeds of the shocks, based on the MHD shock theory and the observed
  soft X-ray intensities ahead and behind the X-ray wave fronts. It is
  found that the estimated fast shock speeds are in rough agreement with
  the observed propagation speeds of the X-ray waves. The fast mode Mach
  numbers of the X-ray waves are also estimated. These results suggest
  that the X-ray waves are MHD fast shocks propagating through the corona
  and hence are the coronal counterparts of the Moreton waves.

---------------------------------------------------------
Title: Observations of Moreton Waves and EIT Waves
Authors: Shibata, K.; Eto, S.; Narukage, N.; Isobe, H.; Morimoto,
   T.; Kozu, H.; Asai, A.; Ishii, T.; Akiyama, S.; Ueno, S.; Kitai, R.;
   Kurokawa, H.; Yashiro, S.; Thompson, B. J.; Wang, T.; Hudson, H. S.
2002mwoc.conf..279S    Altcode:
  The Moreton wave is a flare-associated wave observed in H alpha, and
  is now established to be a fast mode MHD shock emitted from the flare,
  but the physical mechanism to create the wave is still puzzling. On
  the other hand, the EIT wave is a newly discovered flare-associated
  wave observed in EUV with the Extreme ultraviolet Imaging Telescope
  (EIT) aboard SOHO, and in this case, not only its origin but also
  its physical property are both puzzling. We study the relationship
  of these two flare-associated waves, Moreton waves and EIT waves, by
  analyzing 4 events observed on Nov. 3 and 4, 1997, Aug. 8, 1998, and
  Mar. 3, 2000 (Narukage et al. 2001). The Moreton waves were observed
  in Ha, Ha+0.8A and Ha-0.8A with the Flare Monitoring Telescope (FMT)
  at the Hida Observatory of Kyoto University, while the EIT waves were
  observed with SOHO/EIT. In the typical case associated with an X-class
  flare in AR 8100 on 4 November 1997 (Eto et al. 2001) the propagation
  speeds of the Moreton wave and the EIT wave were approximately 780
  km/s and 200 km/s respectively. The data on speed and location show
  clearly that the Moreton wave differs physically from the EIT wave in
  this case. The detailed analyses of the other events (Nov. 3, 1997,
  Aug. 8, 1998, and Mar. 3, 2000) will also be presented, with Yohkoh/SXT
  data in the lucky case.

---------------------------------------------------------
Title: Distribution of the Green- and Red-Line Coronal Emissions
    and Their Contribution to the K-Corona
Authors: Takeda, A.; Kurokawa, H.; Kitai, R.; Ishiura, K.
2001AGUSM..SH41B06T    Altcode:
  We have made a detailed analysis of the high-resolution images of
  the corona obtained during the total solar eclipse on 1991, July
  11. The purpose of the analysis is to derive the temperature and
  density structure of the observed corona as reliable as possible
  by using the absolute intensities of the the green (530.3 nm) and
  red (637.4 nm) coronal emission lines and then contrasted to the
  continuum intensity. First, we focus our attention to the loops
  appeared distinctly in emission-line images. With the help of a
  structure-enhancement algorithm, we show the following results in a
  quantitative way. (1) The green- and red-line loops are quite separately
  distributed in space. (2) In the innermost corona, structures in the
  red-line tend to contribute more to the total column density than
  the green-line structures. Second, we study individual emission-line
  loops and find that, (1) The electron densities are almost the same
  between the two wavelengths. (2) Density-falls with height are nearly
  hydrostatic in most loops, while some red-line loops significantly
  deflected from the hydrostatic curve. (3) Column density of the analysed
  loops only explains 0.1 to 0.2 of the total column density derived from
  the continuum intensity at the same point. Then, we propose a method to
  determine the contribution of the non-loop component of these emission
  lines to the total column density. It is found that the total column
  density in the analyzed region can be reasonably explained by a mixture
  of the 530.3 nm component with a line-of-sight length comparable to the
  size of the active region, and the 637.4 nm component, which tends to
  concentrate in loop structures. We thereby conclude that the observed
  corona is well explained by plasma of temperatures ranging from 1 MK
  to 2 MK.

---------------------------------------------------------
Title: Preliminary study of the evolution of solar magnetic structures
    and photospheric horizontal velocity fields
Authors: UeNo, S.; Kitai, R.; Ichimoto, K.; Sakurai, T.; Soltau, D.;
   Brandt, P. N.
2001AdSpR..26.1793U    Altcode:
  In October 1997, we made a coordinated observation of the solar
  photosphere and chromosphere at Hida observatory (Kyoto university,
  Japan) and at Teide observatory (Tenerife) over a 10 day. We obtained
  imaging data series continuously during 6 hr 45 min in G-band (4308 Å)
  observed with the Domeless Solar Telescope (DST) at Hida on 24th October
  (effective FOV; 96″×99″). Additionally, in this observation,
  we simultaneously observed image series of the chromosphere during
  the latter 4 hr 10 min in H α line center and H α ±0.6 Å. From
  these data set, we could detect that emerging flux tubes crossed
  the photosphere to the chromosphere and that 'convective collapse'
  phenomena appeared at the stage of the spot formation. Moreover,
  we confirmed that the lifetime of mesogranulation was about 4000 sec
  (70 min) from the temporal evolution of velocity patterns. We show
  here only a summary of these observations.

---------------------------------------------------------
Title: Density Structure of the Coronal Loops Derived from the 1991
    Total Eclipse Observation
Authors: Takeda, A.; Kurokawa, H.; Kitai, R.; Ishiura, K.
2000ASPC..205..113T    Altcode: 2000ltse.conf..113T
  High-resolution images of the corona obtained during the total solar
  eclipse on 11th July, 1991 were carefully analyzed to derive the
  electron densities along the loops of the green(530.3 nm) and red(637.4
  nm) emission lines. We found no difference more than a factor of 2
  between the averaged densities of the green and the red line loops
  at corresponding heights. Most of the analyzed loops were found to be
  approximately in hydrostatic equilibrium.

---------------------------------------------------------
Title: An observational search for giant cells in the sun
Authors: Kitai, R.; Kurokawa, H.; Funakoshi, Y.; Ishiura, K.; Kimura,
   G.; Shinkawa, T.
1999AdSpR..24..237K    Altcode:
  With the supergranular network pattern seen in Hα wing image of the
  Sun as tracers, we derived large-scale horizontal flow field over the
  solar surface by a local-correlation-tracking method. We have found
  some evidences of the existence of large scale flow cells on the Sun.

---------------------------------------------------------
Title: Observational relationship between meso-sized convection and
    5-min oscillation in the solar atmosphere
Authors: Ueno, S.; Kitai, R.
1998IAUS..185..457U    Altcode:
  In order to understand 3-dimensional structures of upper
  solar convection zone, we performed two different kinds of
  observation simultaneously with the Domeless Solar Telescope of
  Hida Observatory. One is the 2D imaging observation of solar quiet
  photosphere in wavelengths around lambda4308 AA. Another is the slit
  1D spectroscopy of the neutral iron line lambda6302.5 AA; at the
  central region of the field-of-view of the imaging observation. Thus
  the horizontal velocity field is obtained from the former observation,
  while the radial velocity field is obtained from the latter one at
  the same region. In both velocity fields, we found the meso-sized
  structures and confirmed convective nature of the flow. And we observed
  that amplitudes of 5-min oscillations were increased soon after large
  downward motions of convection, similar to the other observations'
  results (T.R. Rimmele, P.R. Goode, E. Harold, and R.T. Stebbins 1995;
  O. Espagnet, R. Muller, Th. Roudier, P. Mein, N. Mein, and J.M. Malherbe
  1996). Moreover, we report the possible relationship between horizontal
  velocity gradient distributions and oscillation excitations.

---------------------------------------------------------
Title: Horizontal Flow Field in the Solar Photosphere
Authors: Kitai, R.; Funakoshi, Y.; Ueno, S.; Sano, S.; Ichimoto, K.
1998ASSL..229..319K    Altcode: 1998opaf.conf..319K
  No abstract at ADS

---------------------------------------------------------
Title: Post-Flare Loops of 26 June 1992 - IV. Formation and Expansion
    of Hot and Cool Loops
Authors: Van Driel-Gesztelyi, L.; Wiik, J. E.; Schmieder, B.; Tarbell,
   T.; Kitai, R.; Funakoshi, Y.; Anwar, B.
1997SoPh..174..151V    Altcode:
  Observations of the post-flare loops after the X3.9 flare which occurred
  on 25 June, 1992 at 20:11 UT by the Yohkoh/SXT in X-rays, as well as
  in Hα obtained at 5 different observatories, have provided a unique,
  longest ever, set of data for a study of the relationship between the
  hot and cool post-flare loops as they evolve. At any given time, the
  altitude difference between the hot X-ray loops of 6-7× 10<SUP>6</SUP>
  K and the cool Hα loops of 1.5× 10<SUP>4</SUP> K is related to the
  expansion rate of the loop systems and their cooling time. Therefore,
  measurements of the expansion rate and relative height of hot and
  cool loops can provide direct observational values for their cooling
  times. We measured the altitude of hot and cool loops for 15 and 19
  hours, respectively, and found that the cooling time increased as the
  density of the loops decreased. We found a reasonably good agreement
  between the observed cooling times and those obtained from model
  calculations, although the observed values were always somewhat longer
  than the theoretical ones. Taking into account evolutionary effects,
  we also found similar shapes and configurations of hot and cool loops
  during the entire observing period and confirmed that, at any time,
  hot loops are at higher altitude than cool loops, suggesting that cool
  loops indeed evolve from hot loops. These results were used to check
  the validity of the reconnection model.

---------------------------------------------------------
Title: Global and Fine Scale Distribution of the Innermost Coronal
    Temperature
Authors: Takeda, A.; Kurokawa, H.; Kitai, R.; Ishiura, K.
1997IAUJD..19E..50T    Altcode:
  The observations of the solar corona at the total eclipses continue to
  provide us with valuable data, which enables us to study the thermo
  dynamic structures. Because of the extremely low scattered lights,
  coronal emission intensities measured during the eclipse time are still
  higher in accuracy and resolution than the observation from space. It
  is rare chance to study temperature and density structure of the very
  innermost part of the corona at visible wavelengths. In this paper,
  we present the spatial variations of the absolute intensities of the
  active region corona from 1.05 to 1.5 R<SUB>odot</SUB> observed at the
  total eclipse of 11th July, 1991, in three wavelengths of 2 coronal
  emission lines (Fe XIV 530.3 nm and Fe X 637.4 nm) and the continuum
  around 610.0nm. Global temperature estimation by taking the intensity
  ratio, Fe XIV/Fe X, indicates that average temperature is not always the
  highest in the prominent active region corona, since there exists large
  amount of the cooler plasma together with the hotter component. Next,
  we examine spatial correlation among the fine structures at above
  three wavelengths, and show semi-quantitatively that most 1.0 times
  10^6K (Fe X) and 2.0 times 10^6K (Fe XIV) plasma are isolated with
  each other, and that, if they combined, they explain about 70% of the
  continuum structures.

---------------------------------------------------------
Title: Relative Altitude of Hot and Cool Post-Flare Loops
Authors: van Driel-Gesztelyi, L.; Schmieder, B.; Wiik, J. E.; Tarbell,
   T.; Heinzel, P.; Kitai, R.; Funakoshi, Y.; Anwar, B.
1996ASPC..111..359V    Altcode: 1997ASPC..111..359V
  The authors collected a unique set of data obtained simultaneously at
  4 different ground based observatories and with the Yohkoh satellite
  to study the relationship between hot X-ray and cool Hα post-flare
  loops as they evolved during the long gradual phase of the X3.9 flare
  which occurred on 25 June 1992. They found reasonably good agreement
  between the computed 'theoretical' cooling times and the 'observed'
  cooling times derived from the relative altitudes of hot and cool
  loops. Taking into account evolutionary effects, the authors also found
  similar shape and configuration of hot and cool loops during the entire
  observing period and confirmed that at any time hot loops are at higher
  altitude than cool loops, suggesting that cool loops indeed descend
  from hot loops. The results provide support for the reconnection model.

---------------------------------------------------------
Title: He I 10830 Angstroms in Solar Active Regions and its
    Correlation with Chromospheric Lines
Authors: Kitai, R.; Tohmura, I.; Suematsu, Y.; Akioka, M.; Soltau, D.
1996mpsa.conf..435K    Altcode: 1996IAUCo.153..435K
  No abstract at ADS

---------------------------------------------------------
Title: Comparison of High Resolution Optical and Soft X-ray Images
    of Solar Corona
Authors: Takeda, A.; Kurokawa, H.; Kitai, R.; Ishiura, K.; Golub, L.
1996mpsa.conf..483T    Altcode: 1996IAUCo.153..483T
  No abstract at ADS

---------------------------------------------------------
Title: Electron Acceleration Site of the 1992 Sep. 6 Flare
Authors: Fujiki, K.; Nakajima, H.; Hanaoka, Y.; Yaji, K.; Kitai, R.
1996mpsa.conf..547F    Altcode: 1996IAUCo.153..547F
  No abstract at ADS

---------------------------------------------------------
Title: Peculiar magnetic field evolution of active region NOAA 7562
    in August 1993 - results from campaign observation with Yohkoh
Authors: Sakurai, T.; Suematsu, Y.; Ichimoto, K.; Kurokawa, H.; Kitai,
   R.; Akioka, M.; Tohmura, I.; Soltau, D.; Mickey, D. L.; Zhang, H.;
   Li, W.; Zirin, H.; Tang, F.
1994ESASP.373..337S    Altcode: 1994soho....3..337S
  No abstract at ADS

---------------------------------------------------------
Title: A Morphological Study of Magnetic Shear Development in a
    Flare-Productive Region NOAA 7270
Authors: Kurokawa, H.; Kitai, R.; Kawai, G.; Shibata, K.; Yaji, K.;
   Ichimoto, K.; Nitta, N.; Zhang, H.
1994kofu.symp..283K    Altcode:
  The evolutional changes of a flare-productive region NOAA 7270 were
  examined in details with high resolution H_alpha images, magnetograms
  and soft X-ray images to study the process of the magnetic shear
  development and its relation to the strong flare activity of the
  region. This study led us to the following results and a conclusion:(1)
  Several new bipolar pairs simultaneously and or successively emerged in
  NOAA 7270 from 5 through 7 September. (2) Magnetic shear configurations
  developed at three locations, where most of flares occurred from 5
  through 7 , September. (3)These magnetic shear configurations were
  formed by successive emergences of twisted magnetic ropes from below
  the photosphere.

---------------------------------------------------------
Title: Thermal and Density Structure of the Inner Corona Observed
    at the 1991 Total Solar Eclipse
Authors: Takeda, A.; Kurokawa, H.; Kitai, R.; Ishiura, K.
1994kofu.symp..381T    Altcode:
  We observed the total solar eclipse on 11 July, 1991 with the
  multi-channel telescope at Lapaz,Mexico, and successfully obtained
  high-resolution pictures of the innermost corona at the wavelength
  shown in Table 1. This is a brief summary of preliminary results
  obtained from the photometric mesurement of the photographic pictures
  and their image processing.

---------------------------------------------------------
Title: Flares on September 6, 1992
Authors: Kitai, R.; Kurokawa, H.; Funakoshi, Y.; Nakai, Y.; Shibata,
   K.; Yaji, K.; Nitta, N.; YOHKOH Team; NAOJ Flare Telescope Team
1994kofu.symp..147K    Altcode:
  We present some preliminary results of our observational
  study of typical eruptive flares in NOAA7270 on September 6,
  1992. (1)Magnetic shear and flux emergence are strongly related to
  flare production. (2)Observed flares showed a common temporal relation
  between cool plasma dynamics seen in H_alpha and coronal energy releases
  seen in YOHKOH data. (3)At the pre-heating stage of flares, there were
  some indications of slow reconnection of adjacent magnetic loops.

---------------------------------------------------------
Title: Fine Structures of the Inner Corona Observed at the 1991
    Total Solar Eclipse
Authors: Takeda, A.; Kurokawa, H.; Kitai, R.; Ishiura, K.
1994scs..conf..565T    Altcode: 1994IAUCo.144..565T
  No abstract at ADS

---------------------------------------------------------
Title: A Prominenece Eruption Followed by a Coronal Arcade Formation
    on July 30-31, 1992
Authors: Hanaoka, Y.; Kurokawa, H.; Enome, S.; Nakajima, H.; Shibasaki,
   K.; Nishio, M.; Takano, T.; Torii, C.; Sekiguchi, H.; Kawashima, S.;
   Bushimata, T.; Shinohara, N.; Irimajiri, Y.; Koshiishi, H.; Shiomi,
   Y.; Nakai, Y.; Funakoshi, Y.; Kitai, R.; Ishiura, K.; Kimura, G.
1994xspy.conf..193H    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Prominence Eruption in NOAA7125 on April 6, 1992
Authors: Kitai, R.; Kawai, G.; Anwar, B.; Kurokawa, H.; Funakoshi,
   Y.; Nakai, Y.; Tsuneta, S.
1994xspy.conf..287K    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Flares on 1992 September 6
Authors: Shibata, K.; Nitta, N.; Kitai, R.; Kurokawa, H.; Yaji, K.;
   Kato, T.; Zarro, D. M.
1993BAAS...25R1187S    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: High resolution observations of active phenomena obtained at
    Hida Observatory
Authors: Kurokawa, H.; Nakai, Y.; Funakoshi, Y.; Kitai, R.
1991AdSpR..11e.233K    Altcode: 1991AdSpR..11..233K
  Samples of high-resolution observations of solar active regions and
  flares obtained with the 60-cm Domeless Solar Telescope (DST) at
  Hida Observatory, Kyoto University are presented. What gives rise to
  the twist and shear in the magnetic loop structures is the essential
  question for the study of solar active phenomena. Several examples
  showing the development of twisted or sheared magnetic structures
  are demonstrated and morphologically studied. Two examples of
  high-resolution spectra of a flare and spicules are also demonstrated.

---------------------------------------------------------
Title: Photospheric and Chromospheric Umbral Dots in a Decaying
    Sunspot
Authors: Kitai, R.
1986SoPh..104..287K    Altcode:
  Time-sequenced Hα filtergrams and narrow-band blue filtergrams
  (λ<SUB>0</SUB> = 4308 Å, Δλ = 10 Å) of umbral dots in a decaying
  sunspot were studied. The results are: (a) Photospheric umbral dots
  have lifetimes of about 40 min. (b) Two types of proper motion were
  found for photospheric umbral dots. Umbral dots born in the umbra or
  in the light bridge show virtually no proper motion. On the other hand,
  umbral dots of penumbral origin move inward to the umbra with speeds of
  about 0.4 km s <SUP>−1</SUP>. (c) Chromospheric umbral dots, which
  have dimensions of 0″.6 × 1″.2 in the mean, were more numerously
  found than photospheric umbral dots. (d) Photospheric umbral dots were
  observed to be associated with chromospheric umbral dots. Thus umbral
  dots are not phenomena confined to photospheric levels but also extend
  to chromospheric levels. (e) Some of the chromospheric umbral dots are
  unrelated to the photospheric umbral dots. They may be excited by the
  infalling matter from the umbral corona.

---------------------------------------------------------
Title: The Kwasan Image Processing System.
Authors: Nakai, Y.; Kitai, R.; Asada, T.; Iwasaki, K.
1986MmKyo..37...59N    Altcode:
  The Kwasan Image Processing System is a general purpose interactive
  image processing and analyzing system designed to process a large
  amount of photographic and photoelectric data. The hardware of
  the system mainly consists of a PDS MICRO-10 microdensitometer,
  a VAX-11/750 minicomputer, a 456 M bytes Winchester disk and a VS11
  color-graphic terminal. The application programs "PDS, KIPS, STII"
  enable users to analyze spectrographic plates and two-dimensional
  images without site-special knowledge of programming.

---------------------------------------------------------
Title: On the Relation Between Chromospheric and Photospheric Fine
    Structure in an Active Region
Authors: Kitai, R.; Muller, R.
1984SoPh...90..303K    Altcode:
  A comparative study was done on the bright fine structure in the upper
  photosphere and in the lower chromosphere of an active region. The
  results are shown in the following: (a) The bright points in the Hα
  wing are cospatial to the facular points, which confirms the result of
  Wilson (1981). (b) Some points bright in the Hα wing are associated
  with the facular granules which have larger sizes than the facular
  points, (c) The brightness enhancement in the Ha wing is positively
  correlated to the enhancement in the blue continuum. However, the
  correlation is not so strong. (d) The moustache points are also
  cospatial to the facular features. (e) The geometrical shape of a
  moustache point is like a funnel and diverging upward in the upper
  photospheric and the lower chromospheric levels.

---------------------------------------------------------
Title: On the mass motions and the atmospheric states of moustaches.
Authors: Kitai, R.
1983SoPh...87..135K    Altcode:
  Analyses of broad moustache profiles of Balmer lines and Ca II H and K
  lines are performed based upon our spectroscopic observation under good
  seeing conditions. Hα emission profiles are found to consist of three
  components, i.e., a central absorption, a Gaussian core and a power-law
  wing. Each of them has a different Doppler shift from others. From
  the data of Doppler shifts, mass motions with velocity of about 6 km
  s<SUP>−1</SUP> are found to be present in chromospheric levels of
  moustache atmospheres. Computations of Hα emission profiles radiated
  from a variety of model atmospheres are made. Comparison of computed
  profiles with the observed ones leads us to the conclusion that a broad
  Hα profile is due to a formation of heated (ΔT = 1500 K) and condensed
  (ϱ/ϱ<SUB>0</SUB> = 5) chromospheric layers relative to the normal.

---------------------------------------------------------
Title: Numerical Hydrodynamics of the Jet Phenomena in the Solar
    Atmosphere - Part Two - Surges
Authors: Shibata, K.; Nishikawa, T.; Kitai, R.; Suematsu, Y.
1982SoPh...77..121S    Altcode:
  One-dimensional hydrodynamic simulations of surges are performed in
  order to make clear their origin and structure. Surges are regarded as
  the jets resulting from a sudden pressure increase at the base of the
  model atmosphere. The height of the explosion (h<SUB>0</SUB>), which
  is measured from the level of τ<SUB>5000</SUB> = 1, is regarded as a
  free parameter. Another free parameter is the strength of the sudden
  pressure increase (p/p<SUB>0</SUB>) at h<SUB>0</SUB>. Simulations
  are performed for values in the ranges of 540 km ≤ h<SUB>0</SUB>
  ≤ 1920 km and 3 ≤ p/p<SUB>0</SUB> ≤ 30. It was found that for a
  fixed p/p<SUB>0</SUB> there exists a critical height (h<SUB>c</SUB>)
  in h<SUB>0</SUB>, which separates the jet (surge) models into two
  types. For h<SUB>0</SUB> &gt; h<SUB>c</SUB>, jets are produced directly
  by the pressure gradient force near h<SUB>0</SUB>, and made of the
  matter ejected from the explosion itself. The essential hydrodynamic
  structure of this type is the same as that in a shock tube (this type
  is called `shock tube' type). For h<SUB>0</SUB> &lt; h<SUB>c</SUB>,
  jets are not the direct results of the pressure enhancement, but
  are produced by the shock wave which are generated by the pressure
  enhancement and which has propagated through the chromosphere (this type
  is called the `crest shock' type). It is shown that the critical height
  (h<SUB>c</SUB>) ranges from 1000 km to 1500 km for 3 ≤ p/p<SUB>0</SUB>
  ≤ 30. General properties of both types are investigated in detail. The
  results are compared with observations and it is concluded that small
  surges associated with Ellerman bombsbelong to the `crest shock' type,
  i.e. they are produced by the shock wave.

---------------------------------------------------------
Title: Numerical Hydrodynamics of the Jet Phenomena in the Solar
    Atmosphere - Part One - Spicules
Authors: Suematsu, Y.; Shibata, K.; Neshikawa, T.; Kitai, R.
1982SoPh...75...99S    Altcode:
  We present a spicule model whose eruption occurs as a result of the
  sudden pressure enhancement at the bright point located at the root of
  the spicule. To show this, one dimensional (constant cross sectional)
  and time dependent hydrodynamic equations are solved numerically in
  the realistic solar atmosphere extending from the photosphere to
  the corona. Adiabatic motion is assumed. The pressure enhancement
  by a bright point at the base of the model atmosphere generates a
  shock wave. The shock gets stronger as it passes upward through the
  chromosphere and eventually collides with the chromosphere-corona
  interface which is a kind of a contact discontinuity. As the result,
  the interface begins to move upward. We identify the matter following
  behind this interface as the solar spicule. The model explains many
  observed features, such as the height and the density of the spicules,
  although such features have been hitherto considered not to be explained
  easily by shock theories.

---------------------------------------------------------
Title: On the Emission Spectra of Moustasches
Authors: Kitai, R.
1980jfss.conf..202K    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Morphological Study of the Solar Granulation - Part One -
    Dark Dot Formation in the Cell
Authors: Kitai, R.; Kawaguchi, I.
1979SoPh...64....3K    Altcode:
  High resolution images of the solar granulation show the presence of
  the small dot-like dark regions in the granulation cells. From the
  study of the characteristics of these dark regions, it is found that
  the dark regions are formed without any relations to the presence of
  the magnetic field. Moreover, it is observed that a granulation cell
  splits in a few minutes after the formation of the dark regions in the
  cell. Similarities and differences between the granules with the dark
  regions and the so-called exploding granules are discussed.

---------------------------------------------------------
Title: An Interpretation of Hydrogen and Helium Line Spectra of the
    Loop Prominence Observed on November 3, 1973
Authors: Kureizumi, T.; Kubota, J.; Tamenaga, T.; Maeda, K.; Kawaguchi,
   I.; Kitai, R.
1977PASJ...29..129K    Altcode:
  The H I, He I, and He ii emission lines of the loop prominence observed
  on November 3, 1973 in the rapidly developing phase are analyzed. The
  difference in widths of these lines suggests they do not originate
  in the same volume. The estimated Te (8000-9000 K) and e ( 2x 1012
  cm-3) in the loop from the Balmer lines do not change appreciably with
  time everywhere in the loop during our observation ( UT). The degree
  of ionization of hydrogen is estimated to be in the range of 0.8 to
  1.0. The ionizing mechanism may be attributed to the UV radiation (
  912A) from the underlying flare region. Local thermodynamic equilibrium
  (LTE) is approximately established in the excited levels of He I,
  but the singlet levels are somewhat overpopulated. The UV radiation
  field ( ) from the surrounding coronal condensation is estimated from
  microwave and X-ray flux measurements of SOLRAD 9. The ionization of
  He I (ionization degree 0.1-0.2) is mainly controlled by UV radiation
  from the coronal condensation. An adequate thread structure model of
  the loop prominence is suggested. Key words: Coronal condensation;
  Loop prominence; Spectra.

---------------------------------------------------------
Title: The velocity field associated with the birth of sunspots.
Authors: Kawaguchi, I.; Kitai, R.
1976SoPh...46..125K    Altcode:
  A velocity field is found to occur prior to the birth of sunspots or
  during the rapidly developing phase of new spots. Fraunhofer lines
  are always shifted redwards in the observed active regions which are
  situated at various distances from the disk center. The velocity
  amplitude derived from Na I D1-line, λ 5895.940, amounts to, at
  maximum, 1.5 km s<SUP>−1</SUP> which is always a little larger than
  that derived from the weaker line, NI I λ 5892.883. The velocity field
  disappears when the spot ceases to grow. The lifetime of the velocity
  is, at least, 1 hr. The velocity field is interpreted in terms of the
  continuous downward flow in the process of formation of sunspots.

---------------------------------------------------------
Title: Photospheric Velocity Field Associated with Moustaches
Authors: Kitai, R.; Kawaguchi, I.
1975SoPh...44..403K    Altcode:
  The photospheric velocity field was observed in an active region which
  was prolific in moustaches. It is shown that the moustaches occur at
  the locations where the sign of the line-of-sight velocity changes,
  and that the extension of the velocity field is large (≈10<SUP>4</SUP>
  km) compared with the dimension of moustaches.

---------------------------------------------------------
Title: The Brightening of Sunspot Umbra Observed on 29 October, 1972
Authors: Kubota, J.; Tamenaga, T.; Kawaguchi, I.; Kitai, R.
1974SoPh...38..389K    Altcode:
  Brief descriptions are given of the spectroscopic and the monochromatic
  observations of the umbral brightening on 29 October, 1972. The source
  of the brightening is attributed to the kinetic energy of the infalling
  coronal matter with a final velocity of 200 km s<SUP>−1</SUP>,
  into the umbral gas. The spectra of this brightening reveal many
  hydrogen and metallic emission lines. The variety of the widths of
  these lines indicates the existence of complex nonthermal velocity
  field and of the stratification of various emitting conditions in the
  umbral brightening. The kinetic energy of the falling matter would be
  expended not only for producing the emissions, but also for exciting
  the complex velocity field of nonthermal motion.