Author name code: hiei
ADS astronomy entries on 2022-09-14
author:"Hiei, Eijiro"
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Title: The IAU and Solar Eclipses
Authors: Pasachoff, Jay M.; Hiei, Eijiro; Perez, Cielo
Bibcode: 2019IAUS..349..459P
Altcode:
We describe the history of solar-eclipse supervision since the formation
of the International Astronomical Union, as the supervising body morphed
from a full commission to a subcommission to its current status as an
Inter-Divisional Working Group of the Education, Outreach and Heritage
Division and the Sun and Heliosphere Division.
Title: The early years of solar research in Japan
Authors: Hiei, E.
Bibcode: 2011ASInC...2..355H
Altcode:
The early years of solar research in Japan are described in the order
from the solar core to the corona. The contents are as follows; solar
neutrino problem, helioseismology, solar dynamo, photosphere, sunspots,
chromosphere, flares, prominence, corona, total solar eclipses, radio
observations, space observations, observatories, archival solar data,
and prospect.
Title: Comparison of the Vector Magnetograms taken with the SFT/MTK
and the SST/KSW
Authors: Hagino, M.; Nakatani, Y.; Ishii, T. T.; Hanaoka, Y.; Sakurai,
T.; Hiei, E.; Suzuki, D.
Bibcode: 2009ASPC..405..393H
Altcode:
We carried out a detailed comparison between the vector magnetograms
obtained with the Solar Flare Telescope (SFT/MTK) of the National
Astronomical Observatory of Japan and those obtained with the
Sextuple Solar Telescope (SST/KSW) of the Kawaguchi Science Museum
(the former name is the Kawaguchi Science World). We investigated
various characteristics of the errors in the Stokes parameters for each
instrument. The level of noise due to seeing effects in the SST/KSW
magnetograms is higher than in the SFT/MTK magnetograms. On the other
hand, we found that about 60% of the data pixels have the same sign
of current helicity α in these magnetograms. We will discuss the
possibility and limitations of the magnetic field studies using these
magnetograms.
Title: Scientific Dissemination of Eclipse Events in Japan
Authors: Iizuka, Y.; Agata, H.; Oe, M.; Hiei, E.
Bibcode: 2006SunGe...1b..61I
Altcode: 2006SunGe...1...61I
In order to increase citizen's interest and concern on scientific
activity and technology, it is important for scientists to make
outreach activity on an occasion of astronomical events. In this paper
we describe our experience on dissemination of total solar eclipse
events in Japan.
Title: Unusual spectral absorption observed in the 16 August 1989
limb flare
Authors: You, Jianqi; Li, Hui; Hiei, Eijiro
Bibcode: 2004SoPh..223..169Y
Altcode:
A relative complete set of He I 10830 Å profiles and their coincident
slit-jaw Hα images of the large limb flare (2N/X20) of 16 August
1989 were observed by the solar spectrograph at Purple Mountain
Observatory. In addition to the unusually broadened spectral profiles
observed in the impulsive phase, more than half of the observed He I
10830 Å profiles are characterized by central reversals, which were
detected not only in the impulsive phase but also in the late decaying
phase. The central-reversed profiles may exist at different heights,
ranging from the solar limb to (3-4) × 104 km above. The
absorption varies with time and position, with a typical lifetime
and size of several minutes and 5-6 arc sec, respectively. Depths
of the absorption profiles also change clearly. The absorptions
are usually deeper at the loop footpoint near the solar limb and
shallower at loop-top. However, the most unusual feature is that all
the line-center wavelengths of them show no shift relative to that of
the quiet chromosphere near the limb, implying the apparent velocities
are zero while the associated emission profiles have different apparent
velocities. Theoretical simulations demonstrate that the Doppler widths
of the absorptions are in the range of (0.35-0.5)Å and increase with
height, and the source functions are (0.11-0.3) times the disk center
intensity. However, the absorptions have a relative large range of
optical thickness (0.1-1.3) in the I3 component of the He I
10830 Å triplet. We have not observed such absorption in other limb
flares, including the SB/X2.9 flare of 17 August 1989 that occurred
in the same active region as the studied one (NOAA 5629). Our studies
show that the absorption could not result from he scattering by the
telluric atmosphere or from normal chromospheric absorption. This unique
phenomenon may be related to extra intense X-ray flux and caused by
diffuse and non uniform materials dissociated from the flare instead
of self-absorption of the flare.
Title: Unusually Broadened Spectral Profiles Observed in Solar
Prominences
Authors: Li, Hui; You, Jian-Qi; Hiei, Eijiro
Bibcode: 2004ChJAA...4..377L
Altcode:
After surveying the spectra of 39 prominences observed by
the Multi-channel Infrared Solar Spectrograph at Purple Mountain
Observatory and the 25 cm coronagraph at the Norikura Solar Observatory,
we found that about 28% of them show small spatial scale (6''-8'')
and short time scale (tens of seconds to a few minutes), unusual large
broadening and large shift velocities in spectral lines including Hα,
Hβ, hep, \cah, \cak, \caii, hed\ and hei. We present in detail two
typical events observed respectively on 2002 May 27 and 1981 August
2. The full-width at half maximum of the widest profile of the 2001
prominence is 1.8 Å for Hα and 2.9 Å for hei, while that of the
1981 prominence is 5.3 Å for Hβ, 3.6 Å for \cak, 4.0 Å for \cah
and 2.8 Å for hed. Such broadenings generally occur at a level of
several-thousand kilometers above the chromosphere. Further, most of
these prominences manifest a rotation of (0.4-1.35)×10-2
rads pointing to the Sun and large line-of-sight velocities of 20-200
kms. Some of these events correspond in time to an enhancement or a
small peak in the GOES X-ray flux, indicating the existence of high
energy process at work. These prominences generally display discernible
changes in the Hα morphology around the time of large broadening,
but do not show Hα brightening or overall eruption except for a few
small surge-like events, hence, they are hardly observed in daily Hα
patrols. According to the characteristics of their Hα structures and
spectral properties, we infer these events are small-scale eruptions
similar to nano-flares, which may contribute to the mass and energy
transported into the corona. Large turbulent velocities of 25-120 kms
are responsible for the observed broadenings.
Title: Unusual Spectral Absorption Observed in a Limb Flare
Authors: Li, H.; You, J. Q.; Hiei, E.
Bibcode: 2004cosp...35.1634L
Altcode: 2004cosp.meet.1634L
A relative complete set of HeI 10830 Å profiles and their coincident
slit-jaw Hα images of the large limb flare (2N/X20) of 16 August
1989 were observed by the solar spectrograph at Purple Mountain
Observatory. In addition to the unusually broadened spectral profiles
observed in the impulsive phase, more than half of the observed HeI
10830 Å profiles are characterized by central reversals, which were
detected in not only the impulsive phase but also the late decaying
phase. The central-reversed profiles may exist at different heights,
ranging from the solar limb to (3--4)×104km above. The
absorption varies with time and position, with a typical lifetime
and size of several minutes and 5''-6'', respectively. The depths
of the absorption profiles also change obviously. The absorptions
are usually deeper at the loop footpoint near the solar limb and
shallower at loop-top. However, the most unusual feature is that all
the line center wavelengths of them show no shift relative to that of
the quiet chromosphere near the limb, implying the apparent velocities
are zero while the associated emission profiles have different apparent
velocities. Theoretical simulations demonstrate that the Doppler widths
of the absorptions are in the range of (0.35--0.5)Å and increase with
height, and the source functions are (0.11--0.3)Ic0. However,
the absorptions have a relative large range of optical depth (0.1--1.3)
in the I3 component of HeI 10830 Å triplet. We have not
observed such absorption in other limb flares, including the SB/X2.9
flare of 17 August 1989 occurred in the same active region as the
studied one (NOAA 5629). Our studies manifest that the absorption could
not resulted from the scattering of telluric atmosphere and normal
chromospheric absorption. This unique phenomenon may be related to
extra intense X-ray flux and caused by diffuse and nonuniform materials
dissociated from the flare instead of self-absorption of the flare.
Title: The White-Light Limb Flare of 16 August 1989 and its
Chromospheric Counterpart
Authors: You, Jianqi; Hiei, Eijiro; Li, Hui
Bibcode: 2003SoPh..217..235Y
Altcode:
After carefully comparing the white-light (5600±00 Å) and the
slit-jaw Hα images (0.5 Å passband) of the 2N/X20 white-light flare
of 16 August 1989, we found that the Hα counterpart identification of
the bright kernels in continuum by Hiei, Nakagomi, and Takuma (1992)
was incorrect. Now we come to the conclusion that none of the two
white-light kernels has a corresponding bright Hα area. Moreover,
the loop shapes in white-light are also different from those in
Hα. Hα loops rose more rapidly than white-light loops. However, their
height-time variations on the whole are similar. This indicates that
the continuum and chromospheric emissions of the flare presumably come
from different plasmas, but may be modulated by some mutual factors,
such as large-scale magnetic fields. Analysis of the He i 10 830
Å spectra taken simultaneously with the slit-jaw Hα images shows
that the line-center intensity of He i 10 830 Å doesn't have a good
correlation with the intensity of nearby continuum, which supports the
above conclusions. In addition, the electron density at the white-light
loop top estimated from the continuum around 5600 Å and 10 830 Å is
as high as 1012-1013 cm−3.
Title: The flare of 1991 June 4 (importance 3B) and the associated
Moreton wave
Authors: Yamaguchi, Kisuke; Sakurai, Takashi; Irie, Makoto; Kumagai,
Kazuyoshi; Hagino, Masaoki; Miyashita, Masakuni; Shiomi, Yasuhiko;
Hiei, Eijiro
Bibcode: 2003RNAOJ...6..101Y
Altcode:
We observed a Moreton wave associated with a flare of importance 3B
in the NOAA region 6659 on 1991 June 4. The Moreton wave was emitted
from a flare bright point and initially showed the form of a loop. The
speed of the Moreton wave was initially 1500 km s-1 and
was later accelerated to 1800 km s-1. This acceleration
may be due to the propagation of the wave into a coronal hole (with
low density and high Alfvén velocity.
Title: White Light Flare at the Solar Limb
Authors: Hiei, E.; You, Jianqi; Li, Hui
Bibcode: 2003JKAS...36S..45H
Altcode:
No abstract at ADS
Title: Education and Understanding of Astronomy through Total Solar
Eclipses
Authors: Hiei, E.; Takahashi, N.; Iizuka, Y.
Bibcode: 2003ASPC..289..137H
Altcode: 2003aprm.conf..137H
A total solar eclipse has a great impact on ppeople, and hence there
are very old historic records in China, Mesopotamia, etc. The impact
still does not change in present times, and inspires wonder in us. The
spectacular and magnificent event at a total solar eclipse appeals
to our scientific thinking and sensitive feelings. Every one thinks
about what nature is. A total solar eclipse is therefore a good and
effective opportunity for education and understanding of astronomy.
Title: Line Broadening Observed in Solar Prominences
Authors: Li, Hui; You, Jianqi; Hiei, Eijiro
Bibcode: 2003IAUJD...7E...4L
Altcode:
Unusual line broadenings were observed in solar prominences by the
Multi-channel Infrared Solar Spectrograph (MISS) at Purple Mountain
Observatory China and Solar Coronagraph at Norikura Solar Observatory
Japan. Line profiles including H-alpha CaII 8542 HeI 10830 and D3 were
analyzed. All the prominences presented here show more or less broadened
line profiles with full-width at half maximum (FWHM) in the range of
1.6 Angstrom -2.5 Angstrom which last for about 20--40 minutes. The
spatial size of the prominence showing line broadening is about 6--8
arc sec. In addition line shift may simultaneously exist with line
broadening. The results show that the unusual line broadenings are
sometimes temporally consistent with soft X-ray increase observed by
GOES. This indicates that there may exist high energy process in solar
prominences. The broadening are frequently associated with active
regions instead of solar flares. However the unusual broadening may
be followed by surge-like structures or sprays. Meanwhile the tilted
spectrograms observed imply that solar prominence rotates in its rising
process and show the thread structure of prominence clearly
Title: On the formation of a helmet streamer on January 24, 1992 at
the south-west limb
Authors: Singh, Jagdev; Sakurai, T.; Ichimoto, K.; Hiei, E.
Bibcode: 2000BASI...28...33S
Altcode:
We have analysed the soft X-ray images of the sun obtained with
the YOHKOH satellite, white light coronal images observed at Mauna
Loa and H-alpha pictures of the sun taken at Mitaka and Kodaikanal
to study helmet streamers. We find that heating of a filament and
subsequent brightening in X-rays, and eruption in the region lead to
the formation of the helmet streamer on January 24, 1992. In another
event of February 24, 1993, only the brightening and eruption-like
expansion of the brightening in soft X-rays lead to the formation of
the streamer. No H-alpha filament was seen in this region before and
after the event of brightening in soft X-rays and formation of streamer
on February 24, 1993. We, therefore, postulate that the plasma in the
streamer comes from the solar surface during the X-ray eruption, and
magnetic field of the region perhaps helps in containing the plasma
and the formation of the streamer.
Title: Results of the Observations of the Total Solar Eclipses of
1994 1995, 1997 1998, and 1999
Authors: Hiei, E.; Takahashi, N.; Iizuka, Y.; Eclipse Group Of Meisei
University
Bibcode: 2000ASPC..205..181H
Altcode: 2000ltse.conf..181H
The eclipse group of Meisei University observes polar plumes at the
total solar eclipses of 1994, 1995, 1997, and 1998, and the widths,
electron density, and temperature of the polar plumes are reported.
Title: Ground-Based and SOHO Observations of Polar Plumes During
Eclipse
Authors: Hiei, E.; Takahashi, N.
Bibcode: 2000AdSpR..25.1887H
Altcode:
Polar plumes are observed in polar regions during the minimum activity
phase. Their existence, stability, and curved structure remain unsolved
problems. Characteristics of polar plumes observed at the 4 solar
eclipses of 1994, 1995, 1997, and 1998 are described. Temperature of
polar plumes, derived from the density scale height, is about 106 K
Title: Temperatures of Pre-Flare and Flaring Loops Observed with
the Yohkoh Soft X-Ray Telescope
Authors: Yasuno, S.; Hiei, E.; Hara, H.; Watanabe, T.
Bibcode: 2000AdSpR..25.1805Y
Altcode:
We statistically investigate thermal characteristics of soft X-ray
coronal loops in the pre-flare and flaring stages using the data
observed between January 1992 and December 1992 with the soft X-ray
telescope on board the Yohkoh satellite. The data cover the pre-flare
phase in the periods of 30-90 minutes preceding the flares, the rising
phases, and the peaks of flares in X- ray intensity, and the beginnings
of the decay phases. We compare the thermal characteristics of soft
X-ray coronal loops before they flare and those at the peaks of flares,
and we find that the loops having higher temperatures in the pre-flare
stages produce bigger and higher temperature flares later
Title: A flare-associated filament eruption observed in soft X-rays
by YOHKOH on 1992 May 7
Authors: Khan, Josef I.; Uchida, Yutaka; McAllister, Alan H.;
Mouradian, Zadig; Soru-Escaut, Irina; Hiei, Eijiro
Bibcode: 1998A&A...336..753K
Altcode:
Yohkoh soft X-ray image data prior to a filament activation and eruption
on 1992 May 7 reveal the presence of a bright, filamentary soft X-ray
structure apparently lying low under an arcade of soft X-ray loops
from which the eruption later originated. This filamentary soft X-ray
feature was coexistent and partially co-spatial along the line-of-sight
direction with a dark He I 1083 nm filamentary structure (which was
similar in appearance to an Hα dark filament observed earlier). Prior
to the start of the flare the apparently low-lying filamentary soft
X-ray structure disappeared, but a bright linear feature was then seen
just below several clearly visible overlying loops, consistent with
the filamentary soft X-ray feature having risen in altitude. At the
same time the Hα dark filament became elevated and overlapped well,
along the line-of-sight direction, with the elevated linear soft X-ray
feature. Some of the overlying loops brightened in soft X-rays at the
time the Hα data show the Hα filament in an elevated position and
rising, (but before the Hα dark filament disappearance). The overlying
soft X-ray loops also showed an increase in temperature and emission
at the time of the filament activation. Eventually the elevated,
filamentary soft X-ray feature disappeared and several apparently
cusped shaped loops were then observed in the vicinity. Within several
minutes of this time the soft X-ray flare occurred. The series of
Yohkoh soft X-ray images for this event together with supporting data
from ground-based observatories strongly suggest that many features
of the magnetic field changes associated with the eruption of the
filament were seen in soft X-rays. Moreover the observations indicate
that the filament and overlying arcade should be considered to be
semi-independent structures that can interact with each other, rather
than as parts of a large single structure, as is often assumed. We also
find two types of cusped loops in this event. The first type consists
of several distinct narrow cusped loops prior to the flare, while the
second type consists of diffuse cusped loop structures which appear
to lie above the brightest parts of the bright arcade during gradual
phase of the flare. Evidence is also presented which indicates that a
nearby parasitic polarity emerging flux region may have played a role
in destabilizing the arcade region, causing the filament activation,
eruption and flare. The changes in the magnetic field extend beyond
the flaring arcade to include the creation of a transient coronal hole
and a dark coronal channel near the arcade.
Title: The Filament Disappearance of 7 May 1992 (the Ebi)
Authors: Mouradian, Z.; Soru-Escaut, I.; Hiei, E.; McAllister, A. H.;
Shibasaki, K.; Ohyama, M.; Khan, J. I.; Uchida, Y.
Bibcode: 1998SoPh..180..313M
Altcode:
The 7 May 1992 filament disappearance in the low corona is analyzed. The
cool and hot components of this event are studied, using Hα, soft X-ray
and radio data. We first show the general effect of the disparition
brusque (DB) on the life of the filament, which was a quiescent filament
in the vicinity of an active region, and then give the history of the
development of the 7 May event. The main stages of the event are: (i)
the formation of hot arches spanning the cool filament; (ii) rise of
the filament, with plasma ejection into the corona, in which we note
some spreading of loops from the main body, with two distinct rising
velocity phases of the Hα filament; (iii) formation of X-ray arches
below the filament, the foot points of the arcades being two-ribbon
Hα flare patches. The dynamics of Hα and X-rays features are given.
Title: Polar plumes of the 1994, 1995 and 1997 total solar eclipses
Authors: Takahashi, N.; Hiei, E.
Bibcode: 1998ESASP.421..337T
Altcode: 1998sjcp.conf..337T
No abstract at ADS
Title: The Filament Disappearance of may 7, 1992
Authors: Hiei, E.; Mouradian, Z.; Soru-Escaut, I.; McAllister, A. H.;
Shibasaki, K.; Ohyama, M.
Bibcode: 1998ASSL..229...95H
Altcode: 1998opaf.conf...95H
No abstract at ADS
Title: Prominence Disappearance Related to CMEs
Authors: Hiei, E.
Bibcode: 1998ASPC..150..380H
Altcode: 1998npsp.conf..380H; 1998IAUCo.167..380H
No abstract at ADS
Title: Coronal Loops Above a Sunspot Region
Authors: Fang, C.; Tang, Y. H.; Ding, M. D.; Zhao, J.; Sakurai, T.;
Hiei, E.
Bibcode: 1997SoPh..176..267F
Altcode:
By analysing the data of Yohkoh soft X-ray images, vector magnetograms
and 2D spectral observations, coronal loops above a large sunspot on
16-19 May 1994 have been studied. It is shown that the loops follow
generally the alignment of concentrated magnetic flux. The results
indicate that the soft X-ray emission is low just above the sunspot,
while some loops connecting regions with opposite magnetic polarities
show strong soft X-ray emission. Especially, the part of the loops
near the weaker magnetic field region tends to be brighter than the
one near the stronger magnetic field. The temperature around the top
of the loops is typically ∼3 × 106 K, which is higher
than that at the legs of the loops by a factor of 1.5-2.0. The density
near the top of the loops is about 5 x 109 cm-3,
which is higher than that of the leg parts of the loops. These loops
represent probably the sites where strong magnetic flux and/or current
are concentrated.
Title: Electron Temperature of Solar Flares Derived from Helium-Like
Sulphur Lines
Authors: Yuda, Sayuri; Hiei, Eijiro; Takahashi, Masaaki; Watanabe,
Tetsuya
Bibcode: 1997PASJ...49..115Y
Altcode:
The maximum temperatures and emission measures reached in solar flares
were obtained from helium-like sulphur lines, which were observed by
the Bragg Crystal Spectrometer on board Yohkoh. A very weak dependence
of the maximum temperature against the soft X-ray intensity was
found. Similar multi-thermal characteristics prevailed in flares
irrespective of the flare intensity, suggesting that the solar flare
is a homogeneous phenomenon in the solar atmospheres.
Title: Formation of an X-ray helmet structure after a coronal mass
ejection
Authors: Hiei, E.
Bibcode: 1997MmSAI..68..491H
Altcode:
No abstract at ADS
Title: Results from the coronal observations of the 1994 and 1995
total solar eclipse.
Authors: Hiei, E.; Inoue, K.; Takahashi, N.
Bibcode: 1997ASIC..494....1H
Altcode: 1997topr.conf....1H
In order to know the three-dimensional structure of the solar corona,
collaboration of both the ground-based and soft X-ray observations
is needed. Comparison of both observations at the 1994 and 1995 total
solar eclipse is described, and their coronal streamers are discussed.
Title: YOHKOH Observations of Fe XXVI X-Ray Line Emission from
Solar Flares
Authors: Pike, C. D.; Phillips, K. J. H.; Lang, J.; Sterling, A.;
Watanabe, T.; Hiei, E.; Culhane, J. L.; Cornille, M.; Dubau, J.
Bibcode: 1996ApJ...464..487P
Altcode:
We report on observations from the Bragg Crystal Spectrometer (B CS)
on board the Japanese solar flare spacecraft Yohkoh showing Fe XXVI
Lyα X-ray line emission at 1.78 Å. Some 75 events over a 2 yr period
between 1991 December 6 and 1993 December 31 have been analyzed. The
greater sensitivity of the BCS compared with previous instruments has
enabled such emission to be detected from a wider group of flares than
has previously been possible. The likelihood of detecting Fe XXVI lines
in a flare is found to increase sharply with the electron temperature
obtained from the Fe XXV line spectrum, also observed by the BCS,
and with GOES X-ray class. The width of the Lyα1, line,
measured after the impulsive stage, is greater than that determined by
thermal Doppler broadening, but this is explained by the nonzero spatial
extent of flares. Electron temperatures from the intensity ratio of a
nearby feature due to Fe XXV dielectronic satellites and the Fe XXVI
Lyα1 line are obtained from new atomic parameters from
the superstructure code, details of which are described. This revises
earlier calculations that have been extensively used. Comparison
of these temperatures with those from the Fe XXV spectra provides
evidence for a single loose grouping of flares, with the difference
between the two temperatures ranging from nearly zero to about 20 MK. A
"superhot" component would seem to be more or less developed according
to whether the temperature difference is large or nearly zero. Flares
at both extremes are examined in detail. The gradually varying part
of the 14-33 keV X-ray emission for these events, as observed by the
Hard X-ray Telescope on Yohkoh, has a hardness ratio corresponding
to temperatures and emission measures similar to those from Fe XXVI
line ratios, pointing to a common origin for their emission. Many of
the flares studied occurred in particular active regions with great
magnetic complexity, although Fe XXVI flares do not seem to be a
distinct class within large X-ray flares.
Title: Fe XXVI line emission observed by YOHKOH
Authors: Pike, C. D.; Pillips, K. J. H.; Lang, J.; Sterling, A.;
Watanabe, T.; Hiei, E.; Culhane, J. L.
Bibcode: 1996AdSpR..17d..51P
Altcode: 1996AdSpR..17...51P
Observations from the Bragg Crystal Spectrometer (BCS) on board
the Japanese solar flare space-craftYohkoh showing Fe xxvi Ly-alpha
X-ray line emission at about 1.78 Angstroms are reported. Some 75
events over a two-year-long period between December 1991 and December
1993 have been analyzed. The greater sensitivity of the BCS compared
with previous instruments has enabled such emission to be detected
from a wider group of flares than has previously been possible. The
likelihood of detecting Fe xxvi lines in a flare is found to increase
sharply with the electron temperature obtained from the Fe xxv line
spectrum, also observed by the BCS, and with GOES X-ray class. The
width of the Lyalpha_1 line, measured after the impulsive stage, is
rather greater than that determined by thermal Doppler broadening,
and if the excess broadening is attributed to turbulence, velocities
of up to 70 km s^-1 are indicated. Comparison of electron temperatures
obtained from the Fe xxvi spectrum with Fe xxv temperatures provides
evidence for a single loose grouping of flares, with the difference
between the two temperatures ranging from nearly zero to about 20 x
10^6K. A ``superhot'' component would seem to be more or less developed
according as the temperature difference is large or nearly zero.
Title: Coronal structure and heating: comparison between SXT/Yohkoh
observations of an active region and magnetogram
Authors: Cheng, C. -C.; Dere, K. P.; Wu, S. T.; Hagyard, M. J.;
Hiei, E.
Bibcode: 1996AdSpR..17d.205C
Altcode: 1996AdSpR..17..205C
We have studied the magnetic structure in AR 7150 (S09E06) observed on
29 April 1992 by the Soft X-Ray Telescope (SXT) on Yohkoh. The observed
X-ray images are compared with force-free magnetic fields with different
values of alpha, extrapolated from the MSFC photospheric magnetogram
observed at the same time. The results show that the magnetic field
of the active region is not potential. Different groups of loops are
characterized by different values of alpha. Bright loops correspond to
field with large alpha, indicating twisting of the loop. However, there
is no obvious correlation between the brightness of individual loops
with the amount of twist. Further investigation of the magnetic state of
the loop structure requires accurate nonlinear force-free calculations.
Title: Structure and evolution of post-flare loops: analysis of
YOHKOH and MSDP observations
Authors: Schmieder, B.; Heinzel, P.; Wiik, J. E.; Lemen, J.; Hiei, E.
Bibcode: 1996AdSpR..17d.111S
Altcode: 1996AdSpR..17..111S
Using coordinated observations of the June 26 1992 post-flare loops
(Yohkoh-SXT and MSDP at Pic-du-Midi), we have analyzed the physical
conditions in both hot and cool loops and studied their spatial
structure and temporal evolution. Coalignment of high-resolution images
from SXT and MSDP indicates that the cool Hα loops are located just
below the hot ones and that the whole loop system grows in time with
a velocity 1.4 km s^-1. The temperature of hot loops as derived from
SXT data amounts to 5 x 10^6 K, while the cool loops have temperatures
around 10^4 K. The electron density of hot loops was estimated from
SXT emission-measure analysis to 7 x 10^9 cm^-3, while Hα integrated
intensity gives an electron density in cool loops of 2.2 x 10^10
cm^-3. With these plasma parameters we have solved the energy equation
in order to estimate the cooling time. The basic result of this work
is that the cooling time is comparable to the characteristic growing
time of the loop system (~ 1500 - 2000 sec), which is in agreement
with the scenario of the post-flare loop system development.
Title: New observational facts about solar flares from ground-based
observations
Authors: Sakurai, T.; Hiei, E.
Bibcode: 1996AdSpR..17d..91S
Altcode: 1996AdSpR..17Q..91S
Recent observational studies on solar flares by using ground-based
instruments are reviewed. Magnetic field measurements are being carried
out in many observatories, and conclusive evidence on the storage of
magnetic energy and its release at flares has accumulated. On the other
hand it is interesting that some controversial results were reported
in regard to the change in magnetic fields associated with flares.
Title: Solar flare, coronal and heliospheric
dynamics. Proceedings. E2.2 Symposium of COSPAR Scientific Commission
E which was held during the Thirtieth COSPAR Scientific Assembly,
Hamburg (Germany), 11 - 21 Jul 1994.
Authors: Culhane, J. L.; Hiei, E.
Bibcode: 1996AdSpR..17d....C
Altcode: 1996AdSpR..17.....C
The following topics were dealt with: solar flare studies, Yohkoh
observations of magnetic reconnection, high temperature plasma in solar
flares, hard X-ray fluxes in solar flares, particle acceleration during
flares, ground-based observations of flares, UV observations, radio
bursts, chromospheric condensations, energetic particle transport in
solar flares, solar active regions, coronal structure, solar magnetic
cycle, coronal holes, coronal dynamic phenomena, coronal magnetic
fields, heliosphere dynamics, Ulysses data, interplanetary magnetic
field, heliospheric density structure, signatures of fast coronal mass
ejections in the interplanetary space, interplanetary shock waves,
future missions and instrumentation.
Title: A spectral analysis of the 1974-10-11 white-light flare
Authors: Yin, Su-Ying; Fang, Cheng; Ding, Ming-De; Hiei, E.; Fu, Qi-Jun
Bibcode: 1996ChA&A..20..130Y
Altcode:
No abstract at ADS
Title: The solar corona at the 1994 eclipse.
Authors: Hiei, E.
Bibcode: 1996sube.conf...47H
Altcode:
No abstract at ADS
Title: Development of a Coronal Helmet Streamer of 24 January 1992
Authors: Hiei, E.; Hundhausen, A. J.
Bibcode: 1996mpsa.conf..125H
Altcode: 1996IAUCo.153..125H
No abstract at ADS
Title: Formation of an X-Ray Helmet Structure after a Coronal Mass
Ejection
Authors: Hiei, E.; Hundhausen, A. J.; Burkepile, J.
Bibcode: 1996ASPC..111..383H
Altcode: 1997ASPC..111..383H
SXT images, related to coronal mass ejections (CME), are studied, from
the "listing of Mauna Loa Mark-III white light mass ejection during
the Yohkoh period of observations (October 1991 through 1995)." Among
them, two events (30 Apr 1993 and 24 Jan 1992) clearly show a typical
helmet streamer, and one event (16 Jan 1993) shows dimming, which may
be due to coronal mass depletion.
Title: Declining Phase Coronal Evolution: The Statistics of X-ray
Arcades
Authors: McAllister, A. H.; Hundhausen, A. J.; Burkepile, J. T.;
McIntosh, P.; Hiei, E.
Bibcode: 1996mpsa.conf..123M
Altcode: 1996IAUCo.153..123M
No abstract at ADS
Title: Comparison between H-alpha and SXT images of 13/16 Jan. 1993.
Authors: Hiei, E.
Bibcode: 1996sube.conf...51H
Altcode:
No abstract at ADS
Title: Minor Photospheric and Chromospheric Magnetic Activity and
Related Coronal Signatures
Authors: Cauzzi, G.; Falchi, A.; Falciani, R.; Hiei, E.; Smaldone,
L. A.
Bibcode: 1996mpsa.conf..433C
Altcode: 1996IAUCo.153..433C
No abstract at ADS
Title: Ground-Based Solar Physics Research at Watukosek Solar
Observatory Lapan, Indonesia
Authors: Setiahadi, B.; Anwar, B.; Widodo, N.; Kambry, M. A.; Hiei, E.
Bibcode: 1996gbaa.conf...70S
Altcode:
No abstract at ADS
Title: Spectral Analysis of the White Light Flare on 1974OCT11
Authors: Yin, S. Y.; Fang, C.; Ding, M. D.; Hiei, E.; Fu, W. J.
Bibcode: 1995AcASn..36..279Y
Altcode:
No abstract at ADS
Title: An Unusual Behaviour of the White-Light Flare on 11 October,
1974
Authors: Fang, C.; Yin, S. Y.; Hiei, E.; Ding, M. D.; Fu, Q. J.
Bibcode: 1995SoPh..158..387F
Altcode:
It was found that in the spectrum of the white-light flare on 11
October, 1974, at the time of continuum maximum, the intensity of
K1 in the CaII K line increased very significantly and
reached nearly half of the continuum intensity. The duration of
this unusual increase is less than 4 min. It seems that existing
semi-empirical models can reproduce neither this characteristic nor
the chromospheric condensation.
Title: Temperature Structure of Active Regions Deduced from the
Helium-Like Sulphur Lines
Authors: Watanabe, Tetsuya; Haka, Hirohisa; Shimizu, Toshifumi; Hiei,
Eijiro; Bentley, Robert D.; Lang, James; Phillips, Kenneth J. H.; David
Pike, C.; Fludra, Andrzej; Bromage, Barbara J. I.; Mariska, John T.
Bibcode: 1995SoPh..157..169W
Altcode:
Solar active-region temperatures have been determined from the full-Sun
spectra of helium-like sulphur (SXV) observed by the Bragg Crystal
Spectrometer on board theYohkoh satellite. The average temperature
deduced from SXV is demonstrated to vary with the solar activity level:
A temperature of 2.5 × 106 K is derived from the spectra
taken during low solar activity, similar to the general corona, while
4 × 106 K is obtained during a higher activity phase. For
the latter, the high-temperature tail of the differential emission
measure of active regions is found most likely due to the superposition
of numerous flare-like events (micro/nano-flares).
Title: Declining Phase Coronal Evolution: The Statistics of X-ray
Arcades
Authors: McAllister, A. H.; Hundhausen, A. J.; Burkpile, J. T.;
McIntosh, P.; Hiei, E.
Bibcode: 1995SPD....26..602M
Altcode: 1995BAAS...27Q.961M
No abstract at ADS
Title: A study of the white light flare of 1974 September 10
Authors: Hu, Ju; Fang, Cheng; Ding, Ming-de; Hiei, E.
Bibcode: 1995ChA&A..19..215H
Altcode:
We have made a detailed analysis of the spectral data of the white light
flare of 1974 September 10. Using a non-LTE theory we have calculated a
semi-empirical atmosphere model and its radiation loss. From the spectra
we found (1) a Balmer jump amounting to 11% at the flare maximum, (2)
strong and broad Balmer line emission, the width of the higher order
terms reaching a minimum between main quantum number 8 and 9, and (3)
the continuum emission peaking at about the same time as the microwave
emission, a few minutes before the H α flare maximum. These
features may be common to all white light flares. Analysis shows that
the heating in the photosphere and lower chromosphere is probably
produced by backwarming of the enhanced emission in the upper
chromosphere, while the heating of the upper chromosphere is probably
due to bombardment by high-energy electron beams.
Title: Solar Flare Telescope at Mitaka
Authors: Sakurai, Takashi; Ichimoto, Kiyoshi; Nishino, Yohei; Shinoda,
Kazuya; Noguchi, Motokazu; Hiei, Eijiro; Li, Ting; He, Fengbao; Mao,
Weijun; Lu, Haitian; Ai, Guoxiang; Zhao, Zhaowang; Kawakami, Singo;
Chae, Jong-Chul
Bibcode: 1995PASJ...47...81S
Altcode:
A new solar telescope constructed recently at Mitaka, Tokyo, is
described. This instrument, called the Solar Flare Telescope, comprises
four telescopes which respectively perform: (1) magnetic-field vector
measurements, (2) Doppler-velocity measurements, (3) Hα observations,
and (4) continuum observations. The instrument has been operated as
a ground-based support for the X-ray satellite Yohkoh launched in
1991 August.
Title: Relation between Cool and Hot Post-Flare Loops of 26 June
1992 Derived from Optical and X-Ray (SXT-YOHKOH) Observations
Authors: Schmieder, B.; Heinzel, P.; Wiik, J. E.; Lemen, J.; Anwar,
B.; Kotrc, P.; Hiei, E.
Bibcode: 1995SoPh..156..337S
Altcode:
We have analyzed the physical conditions of the plasma in post-flare
loops with special emphasis on dynamics and energy transport using
SXT-data (hot plasma) and optical ground-based data from Pic du Midi,
Wrocław, and Ondřejov (cool plasma). By combining the Hα observations
with the SXT images we can understand the relationship between cool and
hot plasmas, the process of cooling post-flare loops and the mechanism
which maintains the long duration of these loops. Using recent results
of NLTE modeling of prominence-like plasmas, we derive the emission
measure of cool Hα loops and this gives us a realistic estimate of
the electron density (2.2 × 1010 cm−3). Then,
by comparing this emission measure with that of hot loops derived from
SXT data, we are able to estimate the ratio between electron densities
in hot and cool loops taking into account the effect of geometrical
filling factors. This leads to the electron density in hot loops 7 ×
109 cm−3. We also derive the temperature of
hot X-ray loops (≃ 5.5 × 106 K), which, together with
the electron density, provides the initial values for solving the
time-dependent energy balance equation. We obtain the cooling times
which are compared to a typical growth-time of the whole loop system
(∼ 2000 s). In the legs of cool Hα loops, we observe an excess
of the emission measure which we attribute to the effect of Doppler
brightening (due to large downflow velocities).
Title: Ground-Based Image and Yohkoh Observations
Authors: Hiei, E.
Bibcode: 1995pist.conf..127H
Altcode:
No abstract at ADS
Title: X-ray bright points and high-speed wind streams: a preliminary
analysis from Yohkoh and Ulysses data
Authors: Poletto, G.; Suess, S. T.; Khan, J. I.; Uchida, Y.; Hiei,
E.; Neugebauer, M.; Goldstein, B. E.; Strong, K. T.; Harvey, K. L.
Bibcode: 1994ESASP.373..143P
Altcode: 1994soho....3..143P
No abstract at ADS
Title: Coordinated optical and YOHKOH observations of 26 June 1992
flare loops
Authors: Heinzel, P.; Kotrč, P.; Schmieder, B.; Hiei, E.; Anwar, B.
Bibcode: 1994SSRv...70..181H
Altcode:
Optical spectra of large flare loops were detected by the Ondřejov
Multichannel Flare Spectrograph (MFS) during coordinated observations
with MSDP at Pic du Midi (Hα) and the soft X-ray telescope (SXT)
on Yohkoh. The CCD video images taken by the MFS slit-jaw camera
document the time-development of the flare loops as seen through the
Hα filter. Preliminary analysis of the MSDP images shows the intensity
structure of the cool flare loops and their velocity fields. From the
spectra we can clearly see the intensity variations along the cool
loops. SXT images show the structure of hot X-ray loops similar to
that of cool loops. Special attention is devoted to the bright tops,
simultaneously observed in X-rays, Hα and other optical lines. Based
on a preliminary analysis of the optical spectra, we speculate about
possible mechanisms leading to an observed bright emission at the tops
of cool loops. We suggest that direct soft X-ray irradiation of cool
loops at their tops could be, at least partly, responsible for such
a strong brightening.
Title: Structure and development of quiet loops in the solar corona
Authors: Hiei, Eijiro
Bibcode: 1994SSRv...70..189H
Altcode:
X-ray emission from solar coronal loops changes on two different
timescales: a) flare loops and transient active region brightenings show
a rapid variability, b) quiet region loops are quasi-steady and change
only slowly with time. This different time behavior has been analyzed
on the basis of Yohkoh SXT observations and we report here on the
results from our analysis, mainly focussing on quiet loop variability.
Title: A Search for ``Black-Light Flares''
Authors: Driel-Gesztelyi, L. V.; Hudson, H. S.; Anwer, B.; Hiei, E.
Bibcode: 1994kofu.symp..375D
Altcode:
No abstract at ADS
Title: Temperature Analysis of the Post-Flare Loops of June 25-26,
1992
Authors: Anwer, B.; Hiei, E.; Hudson, H. S.; Acton, L. W.; Lemen,
J.; Metcalf, T. R.
Bibcode: 1994kofu.symp..137A
Altcode:
We have performed an analysis of temperatures and emission measures
of thermal plasma on a post--flare loop system following an X3.9
flare of June 25, 1992, at 20:14 UT in NOAA active region 7205 near
the west limb (N09, W67). The filter ratio method was applied to the
data sets taken using the Al 0.1 micron (thin Al) and Al 12 micron
(thick Al) filters of the Yohkoh Soft X-ray Telescope (SXT). We found
that the plasma temperature of the top of loops was in the range 5 -
8 x 10^6 K and log emission measure between 44.6 and 46.7 cm^(-3)
for data sets taken from 22:56:57 UT of June 25 to 09:00 UT of June
26. Furthermore, the occurrence of a C1-class flare at the top of the
flare loops increased the plasma temperature from 5.5 x 10^6 K to 6.6
x 10^6 K at 06:57:11 UT. The loops top was much brighter than the legs
and footpoints, with delta_T was about 0.1 x 10^6 K.
Title: A Yohkoh search for ``black-light flares''
Authors: van Driel-Gesztelyi, Lidia; Hudson, Hugh S.; Anwar, Bachtiar;
Hiei, Eijiro
Bibcode: 1994SoPh..152..145V
Altcode: 1994svs..coll..145V; 1994IAUCo.143..145V
Calculations which predict that a phenomenon analogous to stellar
negative pre-flares could also exist on the Sun were published by
Hénouxet al. (1990), and Aboudarhamet al., (1990), who showed that
at the beginning of a solar white-light flare (WLF) event an electron
beam can cause a transient darkening before the WLF emission starts,
under certain conditions. They named this event a "black light flare"
(BLF). Such a BLF event should appear as diffuse dark patches lasting
for about 20 seconds preceding the WLF emission, which would coincide
with intense and impulsive hard X-ray bursts. The BLF location would
be at (or in the vicinity of) the forthcoming bright patches. Their
predicted contrast depends on the position of the flare on the solar
disc and on the wavelength band of the observation.
Title: Electron precipitation and mass motion in the 1991 June 9
white-light flare
Authors: de La Beaujardiere, J. -F.; Canfield, R. C.; Metcalf, T. R.;
Hiei, E.; Sakurai, T.; Ichimoto, K.
Bibcode: 1994SoPh..151..389D
Altcode:
We use Hα line profiles as a diagnostic of mass motion and
nonthermal electron precipitation in the white-light flare (WLF) of
1991 June 9 01:34 UT. We find only weak downflow velocities (≈10 km
s−1) at the site of white-light emission, and comparable
velocities elsewhere.We also find that electron precipitation is
strongest at the WLF site. We conclude that continuum emission in this
flare was probably caused by nonthermal electrons and not by dynamical
energy transport via a chromospheric condensation.
Title: Very Impulsive Solar Flares Observed with the YOHKOH Spacecraft
Authors: Feldman, U.; Hiei, E.; Phillips, K. J. H.; Brown, C. M.;
Lang, J.
Bibcode: 1994ApJ...421..843F
Altcode:
Using X-ray data from two instruments aboard the Yohkho spacecraft,
launched in 1991 August to study solar high-energy phenomena, some 38
extremely impulsive flares of X-ray importance greater than C1 have
been identified and studied. Electron temperatures of these flares,
derived from Yohkoh Bent Crystal Spectrometer data, appear to decline
immediately after the intensity maximum is attained, implying that
energy input into the flaring plasma is reduced or possibly ceases
after this time. Images of these flares with the high-resolution Yohkoh
Soft X-ray Telescope show that, contrary to expectation if thermal
conduction is a significant cooling mechanism, the emitting regions of
tiny pointlike sources (volumes less than or = 3 x 1024cc)
within a loop structure. With mass loss along field lines eliminated
also, from a previous study, the chief energy-loss mechanism is
likely to be radiation, and if so a lower limit for the electron
density of approximately 1012/cc is imposed. This is only
compatible with values of the emission measure if the flare volume
is 3 x 1024cc, corresponding to a sphere of only 1790 km
in diameter.
Title: Structure and Development of Quiet Loops in the Solar Corona
(Invited)
Authors: Hiei, E.
Bibcode: 1994scs..conf..163H
Altcode: 1994IAUCo.144..163H
Solar coronal features seen in X-ray emission change on two different
timescales: a) flare loops and transient brightenings in active regions
show a rapid variability, b) quiet region loops are quasi-steady and
change only slowly with time. This different time behavior has been
analyzed on the basis of Yohkoh SXT observations. The author reports
the results, mainly focussing on quiet loop variability.
Title: Coronal Eruptive Events on April 4, and may 4, 1992
Authors: Sime, D. G.; Hiei, E.; Hundhausen, A. J.
Bibcode: 1994xspy.conf..197S
Altcode:
No abstract at ADS
Title: Reformation of a Coronal Helmet Streamer by Magnetic
Reconnection after a Coronal Mass Ejection
Authors: Hiei, E.; Hundhausen, A. J.; Sime, D. G.
Bibcode: 1994xspy.conf..205H
Altcode:
No abstract at ADS
Title: A Resonance Line Rations Method for Determining Flare
Temperatures Using YOHKOH BCS Spectra
Authors: Sterling, A. C.; Doschek, G.; Mariska, J. T.; Hiei, E.;
Watanabe, T.
Bibcode: 1994xspy.conf..127S
Altcode:
No abstract at ADS
Title: Study of the White Light Flare of 1974SEP10
Authors: Hu, J.; Fang, C.; Ding, M. D.; Hiei, E.
Bibcode: 1994AcASn..35..396H
Altcode:
No abstract at ADS
Title: Very Impulsive Flares Observed with YOHKOH
Authors: Feldman, U.; Hiei, E.; Phillips, K. J. H.; Lang, J.; Brown,
C. M.
Bibcode: 1994xspy.conf..269F
Altcode:
No abstract at ADS
Title: Temperature Structure of Active Regions Deduced from the
Helium-Like Sulphur Lines
Authors: Watanabe, T.; Hara, H.; Shimizu, T.; Hiei, E.; Mariska,
J. T.; Bentley, R. D.; Fludra, A.; Lang, J.; Phillips, K. J. H.;
Pike, C. D.; Bromage, B. J. I.
Bibcode: 1994xspy.conf...55W
Altcode:
No abstract at ADS
Title: Morphological Evolution of the Post-Flare Loops of June
25-26, 1992
Authors: Anwar, B.; Hiei, E.; Hudson, H. S.; Acton, L. W.; Metacalf,
T.; Lemen, J.; Martens, P.
Bibcode: 1994xspy.conf..121A
Altcode:
No abstract at ADS
Title: Very Impulsive Flares Observed with Yohkoh
Authors: Lang, J.; Feldman, U.; Hiei, E.; Phillips, K. J. H.; Brown,
C. M.
Bibcode: 1994emsp.conf..191L
Altcode:
No abstract at ADS
Title: Reformation of a coronal helmet streamer by magnetic
reconnection after a coronal mass ejection
Authors: Hiei, E.; Hundhausen, A. J.; Sime, D. G.
Bibcode: 1993GeoRL..20.2785H
Altcode:
A bright feature observed on Jan. 24-26, 1992 with the soft X-ray
telescope on the YOHKOH spacecraft and with the coronameter at the
Mauna Loa Solar Observatory assumed the appearance of a coronal helmet
streamer as it slowly expanded. Mauna Loa observations from Jan. 22-24
indicate that a prominence eruption and coronal mass ejection occurred
before this feature was seen. We interpret the Jan. 24-26 observations
as evidence for “reformation” of a magnetically closed helmet
structure as a consequence of magnetic reconnection that proceeded
along a vertical magnetic neutral sheet formed by the mass ejection.
Title: The 1992 January 5 Flare at 13.3 UT: Observations from YOHKOH
Authors: Doschek, G. A.; Strong, K. T.; Bentley, R. D.; Brown, C. M.;
Culhane, J. L.; Fludra, A.; Hiei, E.; Lang, J.; Mariska, J. T.;
Phillips, K. J. H.; Pike, C. D.; Sterling, A. C.; Watanabe, T.; Acton,
L. W.; Bruner, M. E.; Hirayama, T.; Tsuneta, S.; Rolli, E.; Kosugi,
T.; Yoshimori, M.; Hudson, H. S.; Metcalf, T. R.; Wuelser, J. -P.;
Uchida, Y.; Ogawara, Y.
Bibcode: 1993ApJ...416..845D
Altcode:
We discuss X-ray spectra and soft X-ray images of an M1.9 flare that
occurred on 1992 January 5 near 13.3 UT. These data were obtained
with instrumentation on the Japanese Yohkoh spacecraft. They cover
the entire rise phase of the flare. To supplement these data we have
ground-based magnetograms and Hα spectroheliograms. We calculate
the electron temperature and emission measure of the flare as a
function of time during the early rise phase using X-ray spectral
line intensities and line ratios. Using spectral line widths, line
profile asymmetries, and wavelength shifts due to the Doppler effect,
we calculate the dynamical properties of the flare. The time development
of the morphology of the flare, as revealed by the soft X-ray images
and the Hα spectroheliograms, and the physical quantities inferred
from the X-ray spectra, are compared with chromospheric evaporation
models. There is an enhancement of blueshifted emission that is closely
correlated with the hard X-ray bursts. Heating of one loop in the flare
is consistent with a conduction-evaporation model, but heating is found
in several structures that do not appear to be physically associated
with each other. No standard evaporation model can adequately explain
all of the observations.
Title: Yohkoh observations of plasma upflows during solar flares
Authors: Culhane, J. L.; Phillips, A. T.; Pike, C. D.; Fludra, A.;
Bentley, R. D.; Bromage, B.; Doschek, G. A.; Hiei, E.; Inda, M.;
Mariska, J. T.; Phillips, K. J. H.; Sterling, A. C.; Watanabe, T.
Bibcode: 1993AdSpR..13i.303C
Altcode: 1993AdSpR..13..303C
Observations of two flares, an M 2.2 event on 16 December, 1991 and the
precursor to an X1 flare on 15 November, 1991 are presented. Spectra
obtained with the Bragg Crystal Spectrometer (BCS) are compared with
data from the Hard and Soft X-ray Telescopes (HXT, SXT) and the Wide
Band Spectrometer (WBS) on the satellite. For both events the creation
of upflowing plasma is detected. While the first event seems to conform
well to the chromospheric evaporation model for high temperature plasma
production, the behaviour for the second event is more complex.
Title: Determination of coronal abundances of sulphur, calcium and
iron using the yohkoh bragg crystal spectrometer
Authors: Fludra, A.; Culhane, J. L.; Bentley, R. D.; Doschek, G. A.;
Hiei, E.; Phillips, K. J. H.; Sterling, A.; Watanabe, T.
Bibcode: 1993AdSpR..13i.395F
Altcode: 1993AdSpR..13..395F
Using spectra from the Bragg Crystal Spectrometer on Yohkoh we have
derived coronal abundances of sulphur, calcium and iron during several
flares from the ratio of the flux in the resonance line to the nearby
continuum. Multi-thermal effects have been taken into account using
differential emission measure analysis. We have also determined the
abundance of S in cool active regions during a period of very low solar
activity. We compare the coronal abundances of S, Ca and Fe with their
photospheric values.
Title: Obituary - Suemoto, Zenzaburo 1920-1991
Authors: Hiei, E.; Uchida, Y.
Bibcode: 1993SoPh..146..203H
Altcode:
No abstract at ADS
Title: In memoriam
Authors: Suemoto, Zenzaburo; Hiei, E.; Uchida, Y.
Bibcode: 1993SoPh..146..203S
Altcode:
No abstract at ADS
Title: Solar Flare Telescope project.
Authors: Ichimoto, K.; Sakurai, T.; Hiei, E.; Nishino, Y.; Shinoda, K.;
Noguchi, M.; Imai, H.; Irie, M.; Miyashita, M.; Tanaka, N.; Kumagai,
K.; Sano, I.; Suematsu, Y.; Okamoto, T.; Miyazaki, H.; Fukushima,
H.; Yose, Y.; Zhao, Z. W.
Bibcode: 1993RNAOJ...1..375I
Altcode: 1993RNOAJ...1..375I
The Solar Flare Telescope was built at Mitaka in 1989. This instrument
comprises four telescopes which observe (1) Hα images, (2) continuum
images, (3) vector magnetic fields, and (4) Doppler velocities,
respectively. The instrument aims at the study of energy build-up
and energy release in solar flares, in cooperation with the Solar-A
satellite (Yohkoh). The Solar Flare Telescope has been in operation
since 1990 December.
Title: Magnetic Field Observation with the Solar Flare Telescope
Authors: Ichimoto, K.; Sakurai, T.; Nishino, Y.; Shinoda, K.; Noguchi,
M.; Kumagai, K.; Imai, H.; Irie, M.; Miyashita, M.; Tanaka, N.; Sano,
I.; Suematsu, Y.; Hiei, E.
Bibcode: 1993ASPC...46..166I
Altcode: 1993IAUCo.141..166I; 1993mvfs.conf..166I
No abstract at ADS
Title: Determination of element abundances using the Yohkoh Bragg
Crystal Spectrometer.
Authors: Fludra, A.; Culhane, J. L.; Bentley, R. D.; Doschek, G. A.;
Hiei, E.; Phillips, K. J. H.; Sterling, A.; Watanabe, T.
Bibcode: 1993uxrs.conf..542F
Altcode: 1993uxsa.conf..542F
No abstract at ADS
Title: Helium-Like Sulphur Emission Lines in Solar Active Regions
and Their Sub-C Class Variability
Authors: Watanabe, Tetsuya; Hiei, Eijiro; Lang, James; Culhane,
J. Leonard; Bentley, Robert D.; Doschek, George A.; Bromage, Barbara
J. I.; Brown, Charles M.; Feldman, Uri; Fludra, Andrzej; Kato, Takako;
Payne, Jeffrey
Bibcode: 1992PASJ...44L.141W
Altcode:
Helium-like sulphur spectra (formation temperature, T_m ~ 18times
10(6) K) from coronal active regions are being obtained by the Bragg
Crystal Spectrometer onboard the Yohkoh mission. The average electron
temperatures of the quiescent active regions deduced from the full-disk
integrated sulphur spectra are 3.5--4 times 10(6) K. The temporal
behavior of the emission lines in the sub-C level events shows that
hot plasmas (T > 10(7) K) can be produced in these weak events.
Title: The Structure of the Coronal Soft X-Ray Source Associated
with the Dark Filament Disappearance of 1991 September 28 Using the
YOHKOH Soft X-Ray Telescope
Authors: McAllister, Alan; Uchida, Yutaka; Tsuneta, Saku; Strong,
Keith T.; Acton, Loren W.; Hiei, Eijiro; Bruner, Marilyn E.; Watanabe,
Takashi; Shibata, Kazunari
Bibcode: 1992PASJ...44L.205M
Altcode:
The internal structure of an X-ray emitting elongated object
appearing in association with Hα -dark filament disappearance of 1991
September 28 was analyzed with the help of a fine-structure enhancing
technique. We present a description of the soft X-ray structures and
their evolution, while focusing on the central, brightest part of the
structure, which is also the most difficult to resolve. We start with
the idea of applying the standard ``eruption-reconnection'' models
of Hα double-ribbon flares with filament disappearences in order to
explain this event as the appearence of an arcade of loops across the
initial dark filament position, with a row of hot spots at reconnection
sites along the loop tops. Our study of the Yohkoh Soft X-ray images,
including their fine-structure enhancement, the making of an accurately
aligned movie, and a preliminary comparison with Hα data, however,
has led us to question the applicability of these models to this type
of event. It seems, rather, that much of the bright structure comprises
heated pre-existing loops, which interact where they cross each other
in a complex ``knot'' at the northern end of the disappearing dark
filament. The bright part turns out to comprise highly sheared loops,
perhaps being pushed up by the slowly rising axial field of the dark
filament, which is, however, contained under the arcade, rather than
having broken through it. We conclude that there is a strong possibility
that much of the dark filament mass remains in the heated unwinding
axial field and briefly discuss the theoretical implications.
Title: Observations of Several Small Flares with the Bragg Crystal
Spectrometer on YOHKOH
Authors: Culhane, J. Leonard; Fludra, Andrzej; Bentley, Robert D.;
Doschek, George A.; Watanabe, Tetsuya; Hiei, Eijiro; Lang, James;
Carter, Martin K.; Mariska, John T.; Phillips, Andrew T.; Phillips,
Kenneth J. H.; Pike, C. David; Sterling, Alphonse C.
Bibcode: 1992PASJ...44L.101C
Altcode:
We have analysed data from two flares of GOES class C7.1 and C8.5
observed by the Yohkoh Bragg Crystal Spectrometer. The high sensitivity
of the Yohkoh instrument allows us to observe the very early stages of
flare development and to study small events with a high signal-to-noise
ratio. Spectral fitting programs have been used to derive plasma
temperatures, emission measures and velocities from spectra of S XV,
Ca XIX and Fe XXV. Large plasma motions indicative of chromospheric
evaporation have been found. A more detailed analysis of a flare which
occurred on 1991 October 30 is presented.
Title: The Status of YOHKOH in Orbit: an Introduction to the Initial
Scientific Results
Authors: Ogawara, Yoshiaki; Acton, Loren W.; Bentley, Robert D.;
Bruner, Marilyn E.; Culhane, J. Leonard; Hiei, Eijiro; Hirayama,
Tadashi; Hudson, Hugh S.; Kosugi, Takeo; Lemen, James R.; Strong, Keith
T.; Tsuneta, Saku; Uchida, Yutaka; Watanabe, Tetsuya; Yoshimori, Masato
Bibcode: 1992PASJ...44L..41O
Altcode:
In this introductory article accompanying the initial scientific
papers from the Yohkoh mission, we briefly summarize the design
and in-orbit function of the spacecraft and its four scientific
instruments. Although these initial results include mainly studies
based upon individual Yohkoh experiments at this early stage, there
are also analyses of combined data sets provided by several on-board
and ground-based instruments in progress. The results presented here,
and anticipated future results, suggest that the Yohkoh observations
with their comprehensive coverage of solar high-energy phenomena will
come to represent a significant milestone in the progress of solar
physics. This will be true not only regarding flares, but also for
fainter coronal structures and even coronal holes.
Title: The YOHKOH mission for high-energy solar physics
Authors: Acton, L.; Tsuneta, S.; Ogawara, Y.; Bentley, R.; Bruner, M.;
Canfield, R.; Culhane, L.; Doschek, G.; Hiei, E.; Hirayama, T. Hudson,
H.; Kosugi, T.; Lang, J.; Lemen, J.; Nishimura, J.; Makishima, K.;
Uchida, Y.; Watanabe, T.
Bibcode: 1992Sci...258..618A
Altcode: 1992Sci...258..591A
Data on solar flare mechanisms and the sun's corona will be generated
by Japan's Yohkoh satellite's X-ray imaging sensors and X-ray and
gamma-ray spectrometers. It is noted that the X-ray corona above active
regions expands, in some cases almost continually, in contradiction of
the widely accepted model of magnetohydrostatic equilibrium in such
regions. Flaring X-ray bright points have been discovered to often
involve ejecta into an adjacent, much larger and fainter magnetic loop,
which brightens along its length at speeds up to 1000 km/sec.
Title: YOHKOH Bragg Crystal Spectrometer Observations of the Dynamics
and Temperature Behavior of a Soft X-Ray Flare
Authors: Doschek, George A.; Mariska, John T.; Watanabe, Tetsuya;
Hiei, Eijiro; Lang, James; Culhane, J. Leonard; Bentley, Robert D.;
Brown, Charles M.; Feldman, Uri; Phillips, Andrew T.; Phillips,
Kenneth J. H.; Sterling, Alphonse C.
Bibcode: 1992PASJ...44L..95D
Altcode:
We describe X-ray spectra of an M1.5 flare that occurred on 1991
November 9, starting at about 0313 UT. This flare is unusual in that
very intense blueshifted components are observed in the resonance
lines of Fe XXV, Ca XIX, and S XV. During the onset of the flare,
the resonance lines of Ca XIX and Fe XXV are primarily due to
this blueshifted component, which from the Doppler effect indicates
line-of-sight speeds and turbulent motions that in combination extend
up to 800 km s(-1) .
Title: The Performance of the YOHKOH Bragg Crystal Spectrometer
Authors: Lang, James; Bentley, Robert D.; Brown, Charles M.; Culhane,
J. Leonard; Doschek, George A.; Watanabe, Tetsuya; Hiei, Eijiro;
Deslattes, Richard D.; Fludra, Andrzej; Guttridge, Philip R.; Magraw,
John E.; Payne, Jeffrey; Pike, C. David; Trow, Matthew W.
Bibcode: 1992PASJ...44L..55L
Altcode:
An overview of the Yohkoh Bragg Crystal Spectrometer is given,
complemented by details of the laboratory testing prior to launch. The
in-orbit performance of the instrument is described.
Title: Spectral analysis of a white-light flare
Authors: Sotirovski, P.; Boyer, R.; Hiei, E.; Vince, I.
Bibcode: 1992A&A...262..597S
Altcode:
A flare phenomenon was observed on 26 September 1963 at the Crimean
Astrophysical Observatory. Using an echelle spectrograph the flare
spectra from 3500 to 6700 were obtained with a dispersion of 0.56
to 0.30 A/mm. The flare lasted from 06:38 UT to 09:24 UT, with the
maximum at 07:21 UT and located N 15, W 75. Twenty spectra were
recorded during the flare. Our analysis concerns only seven time
sequences which were chosen according to the quality of the spectra;
among them four belong to the earlier phase. The line profiles and the
halfwidths of the Balmer series from H-alpha to H(14) were measured in
order to obtain electron density by using Stark broadening, and the
continuum intensity as a function of wavelength is studied in order
to deduce the emission mechanism.
Title: Yohkoh BCS Observations of Doppler Shifts Early in Solar Flares
Authors: Mariska, J. T.; Doschek, G. A.; Sterling, A. C.; Culhane,
J. L.; Hiei, E.; Watanabe, T.; Lang, J.
Bibcode: 1992AAS...180.2308M
Altcode: 1992BAAS...24..761M
No abstract at ADS
Title: The X10 Flare of 1991 June 9: White Light, H-alpha, Magnetic
Fields, and Electric Currents
Authors: de La Beaujardiere, J. -F.; Canfield, R. C.; Metcalf, T. R.;
Hiei, E.; Sakurai, T.; Ichimoto, K.
Bibcode: 1992AAS...180.4108D
Altcode: 1992BAAS...24..795D
We present observations by several instruments of the white-light
flare (WLF) of 1991 June 9 01:34 UT. A white-light image from the
National Astronomical Observatory of Japan indicates the location
of the WLF within the active region (NOAA 6659). Stokes polarimetry
from Mees Solar Observatory (University of Hawai`i) yields a vector
magnetogram and a map of the vertical electric currents. Also from
Mees comes Hα imaging spectroscopy, which is an indicator of such
specific chromospheric processes as nonthermal electron precipitation,
high coronal pressure, and mass motion. Both Mees instruments provide
continuum images, allowing coregistration of the various datasets. The
white-light emission arises from an extended area including both
sunspot umbra and penumbra. The active region magnetic field is strongly
nonpotential and has numerous vertical electric current channels. The
WLF is situated in an area of relatively low current density at the
edge of the strongest current in the active region, and the nearby
magnetic neutral line is highly sheared. The WLF site shows electron
precipitation, but only in its penumbral portion; stronger magnetic
mirroring in the umbra may inhibit precipitation there. Also, the
precipitation is not especially strong (relative to that observed
elsewhere in this flare), suggesting that the electron-beam model
for WLFs is not appropriate in this case. Also, the lack of strong
redshifts argues against a dynamical energy transport model.
Title: Time Variation of Solar Flare Temperatures Determined from
YOHKOH BCS Spectra
Authors: Sterling, A. C.; Doschek, G. A.; Mariska, J. T.; Pike, C. D.;
Culhane, J. L.; Hiei, E.; Watanabe, T.; YOHKOH BCS Team
Bibcode: 1992AAS...180.3001S
Altcode: 1992BAAS...24..775S
Bragg Crystal Spectrometer (BCS) X-ray spectra analysis from past
satellite missions indicate that it is possible to estimate temperatures
in highly ionized flare plasmas to within about 12\ resonance lines
in different He-like ions. This procedure is particularly valuable
in cases where other temperature measuring methods are insufficient,
such as during the rise phase of flares with strong X-ray spectra
blue shifts. Here we examine this ratio variation in several flares
using data from the Fe XXV, Ca XIX, and S XV channels of the BCS
experiment onboard the Yohkoh satellite. We select flares for
which we have good rise phase data, and calibrate the ratios using
dielectronic-to-resonance line ratios in selected Fe XXV spectra
assuming constant elemental abundances in each event. The Yohkoh BCS is
about an order of magnitude more sensitive than previous X-ray flare
spectrometers, and is therefore able to examine the early stages of
flare development in greater detail than previously possible. For this
study we select events for which we have good rise phase data, but data
well into the decay phase is available for a number of the selected
events. This allows us, for the first time, to follow the evolution
of flare spectra from relatively cool temperatures (~ 12 MK in Fe XXV)
to previously quoted ``typical" flare temperatures (~ 17 MK in Fe XXV).
Title: White-Light Flares of 1991 June in the NOAA Region 6659
Authors: Sakurai, Takashi; Ichimoto, Kiyoshi; Hiei, Eijiro; Irie,
Makoto; Kumagai, Kazuyoshi; Miyashita, Masakuni; Nishino, Yohei;
Yamaguchi, Kisuke; Fang, Geng; Kambry, Maspul Aini; Zhao, Zhaowang;
Shinoda, Kazuya
Bibcode: 1992PASJ...44L...7S
Altcode:
We report on observations of flare activities in an active region NOAA
6659, which appeared on the sun in 1991 June. Among six X-class flares
in this region, we observed three flares (June 4, 9, and 11), all of
which were white-light flares. A detailed discussion is given concerning
a particularly interesting white-light flare which occurred on June 11.
Title: White-Light Flare Observed at the Solar Limb
Authors: Hiei, Eijiro; Nakagomi, Yoshiteru; Takuma, Hitoshi
Bibcode: 1992PASJ...44...55H
Altcode:
A white-light flare occurring at the solar limb and its associated
loop prominence system were observed in white light on 1989 August
16. Nine photographs of these phenomena were reduced. The brightening
of the flare at the limb was explained by an increase in temperature,
estimated to be of the order of 5250 K; its total energy emitted in
the WLF was inferred to be 10(30) erg. The bright top of the flare
loop is thought to be due to bound-free/free-free emission, and its
electron density was estimated to be about 10(12--13) cm(-3) .
Title: CA {II} K Line Diagnostics of the Dynamics of the Solar
Flare Atmosphere
Authors: Fang, Cheng; Hiei, Eijiro; Yin, Su-Ying; Gan, Wei-Qun
Bibcode: 1992PASJ...44...63F
Altcode:
Observations of the Ca II K line profiles for 12 solar flares have
been analyzed and some characteristics of the red asymmetry of the
Ca II K line are given. Based on Non-LTE calculations, the influence
of velocity fields in the lower atmosphere of flares on the profiles
of the Hα and Ca II K lines has been explored. The result indicates
that a downward motion of plasma above the temperature minimum region
(TMR) as well as a contracting motion of the plasma toward TMR can
well explain the red asymmetry observed at the K_1 positions. The
typical velocity is 10--30 km s(-1) .
Title: Katsuo Tanaka (1943 - 1990).
Authors: Hiei, E.; Sakurai, T.
Bibcode: 1991SoPh..136.....H
Altcode:
No abstract at ADS
Title: The Bragg Crystal Spectrometer for SOLAR-A
Authors: Culhane, J. L.; Hiei, E.; Doschek, G. A.; Cruise, A. M.;
Ogawara, Y.; Uchida, Y.; Bentley, R. D.; Brown, C. M.; Lang, J.;
Watanabe, T.; Bowles, J. A.; Deslattes, R. D.; Feldman, U.; Fludra,
A.; Guttridge, P.; Henins, A.; Lapington, J.; Magraw, J.; Mariska,
J. T.; Payne, J.; Phillips, K. J. H.; Sheather, P.; Slater, K.;
Tanaka, K.; Towndrow, E.; Trow, M. W.; Yamaguchi, A.
Bibcode: 1991SoPh..136...89C
Altcode:
The Bragg Crystal Spectrometer (BCS) is one of the instruments which
makes up the scientific payload of the SOLAR-A mission. The spectrometer
employs four bent germanium crystals, views the whole Sun and observes
the resonance line complexes of H-like FeXXVI and He-like FeXXV,
CaXIX, and SXV in four narrow wavelength ranges with a resolving power
(λ/Δλ) of between 3000 and 6000. The spectrometer has approaching
ten times better sensitivity than that of previous instruments thus
permitting a time resolution of better than 1 s to be achieved. The
principal aim is the measurement of the properties of the 10 to 50
million K plasma created in solar flares with special emphasis on the
heating and dynamics of the plasma during the impulsive phase. This
paper summarizes the scientific objectives of the BCS and describes
the design, characteristics, and performance of the spectrometers.
Title: Solar cycle variation of coronal intensity.
Authors: Hiei, E.
Bibcode: 1991BSolD..11...86H
Altcode:
No abstract at ADS
Title: Obituary
Authors: Hiei, E.; Sakurai, T.
Bibcode: 1991SoPh..136D...4H
Altcode:
No abstract at ADS
Title: Ca ii K line asymmetries in two well-observed solar flares
of October 18, 1990
Authors: Fang, C.; Hiei, E.; Okamoto, T.
Bibcode: 1991SoPh..135...89F
Altcode:
Two-dimensional evolutions of two flares of October 18, 1990 have been
well observed in the CaII K line with a CCD camera at Norikura station
of National Astronomical Observatory in Japan. There are two common
characteristics for the flares: 3 ∼- 5 min before the impulsive phase,
the heating already begins at the footpoints of the flares, but no
asymmetry in line emission has been detected. After the onset of the
impulsive phase, CaII K line emission at the footpoints shows strong
red asymmetry, with the maximum asymmetry occurring at the same time as
the peak of the radio bursts. The maximum downward velocity is about
30 ∼ 50 km s−1. For flare 1, blue and red asymmetries
were observed in two sides of the footpoint area. They developed and
attained a maximum nearly at the same time and the inferred Doppler
velocities are comparable (30 ∼ 40 km s−1). This implies
that two mass jets started from a small region and ejected along a
loop but in opposite directions with roughly equivalent momentum. A
possible mechanism has been discussed.
Title: Solar Meriodional Motions Derived from Sunspot Observations
Authors: Kambry, M. A.; Nishikawa, J.; Sakurai, T.; Ichimoto, K.;
Hiei, E.
Bibcode: 1991SoPh..132...41K
Altcode:
Sunspot drawings obtained at the National Astronomical Observatory of
Japan during the years 1954-1986 were used to determine meridional
motions of the Sun. A meridional flow of a few ms−1
was found, which is equatorward in the latitude range from -20°
to +15° and is poleward at higher latitudes in both hemispheres. A
northward flow of 0.01° day−1 or 1.4 ms−1
at mid-latitudes (between 10° and 20°) was also detected. From our
limited data-set of three solar cycles, an indication of solar-cycle
dependence of meridional motions was found.
Title: HeI 10830 Å Observations of Active Regions
Authors: Hiei, E.; Ichimoto, K.; Fang, G.
Bibcode: 1991LNP...387...67H
Altcode: 1991fpsa.conf...67H
A number of HeI 10830Å spectroheliograms were obtained with a 25-cm
aperture coronagraph at the Norikura Solar Observatory. From these
data we found; 1) a close relationship between the steady features
in HeI 108301Å intensity, velocity fields, and the magnetic fields,
2) darkenings of points in active regions with a time scale of 10-20
minutes, and 3) various manifestations of flares in HeI 10830Å . The
HeI 10830 Å line will give us sensitive diagnostics of chromospheric
and coronal active phenomena.
Title: The SOLAR-A Bragg Crystal Spectrometer (Extended Abstract)
Authors: Culhane, J. L.; Hiei, E.; Bentley, R. D.; Brown, C. M.;
Doschek, G. A.; Feldman, U.; Lang, J.; Watanabe, T.
Bibcode: 1991LNP...387...22C
Altcode: 1991fpsa.conf...22C
No abstract at ADS
Title: Emission lines in the spectra of the 3B flare of September
19, 1979
Authors: Fang, Cheng; Okamoto, Tomizo; Hiei, Eijiro
Bibcode: 1991PNAOJ...2..173F
Altcode:
Attention is given to the spectra of a 3B flare of September 19, 1979,
in the wavelength region from 3590 to 3990 A, observed at the 25 cm
coronagraph of the Norikura Solar Observatory. Many emission lines as
well as continuum emission appeared in the spectra. An atlas of the
excess spectrum at the maximum phase of the flare, which was derived
by subtracting the nearby spectrum of the undisturbed penumbra, was
given in the absolute scale of intensity. A complete list of flare
emission lines, including the absolute intensity at the center of each
line, is also given. The total number of the emission lines is 331. An
atlas of the excess spectrum near the maximum phase of the flare in
the wavelength region from 3590 to 3990 is provided.
Title: Flare Physics in Solar Activity Maximum 22
Authors: Uchida, Yutaka; Canfield, Richard C.; Watanabe, Tetsuya;
Hiei, Eijiro
Bibcode: 1991LNP...387.....U
Altcode: 1991fpsa.conf.....U
No abstract at ADS
Title: Solar Flare Telescope and 10-cm New Coronagraph
Authors: Ichimoto, K.; Sakurai, T.; Yamaguchi, A.; Kumagai, K.;
Nishino, Y.; Suematsu, Y.; Hiei, E.; Hirayama, T.
Bibcode: 1991LNP...387..320I
Altcode: 1991fpsa.conf..320I
Two new telescopes were built at the National Astronomical
Observatory of Japan, i.e. the Solar Flare Telescope and the 10-cm New
Coronagraph. The Solar Flare Telescope was constructed at Mitaka to make
observations of photospheric velocity fields, vector magnetic fields,
and H and continuum images of active regions simultaneously. The whole
system will be completed in 1991. The 10-cm new coronagraph, which
was developed to make precise measurements of the coronal intensity in
several wavelengths, has already been in operation for one year at the
Norikura Solar Observatory. At present the accuracy of about 10-6 of
the solar disk intensity is achieved in continuum light, but further
improvement in the photometric accuracy remains to be done.
Title: The solar activity-oriented Japanese programme
Authors: Hiei, E.
Bibcode: 1991AdSpR..11d..51H
Altcode: 1991AdSpR..11...51H
There are two activity-oriented programmes in Japan; i) space
programme, and ii) the programme of ground-based optical and radio
observations. The space programme is carried out with Solar-A satellite,
which will be launched in August/September 1991, and four instruments
such as Hard X-ray Telescope (HXT), Soft X-ray Telescope (SXT), Bragg
Crystal Spectrometer (BCS), and Wide-Band Spectrometer (WBS) are on
board Solar-A satellite. A flare telescope is newly set up at Mitaka in
order to observe magnetic field, velocity field, Hα features, and white
light images in a flaring region. A radio heliograph is constructing at
Nobeyama in order to observe flares at 17GHz with a spatial resolution
of 7.3 arc sec × 16.5 arc sec and a time resolution of 50 ms.
Title: Plasma diagnostics with the Solar-A Bragg Crystal Spectrometer
Authors: Culhane, J. L.; Hiei, E.; Bentley, R. D.; Brown, C. M.;
Doschek, G. A.; Feldman, U.; Lang, J.; Watanabe, T.
Bibcode: 1991AdSpR..11e..77C
Altcode: 1991AdSpR..11...77C
A Bragg Crystal spectrometer is one of the instruments on the Solar-A
mission. Using bent crystals, the spectrometer will observe the
resonance line complexes of the H-like Fe XXVI, and He-like Fe XXV
and Ca XIX ions with a sensitivity 5 to 10 times that of the SMM Bent
Crystal Spectrometer. It will also study the lower temperature lines
of He-like S XV. The improved sensitivity will allow observations
much earlier in the impulsive phase of flares than has previously been
possible. The new observations should help to answer questions about
plasma heating and dynamics. As well as providing information on line
profiles and shifts, the selected spectral lines will also provide
electron temperature and emission measure estimates over a range from
5 to 50 MK. The onboard microprocessor will permit spectral resolution
to be traded against time resolution during an observation.
Title: Continuous and Line Spectra of Granules and Intergranular Lanes
Authors: Suemoto, Z.; Hiei, E.; Nakagomi, Y.
Bibcode: 1990SoPh..127...11S
Altcode:
Temperature and velocity structures above granules and intergranular
lanes were studied on spectrograms covering CaII H and K lines. In
agreement with our earlier results, it was confirmed more quantitatively
that there appear two kinds of bright continua, one in the outer wings
(granular continuum) and the other in the inner wings (temporarily
called K0-continuum) of CaII H and K lines, and that these two
kinds of bright continua are located more or less in a complementary
fashion. Further, it was found that the bright K0-continuum is well
associated with higher central residual intensity of absorption
lines. These facts suggest that in the upper photosphere of, say,
τ < 0.1, there are high temperature regions in the intergranular
lanes. Motions above granular regions are essentially upwards, whereas
those of intergranular regions are predominantly downwards, and in
the uppermost photosphere the motions become more random.
Title: A large and complex flare on 3 February 1982.
Authors: Mizugaki, Kazuo; Nitta, Nariaki; Hiei, Eijiro
Bibcode: 1990PNAOJ...1..297M
Altcode:
The authors present an Hα morphological study of a well-developed
2B flare that occurred on 3 Feb 1982. The flare, associated
with a long-enduring hard X-ray burst, has some interesting Hα
characteristics.
Title: Sudden disappearance of dark filaments of the sun.
Authors: Yamaguchi, K.; Hiei, E.
Bibcode: 1990RNAOJ...1....1Y
Altcode: 1990RNOAJ...1....1Y
There are two types of sudden disappearance: one is due to a heating
up phenomenon and the other due to a dynamic one. In this report sudden
disappearance is statistically studied.
Title: The observation of total solar eclipse in Indonesia on 11
June 1983.
Authors: Shimizu, Y.; Miyazaki, H.; Imai, H.; Hiei, E.
Bibcode: 1990RNAOJ...1...29S
Altcode: 1990RNOAJ...1...29S
The total solar eclipse on 11 June 1983 was observed at Cepu, Central
Java. The planning, observing instruments, setting-up and the observing
procedure are described. Electron number density in thread-like fine
structures in an active region of the corona was derived to be about
5×109 from the corona taken at the eclipse.
Title: CCD data acquisition system installed on the spectrograph at
the Norikura Solar Observatory.
Authors: Hamana, S.; Kumagai, K.; Ichimoto, K.; Sakurai, T.; Hiei, E.
Bibcode: 1990RNAOJ...1...13H
Altcode: 1990RNOAJ...1...13H
A new data acquisition system is installed on the 25-cm coudé-type
coronagraph at the Norikura Solar Observatory. Three CCD cameras (2/3
inch, 512×480 pixels) are mounted on the spectrograph; one at the short
focal length exit window and the other two at the long focal length exit
window. Fields of view along the entrance slit of the spectrograph are
9'15″ 2'22″and 3'00″ respectively. Spectral images are digitized
and integrated on the image processing unit. The new system has made
possible (1) the observations in the near-infrared wavelength, (2)
high accuracy in data compared to photographic observations, and (3)
the analyses of large amounts of spectral data.
Title: Bright Features in the Intergranular Region
Authors: Suemoto, Z.; Hiei, E.
Bibcode: 1990IAUS..138...97S
Altcode:
No abstract at ADS
Title: Phase Relation between Velocities and Temperature Fluctuations
of the Solar 5-Minute Oscillation
Authors: Ichimoto, K.; Hamana, S.; Kumagai, K.; Sakurai, T.; Hiei, E.
Bibcode: 1990LNP...367..205I
Altcode: 1990psss.conf..205I
Phase relations between the velocities and temperature oscillations in
the solar photosphere are investigated on the - diagram. Distributions
of the phase differences on the - plane are roughly reproduced
by a simple analytical model, but the detailed fitting is not
satisfactory. In the 5-minute band, temperature reaches its peak when
the atmosphere is moving downward. The amount of the phase difference
between temperature and velocity suggests the radiative damping time
of 1-40 s. Identification of the g-mode oscillation is not clear.
Title: Flare Energy Release and Deposition
Authors: Holman, G.; Benka, S.; de La Beaujardiere, J.; Dulk, G.;
Gabriel, A.; Henoux, J. C.; Hiei, E.; Kane, S.; Klein, L.; Kuin, P.;
Larosa, T.; MacKinnon, A.; McClements, K.; Moses, D.; Ramaty, R.;
Tromans, N.; Vilmer, N.
Bibcode: 1989tnti.conf....3H
Altcode:
No abstract at ADS
Title: Spectral manifestations of the granular velocity field near
the solar limb
Authors: Ichimoto, Kiyoshi; Hiei, Eijiro; Nakagomi, Yoshiteru
Bibcode: 1989PASJ...41..333I
Altcode:
It is found that high-resolution spectra taken near the solar limb show
very different wiggly line patterns of photospheric lines compared
with those taken near the disk center. (1) The absorption line look
like twisted threads. As the line of sight moves towards the limb,
the lines first show a gradual redshift and then it is followed by a
quick change to a blueshift. (2) The velocity distribution measured
in the line core is displaced toward the limb relative to that in the
line wing. These characteristics are well reproduced by an atmospheric
model with a two-dimensional grandular velocity field. It is shown that
the horizontal component of the grandular velocity plays an important
role for producing a line wiggle near the solar limb.
Title: SYSTEMATIC OBSERVATIONS OF THE SUN (In honour of Helen Dodson
Prince): Future work
Authors: Livingston, W.; Zwaan, K.; Hiei, E.; Paterno, L.
Bibcode: 1989HiA.....8..677L
Altcode:
No abstract at ADS
Title: Structure of the Solar Corona
Authors: Sakurai, T.; Hiei, E.
Bibcode: 1989HiA.....8..513S
Altcode:
No abstract at ADS
Title: Active phenomena of the sun in February 1986
Authors: Hiei, E.; Yamaguchi, K.
Bibcode: 1989NURIA..36...17H
Altcode:
Optical phenomena of solar activity in February 1986 are
summarized. There appeared three active regions, NOAA AR4711, 4712,
and 4713, and AR4711 and 4713 produced large flares.
Title: The Bragg Crystal Spectrometer Experiment on SOLAR-A
Authors: Hiei, E.; Culhane, J. L.; Doschek, G. A.
Bibcode: 1988BAAS...20..710H
Altcode:
No abstract at ADS
Title: TV monitor for the observation of solar phenomena.
Authors: Fukushima, H.; Shimizu, Y.; Hiei, E.
Bibcode: 1988TokRe..21..167F
Altcode:
No abstract at ADS
Title: Coronal structure in the green line over three solar cycles.
Authors: Hiei, Eijiro; Okamoto, Tomizo
Bibcode: 1988sscd.conf..353H
Altcode:
Latitude distribution of the intensity of the green coronal line
for the period from 1951 to 1987 was studied. The iso-contour curves
of the latitude distribution versus time are almost similar to the
butterfly diagram of the sunspots. There appears another intensity
peak at a higher latitude. The peak shows a drift, on the average,
toward to the equator with time, but it also shows a poleward drift,
which is associated with the prominences.
Title: Bright threads in the inner wing of solar Ca II H and K lines.
Authors: Suemoto, Zenzaburo; Hiei, Eijiro; Nakagomi, Yoshiteru
Bibcode: 1988sscd.conf..282S
Altcode:
On spectrograms of the H and K lines at quiet regions of the Sun,
bright threads visible in the real continuum due to the granulations
are also seen in the outer wings as far as |Δλ| ≡ 3 A from the
K line centre. At the inner wings (3 A ⪆ |Δλ| ⪆ 0.5 A in the K
line) bright threads are also seen, but their spatial distribution is
different from the former ones. The threads at the inner wings appear
at the intergranular regions, and many of them are seen inside the
supergranulation. These facts reflect that the granular high temperature
layer stops penetrating at a certain height in the photosphere, and
that the intergranular bright threads at the inner wings are due to a
hotter temperature layer, located at a considerably higher photospheric
layer than the granulation.
Title: Passage of the Venus and the Mercury behind the Sun.
Authors: Hiei, Eijiro; Soma, Mitsuru; Fukushima, Hideo
Bibcode: 1988sscd.conf..267H
Altcode:
The occultation of the Venus and the Mercury by the Sun is a good
opportunity for measuring light-deflection in the gravitational field
of the Sun. The planets move closer and closer to the Sun with time,
and many positions of the planets from the Sun, compared with those
of stars observed during a total solar eclipse, can be measured. The
accuracy in the determination of the light-deflection, therefore, would
be higher in the planet's occultation than in a total solar eclipse.
Title: Bright threads in the inner wing of solar Ca II K line
Authors: Suemoto, Z.; Hiei, E.; Nakagomi, Y.
Bibcode: 1987SoPh..112...59S
Altcode:
On spectrograms of the K line at quiet regions of the Sun, bright
threads visible in the real continuum due to the granulations are
also seen in the outer wing as far as ¦Δλ¦ ∼ 3 Å from the
line centre. At the inner wing (3 Å ≳ ¦Δλ¦ ≳ 0.5 Å)
bright threads are also seen, but their spatial distribution
is different from the former ones. The threads at the inner wing
appear at intergranular regions, and many of them are seen inside the
supergranulation. Their size and number density are about the same as
those of the granulation. These facts reflect that the penetration of
the granular high temperature layer stops at a certain height in the
photosphere, and that the intergranular bright threads at the inner
wing are due to a hotter temperature layer, located at a considerably
higher photospheric layer than the granulation.
Title: Review of optical observations of solar flares
Authors: Hiei, E.
Bibcode: 1987SoPh..113..249H
Altcode: 1982SoPh..113..249H
The recent observations of solar flares, made with a Lyot filter and
a spectrograph in Hα, HeD3, higher Balmer lines, metallic lines,
and continuum, are discussed. It is important to study the energy
supply of non thermal particle/ conduction/ irradiation into the lower
atmosphere from the optical observations with high temporal and spatial
resolutions. Simultaneous observations from ground-based observatories
and instruments on board satellites are necessary for understanding
flare plasma of low and high energy.
Title: Bright region at the polar CAP of the sun at millimeter
wavelengths
Authors: Hiei, Eijiro
Bibcode: 1987PASJ...39..937H
Altcode:
Observations of the sun were carried out at 36 and 98 GHz using a 45-m
radio telescope at the Nobeyama Radio Observatory and radio-heliograms
with angular resolutions of 46 and 17 arcsec, respectively. Attention
is given to the polar-cap brightenings in both the north and south
polar regions. A 3-7 percent brightness enhancement was observed at
36 GHz while no enhancement was observed at 98 GHz (Kosugi et al.,
1986). A model-atmosphere-based estimate of the enhancement turns out
to be too weak, while the observed enhancement cannot be explained by
existing models of the atmospheric structure of the polar region as
derived from EUV observations.
Title: Coronal structure observed at the total solar eclipse of 11
June, 1983 in Indonesia
Authors: Hiei, E.; Shimizu, Y.; Miyazaki, H.; Imai, H.; Sato, K.;
Kuji, S.; Sinambela, W.
Bibcode: 1986Ap&SS.119....9H
Altcode:
From the photographs taken at the total solar eclipse of 11 June
1983, we derived the electron density for the north polar rays and
for the thread-like fine structures above the active region, which
are 108 at 1.4 solar radii and 3×109 at 1.15
solar radii, respectively. The brightness distributions of the corona
at the polar region and above the active region, and the flattening
index were also derived.
Title: White light flares seen from the spectroscopic observations
and the direct images
Authors: Hiei, Eijiro
Bibcode: 1986AdSpR...6f.227H
Altcode: 1986AdSpR...6Q.227H
White light flares are classified into three types from the form
of the bright region and time coincidence with a hard X-ray burst:
impulsive, gradual, and diffuse types. The impulsive type shows a
good correlation between the brightness change and hard X-ray flux,
the gradual one appears in a gradual phase of a flare. The bright
region is compact in both types. The diffuse one, however, appears in
an extended area at an impulsive phase.
Title: White light flare of 24 - 25 April 1984.
Authors: Hiei, Eijiro; Zirin, Harold; Wang, Jingxiu
Bibcode: 1986lasf.conf..129H
Altcode: 1986lasf.symp..129H
White-light brightenings appeared at 4 min. after the starting time of
the Hα flare. The time correlation between white-light brightenings
and hard X-ray flux is good. The bright patches moved toward the same
direction as the Hα bright strands of the flare.
Title: White light flares and atmospheric modeling (Working Group
report).
Authors: Machado, M. E.; Avrett, E. H.; Falciani, R.; Fang, C.;
Gesztelyi, L.; Henoux, J. -C.; Hiei, E.; Neidig, D. F.; Rust, D. M.;
Sotirovski, P.; Svestka, Z.; Zirin, H.
Bibcode: 1986lasf.conf..483M
Altcode:
The authors give a short summary of their discussions, and a set
of recommendations which may help in the study of white light flare
emission processes.
Title: A SKYLAB flare associated with a hard X-ray burst
Authors: Widing, K.; Hiei, E.
Bibcode: 1984ApJ...281..426W
Altcode:
The Skylab flare of Jan. 21, 1974 has been studied as a clear example of
impulsive EUV emission associated with a hard X-ray burst. The spatial
characteristics and temporal behavior of the impulsive and gradual
phase components are described, and the emission measure distribution
in the brightest impulsive emission patch is derived and compared with
the emission measure plot of the hot gradual component. The column
emission measure of this patch shows a steep decrease between He II and
O IV and a relatively flat distribution between O IV and Fe XIV. The
impulsive behavior in the patch appears to extend in temperature only
as high as Si X and Fe XIV, consistent with the impulsive enhancement
being almost entirely confined to ions emitting at temperatures below
one or two million degrees. The emission measure of the hot kernel in
the impulsive phase spectrum is confined to temperatures greater than
1.5 million K and has steep slope between 1.5 and 8 million K.
Title: The HESP/R satellite project
Authors: Tanaka, K.; Hiei, E.
Bibcode: 1984AdSpR...4g.377T
Altcode: 1984AdSpR...4..377T
The aim of the HESP/R (High Energy Solar Physics/Radiation) satellite
project is to obtain data of γ-ray, hard X-ray soft X-ray, EUV, and
visible radiation of solar flares at the next solar maximum in order
to study physics of flares. The HESP/R will be a spinning satellite of
4-5 rotations per min., and the spin axis is off-set by a small angle
(0.5°-1.0°) from the Sun. Total weight will be 400 kg and launched
in 1991 with M-3S-II rocket by ISAS.
Title: High-temperature phenomena in flares
Authors: Takakura, T.; Tanaka, K.; Hiei, E.
Bibcode: 1984AdSpR...4g.143T
Altcode: 1984AdSpR...4..143T
High temperature phenomena occurring in solar flares are reviewed
based on hard X-ray images and spectral analyses of highly ionized
iron lines observed aboard the Hinotori spacecraft. Five basic
flare components are proposed, i.e., impulsive (I), gradual hard (GH),
thermal (T), quasi thermal (QT) and hot thermal (HT) components. A
flare shows some combination of the five components. Energy release
and transport for each component would give a lot of variety to the
hard X-ray image, spectrum and time history of X-rays.
Title: Observation of the flare of 12 June 1982 by Norikura
coronagraph and Hinotori
Authors: Hiei, E.; Okamoto, T.; Tanaka, K.
Bibcode: 1983SoPh...86..185H
Altcode:
Flare activity was observed near the limb with two coronagraphs at the
Norikura Solar Observatory and the Soft X-ray Crystal Spectrometer
(SOX) aboard HINOTORI. A prominence activation occurred and then
Hα brightenings were seen on the disk near the prominence. The
prominence became very bright and its electron density increased to
1012.8 cm−3 in 1/2 hour. Loop prominence systems
appeared above the Hα brightenings about half an hour after the onset
of the flare, and were observed in the coronal lines CaXV 5694Å,
FeXIV 5303Å, and FeX 6374Å. Shifted and asymmetric profiles of the
emission line of 5303Å were sometimes observed, and turbulent phenomena
occurred even in the thermal phase. The energy release site of the
flare at the onset would be lower than 20 000 km above the solar limb.
Title: The total solar eclipse of 11 June 1983.
Authors: Hiei, E.; Saito, S.; Kanazawa, T.; Sato, K.; Maihara, T.
Bibcode: 1983AstHe..76..268H
Altcode:
No abstract at ADS
Title: A Continuous Spectrum of a White-Light Flare
Authors: Hiei, E.
Bibcode: 1982SoPh...80..113H
Altcode:
White-light continuum was observed at the Norikura Solar Observatory
in a 2B flare of 10 September 1974 in the spectral region between
3600 Å and 4000 Å. The duration of continuum emission was 8-12
min. The continuum shows a Balmer free-bound component, but the
main contribution to the continuum between 3646 Å and 4000 Å is
H− emission. The white-light continuum, therefore, is
thought to be of photospheric origin. The energy loss in the continuum
is 1027 erg s−1.
Title: Optical and X-Ray Flare Event of 1981MAY13
Authors: Hiei, E.; Tanaka, K.; Watanabe, T.; Akita, K.
Bibcode: 1982sofl.symp..208H
Altcode:
No abstract at ADS
Title: The thermal X-ray flare plasma
Authors: Moore, R.; McKenzie, D. L.; Svestka, Z.; Widing, K. G.; Dere,
K. P.; Antiochos, S. K.; Dodson-Prince, H. W.; Hiei, E.; Krall, K. R.;
Krieger, A. S.
Bibcode: 1980sfsl.work..341M
Altcode: 1980sofl.symp..341M
Following a review of current observational and theoretical knowledge
of the approximately 10 to the 7th K plasma emitting the thermal soft
X-ray bursts accompanying every H alpha solar flare, the fundamental
physical problem of the plasma, namely the formation and evolution of
the observed X-ray arches, is examined. Extensive Skylab observations
of the thermal X-ray plasmas in two large flares, a large subflare and
several compact subflares are analyzed to determine plasma physical
properties, deduce the dominant physical processes governing the plasma
and compare large and small flare characteristics. Results indicate
the density of the thermal X-ray plasma to be higher than previously
thought (from 10 to the 10th to 10 to the 12th/cu cm for large to
small flares), cooling to occur radiatively as much as conductively,
heating to continue into the decay phase of large flares, and the
mass of the thermal X-ray plasma to be supplied primarily through
chromospheric evaporation. Implications of the results for the basic
flare mechanism are indicated.
Title: Pre-Flare Evolution and the Beginning of Flares
Authors: Hiei, E.
Bibcode: 1980jfss.conf..185H
Altcode:
No abstract at ADS
Title: A single loop of 21 January 1974 flare.
Authors: Hiei, E.; Widing, K. G.
Bibcode: 1979SoPh...61..407H
Altcode:
A single loop associated with a flare of 21 January 1974 was studied
with NRL spectroheliograms in order to understand the phenomenon of
`evaporation'. The loop seen in the emission lines of Fe XV reached
its maximum brightness 15 min after the onset. The loop is different
from a flare loop because of the time sequence in which it appeared
and is different from a post-flare loop prominence system because of
its morphology. The electron density in the loop increases gradually
to 4 × 1010 cm−3. The material of the loop is
thought to be supplied from the lower atmosphere of the chromosphere
or the photosphere. The loop is an associated phenomenon of the main
flare event distinguished by a longer rise time (15 min) and a lower
peak temperature (2 × 106 K).
Title: Preliminary report on the observations of the total solar
eclipse of 30 June 1973 in Africa.
Authors: Moriyama, F.; Hiei, E.; Tokuya, A.; Miyazaki, H.
Bibcode: 1975TokRe..17..389M
Altcode:
No abstract at ADS
Title: Microphotometer controlled by "mini-computer".
Authors: Shimizu, I.; Hirayama, T.; Ohki, Y.; Fukatsu, M.; Oe, T.;
Shimizu, Y.; Hiei, E.
Bibcode: 1975TokRe..17..329S
Altcode:
No abstract at ADS
Title: Photometric atlas of emission lines of the solar chromosphere
between 3599 Å and 4017 Å.
Authors: Hiei, E.; Fukatsu, M.
Bibcode: 1974AnTok..14...37H
Altcode: 1974AOTok..14...37H
No abstract at ADS
Title: The Chromospheric Continuum Observed at the Total Solar
Eclipse of 12 November 1966 and a Model of the Low Chromosphere
Authors: Tanaka, K.; Hiei, E.
Bibcode: 1972PASJ...24..323T
Altcode:
We have obtained the Balmer continuum and the continuum at 40O0
in the chromosphere by observing the total solar eclipse of 12
November 1966. These data are in good agreement with those of previous
eclipses. Existing chromospheric models are compared with comments. By
using this eclipse data and the continuum at 6900A observed by MAKITA
(1971) at the total solar eclipse of 7 March 1970, we have constructed a
model chromosphere, which can explain the eclipse observations and also
the observations of UV and mm radiation. In our model the distribution
of hydrogen density is equal to that of the NOYRs and KALKoFEN (1970)
model. The electron density and temperature lie between those of
the NOYRs and KALKoFEN (1970) model and of the ATHAY and CANFIELD
(1970) model, respectively. Key words: Chromospheric continuum; Model
chromosphere; Solar eclipse.
Title: Photospheric Mass Motions Associated with a Flare
Authors: Yoshimura, H.; Tanaka, K.; Skimizu, M.; Hiei, E.
Bibcode: 1971PASJ...23..443Y
Altcode:
Curved absorption lines were observed in a flare region. Curvatures
of the lines are larger in the weaker lines than in the stronger
lines, appearing large at an onset of the flare, and then gradually
diminishing. These curved lines are interpreted by large-scale
mass motions with a dimension of 1 km in the photosphere and low
chromosphere. Key words: Photosheric mass motion; Curved lines; Flare.
Title: Digital microphotometer.
Authors: Hiei, E.; Shimizu, I.; Ohki, Y.; Nishimura, S.
Bibcode: 1971TokRe..15..584H
Altcode:
No abstract at ADS
Title: Observation of the Outer Layer of the Sun at the Total Solar
Eclipse of 12 November 1966
Authors: Hiei, E.; Hirayama, T.
Bibcode: 1970PASJ...22..545H
Altcode:
The observation of the total solar eclipse of 12 November 1966
by a slitless spectrograph using the grazing incidence method is
described. About 300 spectrograms of the chromosphere and prominences
with dispersions of 1.2A/mm and 1.8A/mm were successfully obtained at a
maximum height resolution of 380 km. Because of the grazing incidence
method, the widths as well as the intensities of emission lines can
be measured. A brief description of spectrograms is given. Key words:
Solar eclipse; Flash spectra; Outer layer of the sun.
Title: Emission Gradients in the Continuum at the Sun's Limb
Authors: Hiei, Eijiro; Faller, James E.
Bibcode: 1968SoPh....3..513H
Altcode:
The intensity variation at the sun's limb has been studied in order to
derive the gradient of the temperature in the low chromosphere. Eclipse
observations show that in the continuum the height gradients of the
total intensity vary systematically with wavelength; the observed
gradient in the red is found to be steeper than in the blue. This
wavelength dependence of the gradients is explained by the temperature
increase in the low chromosphere.
Title: Continuous Spectrum in the Chromosphere
Authors: Hiei, E.
Bibcode: 1963PASJ...15..277H
Altcode:
From an analysis of continuous emissions both at 2 3626 A and at 2
4117 A taken at the solar eclipse of Oct. 12, 1958, a model of the
chromosphere below 2000 km was derived. Spicule structures observed
in many emission lines on successive exposures enable us to count the
number of spicules down to about 1500km. The analysis was made on the
continuous emissions by taking account of spicules. The scale height
of the atmosphere at the lowest chromosphere was derived to be nearly
100 km. Ionization temperature increased slowly from at 200 km to at
1000 km. The distribution of numbers of spicules with height above 3000
km may explain the observed emission gradients of the chromospheric
lines. It is suggested that the chromosphere is composed only of
spicules and the interspicular region is part of the corona.
Title: Observation of the Flash Spectrum at the Total Solar Eclipse
of October 12, 1958
Authors: Suemoto, Z.; Hiei, E.
Bibcode: 1962PASJ...14...33S
Altcode:
In 1958 eclipse in South Pacific, we observed the flash spectrum with a
slitless spectrograph, but with the grating used very obliquely. Because
of the minifying property of this method we can measure both intensity
and line profile of - chro mospheric emission lines. Dispersion
was about 2.3 A/ram. Standardization were - made hy means of tube
sensitometers for relative energies, and for absolute energies the
partial sun was used. From the appearance of spicule structures on
weaker lines it looks that the chromosphere has a sheath like spicule
structure much furtber down than is believed. Short aecounts of some
other features of our spectrograms are also given.
Title: A Model of the Coronal Condensation
Authors: Hiei, E.
Bibcode: 1962JPSJS..17B.227H
Altcode: 1962ICRC....7B.227H; 1962JPSJ...17B.227H; 1962PSJaP..17B.227H
No abstract at ADS
Title: Structure of the Flare
Authors: Suemoto, Z.; Hiei, E.; Hirayama, T.
Bibcode: 1962JPSJS..17B.231S
Altcode: 1962ICRC....7B.231S; 1962PSJaP..17B.231S; 1962JPSJ...17B.231S
No abstract at ADS
Title: Unusual Decrease of Microwave Solar Radio Emission During
Flare on November 30, 1959
Authors: Kakinuma, T.; Hiei, E.
Bibcode: 1960PASJ...12..117K
Altcode:
b usual decrease of microwave solar radio' emission on November 30, 1959
observed at the Research Institute of Atmospherics, Nagoya University
is reported, together with the optical observations of the associated
flare made at the Tokyo Astronomical Observatory.
Title: Flash Spectrum by the Grazing Incidence Method at the Total
Solar Eclipse of October 12, 1958
Authors: Suemoto, Z.; Hiei, E.
Bibcode: 1959PASJ...11..122S
Altcode:
At the total solar eclipse of October 12, 1958, in South Pacific a new
type of spectrograph was used in order to study both the intensity
distributions and the profiles of chromospheric and photospheric
lines. This spectrograph is similar to convetional slitless
spectrographa normally used for the flash spectrum, but the essential
difference is that the grating is used very obliquely. In this way we
succeeded in taking flash spectra on which the line profiles are no
more affected by the extension of the chromosphere and the atmospheric
scintillation.
Title: Balmer Series Lines of the Flare and its Structure
Authors: Suemoto, Z.; Hiei, E.
Bibcode: 1959PASJ...11..185S
Altcode:
The line widths of Balmer series lines from H to H14 were measured
on a number of spectrograms of flares of medium importance taken by
a wide range spectrograph with the dispersion of 3 A/mm. The width is
very wide for the earlier members and decreases to a minimum somewhere
around H9 and then increases slowly to higher members. By assigning the
Stark broadening to higher members and the self absorp tion to lower
members we derived the values of the electron density and total number
of hydrogen atoms in the second quantum state. On the basis of uniform
model of the flare these two values can only be made compatible when the
very small geometieal thickness of the order of 10 km is attributed to
the whole extension of the flare. We like to suggest, therefore, that
the flare is composed of unresolvably fine, presumably thread like,
condensations distributed over the whole extension.