explanation blue bibcodes open ADS page with paths to full text
Author name code: kim-kap-sung
ADS astronomy entries on 2022-09-14
=author:"Kim, Kap-Sung" OR =author:"Kim, Kap Sung"
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Title: Optimal Lunar Point Return Orbit Design and Analysis via a
Numerical Three-Step Approach
Authors: Song, Yongjun; Song, Young-Joo; Kim, Kap-Sung; Jin, Ho;
Lee, Donghun
2020IJASS..21.1129S Altcode: 2020IJASS.tmp...46S
Herein, the characteristics of the Moon-to-Earth (M-E) trajectory
satisfying the point return orbit (PRO) conditions are analyzed and
optimized. A numerical three-step approach is proposed to serve as
a useful tool to generate trajectory while preparing for real-world
missions. To formulate the given problem, each step properly adapts
different equations of motion with design parameters suitable to
each step's primary objective. Three- and N-body equations of motion
are used as a basis, and PRO is constrained by the parking orbit at
the Moon and Earth re-entry corridor associated with the re-entry
position. Consequently, the major trans-Earth-injection (TEI) maneuver
condition at the Moon is optimized together with the right ascension
of the ascending node and the argument of the latitude. Moreover, the
TEI maneuver magnitude with its execution date and required time of
flight is optimized to form PRO. Adopting this three-step approach,
the effect of the Moon's relative motion with respect to the Earth
to form the optimal TEI condition is clearly analyzed. In addition,
direct insight on the TEI condition is obtained by expressing the
M-E rotating frame, which is expected to save time and effort while
generating initial guesses for TEI conditions.
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Title: A New Method for Coronal Magnetic Field Reconstruction
Authors: Yi, Sibaek; Choe, Gwang-Son; Cho, Kyung-Suk; Kim, Kap-Sung
2017SPD....4810604Y Altcode:
A precise way of coronal magnetic field reconstruction (extrapolation)
is an indispensable tool for understanding of various solar
activities. A variety of reconstruction codes have been developed so
far and are available to researchers nowadays, but they more or less
bear this and that shortcoming. In this paper, a new efficient method
for coronal magnetic field reconstruction is presented. The method
imposes only the normal components of magnetic field and current
density at the bottom boundary to avoid the overspecification of the
reconstruction problem, and employs vector potentials to guarantee the
divergence-freeness. In our method, the normal component of current
density is imposed, not by adjusting the tangential components of
A, but by adjusting its normal component. This allows us to avoid a
possible numerical instability that on and off arises in codes using
A. In real reconstruction problems, the information for the lateral
and top boundaries is absent. The arbitrariness of the boundary
conditions imposed there as well as various preprocessing brings about
the diversity of resulting solutions. We impose the source surface
condition at the top boundary to accommodate flux imbalance, which
always shows up in magnetograms. To enhance the convergence rate, we
equip our code with a gradient-method type accelerator. Our code is
tested on two analytical force-free solutions. When the solution is
given only at the bottom boundary, our result surpasses competitors
in most figures of merits devised by Schrijver et al. (2006). We have
also applied our code to a real active region NOAA 11974, in which two
M-class flares and a halo CME took place. The EUV observation shows
a sudden appearance of an erupting loop before the first flare. Our
numerical solutions show that two entwining flux tubes exist before the
flare and their shackling is released after the CME with one of them
opened up. We suggest that the erupting loop is created by magnetic
reconnection between two entwining flux tubes and later appears in
the coronagraph as the major constituent of the observed CME.
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Title: Heating of an Erupting Prominence Associated with a Solar
Coronal Mass Ejection on 2012 January 27
Authors: Lee, Jin-Yi; Raymond, John C.; Reeves, Katharine K.; Moon,
Yong-Jae; Kim, Kap-Sung
2017ApJ...844....3L Altcode: 2017arXiv170609116L
We investigate the heating of an erupting prominence and loops
associated with a coronal mass ejection and X-class flare. The
prominence is seen as absorption in EUV at the beginning of its
eruption. Later, the prominence changes to emission, which indicates
heating of the erupting plasma. We find the densities of the erupting
prominence using the absorption properties of hydrogen and helium in
different passbands. We estimate the temperatures and densities of
the erupting prominence and loops seen as emission features using
the differential emission measure method, which uses both EUV and
X-ray observations from the Atmospheric Imaging Assembly on board
the Solar Dynamics Observatory and the X-ray Telescope on board
Hinode. We consider synthetic spectra using both photospheric and
coronal abundances in these calculations. We verify the methods for the
estimation of temperatures and densities for the erupting plasmas. Then,
we estimate the thermal, kinetic, radiative loss, thermal conduction,
and heating energies of the erupting prominence and loops. We find
that the heating of the erupting prominence and loop occurs strongly
at early times in the eruption. This event shows a writhing motion of
the erupting prominence, which may indicate a hot flux rope heated by
thermal energy release during magnetic reconnection.
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Title: Laboratory measurements of light polarization on samples
targeted for the lunar regolith
Authors: Kim, Il-Hoon; Sung, Suk Kyung; Kim, Sungsoo S.; Jeong,
Minsup; Sim, Chae Kyung; Baek, Kilho; Kim, Kap-Sung; Choi, Young-Jun
2017AdSpR..59.1629K Altcode:
We carried out multi-band (B, V, and R bands) polarimetric measurements
of several soil samples targeted for the lunar regolith (JSC-1A,
Fe<SUB>2</SUB> O<SUB>3</SUB> , SiC, and JSC-1Mars). Our laboratory
experiments are intended to provide some constraints to the theoretical
and numerical studies of the light scattering off the particulate
surface of airless bodies in the solar system. Among our samples,
the lunar soil simulant JSC-1A has the closest α<SUB>max</SUB> to
the typically observed value on the lunar surface, ∼100 ° , where
α<SUB>max</SUB> is the phase angle at which the polarization has the
maximum value. In the other samples, α<SUB>max</SUB> is higher than 120
° or significantly wavelength dependent. The empirical relationship
between the grain size, maximum polarization and albedo for the lunar
regolith overestimates the actual grain sizes of some of our samples by
a factor of up to ∼6. The measured polarization degrees and albedos
of the JSC-1A sample are similar to the typical observed values of
the lunar maria. We also find that the wavelength dependence of both
polarization degree and albedo is larger for smaller-grain samples.
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Title: Physical properties of coronal mass ejection plasma associated
with erupting prominences as seen emission or absorption features
in EUV and X-rays
Authors: Lee, Jin-Yi; Raymond, John C.; Reeves, Kathy; Moon, Yong-Jae;
Kim, Kap-Sung
2016SPD....4740201L Altcode:
We investigate the physical properties (temperature, density, mass, and
energy) of coronal mass ejection plasmas observed by the Atmospheric
Imaging Assembly on Solar Dynamics Observatory and X-ray Telescope
on Hinode. The prominences are seen as absorption features in EUV
at the beginning of their eruptions. Later the prominences change
to emission features during eruptions, which indicates the heating
of the erupting plasma. We find the temperatures and densities of the
erupting prominences using absorption properties of hydrogen and helium
in different passbands. We estimate the temperatures and densities of
the erupting plasma in emission features using differential emission
measure method, which uses both EUV and X-ray observations applying
various spectra using photospheric and coronal abundances. We verify and
discuss the methods for the estimation of temperatures and densities
for erupting plasmas. Lastly, we discuss the heating of the coronal
mass ejection plasmas.
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Title: Statistical analysis of supersonic downflows in sunspot
penumbrae.
Authors: Kim, Hyunnam; Lagg, Andreas; Solanki, Sami K.; Narayan,
Gautam; van Noort, Michiel; Kim, Kap-Sung
2015IAUGA..2254868K Altcode:
Supersonic downflow patches was found in the outer edge of sunspot
penumbra. These patches are believed to be the return channels of the
Evershed flow. There was previous study to investigate their structure
in detail using Hinode SOT/SP observations (M. van Noort et al. 2013)
but their data sample was only two sunspots. To make general description
it needs to check more sunspot data sample.We selected 242 downflow
patches of 16 sunspots using Hinode SOT/SP observations from 2006 to
2012. Height-dependent maps of atmospheric parameters of these downflows
was produced by using HeLix which was height dependent LTE inversion
code of Stokes profiles.Statistical analysis of magnetic field strength,
inclination angle of field line, temperature and line-of-sight velocity
are presented. The recovered atmospheric data tell us that downflow
patches have different physical signatures comparing normal penumbra
properties. Furthermore, our results of three height-dependent layer
support that heating process should occur on the downflow patches in
the middle of layer.
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Title: How Well Can a Footpoint Tracking Method Estimate the Magnetic
Helicity Influx during Flux Emergence?
Authors: Choe, Gwangson; Kim, Sunjung; Kim, Kap-Sung; No, Jincheol
2015IAUGA..2254507C Altcode:
As shown by Démoulin and Berger (2003), the magnetic helicity
flux through the solar surface into the solar atmosphere can be
exactly calculated if we can trace the motion of footpoints with
infinite temporal and spatial resolutions. When there is a magnetic
flux transport across the solar surface, the horizontal velocity of
footpoints becomes infinite at the polarity inversion line, although
the surface integral yielding the helicity flux does not diverge. In
practical application, a finite temporal and spatial resolution causes
an underestimate of the magnetic helicity flux when a magnetic flux
emerges from below the surface, because there is an observational
blackout area near a polarity inversion line whether it is pre-existing
or newly formed. In this paper, we consider emergence of simple
magnetic flux ropes and calculate the supremum of the magnitude of
the helicity influx that can be estimated from footpoint tracking. The
results depend on the ratio of the resolvable length scale and the flux
rope diameter. For a Gold-Hoyle flux rope, in which all field lines
are uniformly twisted, the observationally estimated helicity influx
would be about 90% of the real influx when the flux rope diameter is
one hundred times the spatial resolution (for a large flux rope), and
about 45% when it is ten times (for a small flux rope). For Lundquist
flux ropes, the errors incurred by observational estimation are smaller
than the case of the Gold-Hoyle flux rope, but could be as large as
30% of the real influx. Our calculation suggests that the error in
the helicity influx estimate is at least half of the real influx or
even larger when small scale magnetic structures (less than 10,000 km)
emerge into the solar atmosphere.
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Title: Mass and Energy of Erupting Solar Plasma Observed with the
X-Ray Telescope on Hinode
Authors: Lee, Jin-Yi; Raymond, John C.; Reeves, Katharine K.; Moon,
Yong-Jae; Kim, Kap-Sung
2015ApJ...798..106L Altcode: 2014arXiv1411.2229L
We investigate seven eruptive plasma observations by Hinode/XRT. Their
corresponding EUV and/or white light coronal mass ejection features are
visible in some events. Five events are observed in several passbands
in X-rays, which allows for the determination of the eruptive plasma
temperature using a filter ratio method. We find that the isothermal
temperatures vary from 1.6 to 10 MK. These temperatures are an average
weighted toward higher temperature plasma. We determine the mass
constraints of eruptive plasmas by assuming simplified geometrical
structures of the plasma with isothermal plasma temperatures. This
method provides an upper limit to the masses of the observed eruptive
plasmas in X-ray passbands since any clumping causes the overestimation
of the mass. For the other two events, we assume the temperatures are
at the maximum temperature of the X-ray Telescope (XRT) temperature
response function, which gives a lower limit of the masses. We find
that the masses in XRT, ~3 × 10<SUP>13</SUP>-5 × 10<SUP>14</SUP>
g, are smaller in their upper limit than the total masses obtained by
LASCO, ~1 × 10<SUP>15</SUP> g. In addition, we estimate the radiative
loss, thermal conduction, thermal, and kinetic energies of the eruptive
plasma in X-rays. For four events, we find that the thermal conduction
timescales are much shorter than the duration of eruption. This result
implies that additional heating during the eruption may be required
to explain the plasma observations in X-rays for the four events.
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Title: Systematic Effects on the Genus Topology of the Large-scale
Structure of the Universe
Authors: Kim, Young-Rae; Choi, Yun-Young; Kim, Sungsoo S.; Kim,
Kap-Sung; Lee, Jeong-Eun; Shin, Jihye; Kim, Minbae
2014ApJS..212...22K Altcode: 2014arXiv1404.6314K
The large-scale structure of the universe is a useful cosmological probe
of primordial non-Gaussianity and the expansion history of the universe
because its topology does not change with time in the linear regime in
the standard paradigm of structure formation. However, when the topology
of iso-density contour surfaces is measured from observational data,
many systematic effects are introduced due to the finite size of pixels
used to define the density field, nonlinear gravitational evolution,
redshift space distortion, shot noise (discrete sampling), and bias
in the distribution of the density field tracers. We study the various
systematic effects on the genus curve to a great accuracy by using the
Horizon Run 2 simulation of a ΛCDM cosmology. We numerically measure
the genus curve from the gravitationally evolved matter and dark matter
halo density fields. It is found that all the non-Gaussian deviations
due to systematic effects can be modeled by using a few low-order
Hermite polynomials from H <SUB>0</SUB> to H <SUB>4</SUB>. We compare
our results with analytic theories whenever possible, and find many new
terms in the Hermite series that are making significant contributions
to the non-Gaussian deviations. In particular, it is found that the
amplitude drop of the genus curve due to the nonlinear gravitational
evolution can be accurately modeled by two terms, H <SUB>0</SUB> and
H <SUB>2</SUB>, with both coefficients proportional to \sigma _0^2,
the mean-square density fluctuation.
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Title: Temperature and mass estimation of erupting plasma associated
with coronal mass ejections observed by Hinode/XRT and SDO/AIA
Authors: Lee, Jin-Yi; Raymond, John C.; Reeves, Kathy; Moon, Yong-Jae;
Kim, Kap-Sung
2014AAS...22421836L Altcode:
We investigate the temperature and mass of erupting plasma observed in
X-ray and EUV, which are associated with coronal mass ejections (CMEs)
and X-class flares. Hinode/XRT observed the erupting hot plasma in a
few passbands, which allows us to determine the temperature of the
plasma using a filter ratio method. SDO/AIA observed the erupting
plasma in EUV passbands. We estimate the temperatures and emission
measures of the erupting plasma in EUV using a differential emission
measure method. One of these observations shows an eruptive plasma
with a loop-like structure in X-ray and EUV. The temperature of the
erupting plasma in X-ray is about 13 MK by the filter ratio method. The
estimated mass of this erupting plasma in X-ray is similar to that in
EUV. A couple of events are associated with the eruptions of prominences
as absorption features in EUV in addition to hot plasma eruption. One
event shows that the absorption features change to emission features at
the beginning of their eruptions in all EUV wavelengths of SDO/AIA. By
estimating the temperature and mass of the erupting plasmas, we discuss
the heating of the plasmas associated with coronal mass ejections in
the low corona.
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Title: Coronal Thick Target Hard X-Ray Emissions and Radio Emissions
Authors: Lee, Jeongwoo; Lim, Daye; Choe, G. S.; Kim, Kap-Sung;
Jang, Minhwan
2013ApJ...769L..11L Altcode: 2013arXiv1304.5517L
A distinctive class of hard X-ray (HXR) sources located in the corona
was recently found, which implies that the collisionally thick target
model (CTTM) applies even to the corona. We investigated whether
this idea can be independently verified by microwave radiations
which have been known as the best companion to HXRs. This study
is conducted on the GOES M2.3 class flare which occurred on 2002
September 9 and was observed by the Reuven Ramaty High-Energy Solar
Spectroscopic Imager and the Owens Valley Solar Array. Interpreting
the observed energy-dependent variation of HXR source size under the
CTTM, the coronal density should be as high as 5 × 10<SUP>11</SUP>
cm<SUP>-3</SUP> over a distance of up to 12”. To explain the cutoff
feature of the microwave spectrum at 3 GHz, however, we require a
density no higher than 1 × 10<SUP>11</SUP> cm<SUP>-3</SUP>. Additional
constraints must be placed on the temperature and magnetic field of
the coronal source in order to reproduce the microwave spectrum as a
whole. First, a spectral feature called the Razin suppression requires
a magnetic field in a range of 250-350 G along with high viewing angles
around 75°. Second, to avoid excess fluxes at high frequencies due to
the free-free emission that was not observed, we need a high temperature
>=2 × 10<SUP>7</SUP> K. These two microwave spectral features,
Razin suppression and free-free emissions, become more significant at
regions of high thermal plasma density and are essential for validating
and determining additional parameters of the coronal HXR sources.
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Title: Characteristic dimension of electromagnetic ion cyclotron
wave activity in the magnetosphere
Authors: Lee, Jeongwoo; Min, Kyungguk; Kim, Kap-Sung
2013JGRA..118.1651L Altcode:
In this paper, we estimate the size of coherent activity of
electromagnetic ion cyclotron (EMIC) waves using the multi-spacecraft
observations made during the Time History of Events and Macroscale
Interactions during Substorms (THEMIS) mission. We calculate the
cross-correlations between EMIC wave powers measured by different
THEMIS spacecraft, plot them over the separation distances between
pairs of observing spacecraft, and determine the 1/e folding distance
of the correlations as the characteristic dimension of the coherent
wave activity. The characteristic radius in the direction transverse
to the local magnetic field is found to lie in rather a wide range of
1500-8600 km varying from the AM to PM sectors and also from hydrogen
to helium bands. However, the characteristic dimensions normalized
by either gyroradius or wavelength fall into narrower ranges almost
independent of the emission band and event location. Specifically, the
coherent dimension is found to be 10-16 times gyroradius of 100 keV
protons and 2-3 times local wavelength. The former may give a useful
scale for the source dimension, and the latter suggests that the EMIC
wave activity maintains coherency only up to a couple of wavelengths.
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Title: The Challenge of the Largest Structures in the Universe
to Cosmology
Authors: Park, Changbom; Choi, Yun-Young; Kim, Juhan; Gott, J. Richard,
III; Kim, Sungsoo S.; Kim, Kap-Sung
2012ApJ...759L...7P Altcode: 2012arXiv1209.5659P
Large galaxy redshift surveys have long been used to constrain
cosmological models and structure formation scenarios. In particular,
the largest structures discovered observationally are thought to
carry critical information on the amplitude of large-scale density
fluctuations or homogeneity of the universe, and have often challenged
the standard cosmological framework. The Sloan Great Wall (SGW) recently
found in the Sloan Digital Sky Survey (SDSS) region casts doubt on
the concordance cosmological model with a cosmological constant
(i.e., the flat ΛCDM model). Here we show that the existence of
the SGW is perfectly consistent with the ΛCDM model, a result that
only our very large cosmological N-body simulation (the Horizon Run
2, HR2) could supply. In addition, we report on the discovery of a
void complex in the SDSS much larger than the SGW, and show that such
size of the largest void is also predicted in the ΛCDM paradigm. Our
results demonstrate that an initially homogeneous isotropic universe
with primordial Gaussian random phase density fluctuations growing in
accordance with the general relativity can explain the richness and
size of the observed large-scale structures in the SDSS. Using the HR2
simulation we predict that a future galaxy redshift survey about four
times deeper or with 3 mag fainter limit than the SDSS should reveal
a largest structure of bright galaxies about twice as big as the SGW.
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Title: Three-dimensional simulations of the lunar sodium exosphere
and its tail
Authors: Lee, Dong-Wook; Kim, Sang J.; Lee, Dong-Hun; Jin, Ho; Kim,
Kap-Sung
2011JGRA..116.7213L Altcode:
The brightness distributions of the lunar sodium exosphere reported
by Flynn and Mendillo (1993) and the receding velocities of the lunar
sodium tail observed by Mierkiewicz et al. (2006) are reproduced by
3-D Monte Carlo simulations. We consider the effects of two spatially
different sodium sources simultaneously: dayside source with the
dependency of solar zenith angle and an isotropic source due to
micrometeoroid impact. In the simulations, the following effects
are taken into account: (1) the gravity of the Moon, the Earth, and
the Sun with the orbital motion of the Moon; (2) photoionizations,
solar radiation pressure, and returns to the lunar surface; and (3)
the shadows of the Earth and Moon. The sodium brightness observed
by Flynn and Mendillo (1993) is successfully modeled, from which the
most probable source ratio between the isotropic and dayside sources is
estimated to be 70%∼80%: 30%∼20%, respectively. The best coma model
provides an initial velocity of 2.0 km/s with a narrow Doppler width of
0.2 km/s and a total production rate of 0.7 × 10<SUP>22</SUP>/s. On the
basis of the best 3-D lunar coma model, we also simulate the receding
velocity distribution of lunar sodium tail, and we find satisfactory
models for high receding velocity and its wide dispersion observed
by Mierkiewicz et al. (2006) considering the effect of variable solar
radiation pressure and appropriate ionization times.
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Title: Prediction of Communication Outage Period between Satellite
and Earth station Due to Sun Interference
Authors: Song, Yongjun; Kim, Kap-Sung; Jin, Ho; Lee, Byoung-Sun
2010JASS...27...31S Altcode:
Geostationary satellites are located at an altitude of approximately
35,786km above the equator, and revolve in the same angular velocity
as earth. Geostationary satellites can therefore, communicate with a
ground earth station at all times. However, geostationary satellites
also experience communication failure time, twice a year, closely one
upon the other in spring and autumn quarters. The communication errors
occur when ground station-satellite-the Sun are aligned closely, which
occurs during spring and fall equinoxes. At such times, thermal noise
emitted from the Sun's surface hits the rear side of the satellite and
flows directly into the earth station antenna. This is called solar
interference. Studies on duration calculation methods and prediction
results of a solar interference phenomenon were implemented by many
scientists (Vuong & Forsey 1983, Mohamadi & Lyon 1988, Lin &
Yang 1989) abroad, and also by Lee et al. (1991) in Korea. To calculate
the time of solar interference, information on precise position of the
Sun and earth station antenna systems is necessary. Previous researches
used the formula of Van Flandern (Van Flandern & Pulkkinen 1979)
when calculating the Sun's position, but it has position error of
about 1 arcmin. Using the precise ephemeris DE406, which published
by NASA/JPL and the earth ellipsoid model, the study calculated the
precise positioning of the Sun as causing error within 10 arcsec. For
the verification of the calculation, we used TU media ground station
located in Seongsu-dong and the MBSAT satellite operated by TU media.
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Title: The system design of TRIO cinema Mission
Authors: Jin, Ho; Seon, Jongho; Kim, Khan-Hyuk; Lee, Dong-Hun; Kim,
Kap-Sung; Lin, Robert; Parks, George; Tindall, Craig; Horbury, T. S.;
Larson, Davin; Sample, John
2010cosp...38.1923J Altcode: 2010cosp.meet.1923J
TRIO (Triplet Ionospheric Observatory) CINEMA ( Cubesat for Ion,
Neutral, Electron, MAg-netic fields) is a space science mission
with three identical cubesats. The main scientific objec-tives
are a multi-observation of ionospheric ENA (Energetic Neutral Atom)
imaging, ionospheric signature of suprathermal electrons and ions and
complementary measurements of magnetic fields for particle data. For
this, Main payloads consist of a suprathermal electron, ion, neutral
(STEIN) instrument and a 3-axis magnetometer of magnetoresistive
sensors. The CINEMA is a 3-unit CubeSat, which translates to a 10 cm
x 10 cm x 30 cm in volume and no more than four kilograms in mass. An
attitude control system (ACS) uses torque coils, a sun sensor and
the magnetometers and spin CINEMA spcaecraft 4 rpm with the spin
axis perpendicular to the ecliptic plane. CINEMA will be placed into
a high inclination low earth orbit that crosses the auroral zone and
cusp. Three institutes are collaborating to develop CINEMA cubesats:
i) two cubesats by Kyung Hee University (KHU) under their World Class
University (WCU) program, ii) one cubesat by UC Berkeley under the NSF
support, and iii) three magnetometers are provide by Imperial College,
respectively. In this paper, we describe the system design and their
performance of TR IO cinema mission. TRIO cinema's development of
miniature in-strument and spacecraft spinning operation will play an
important role for future nanosatellite space missions
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Title: Estimate of Coronal Magnetic Field Strength Using Plasmoid
Acceleration Measurement
Authors: Jang, Min-Hwan; Choe, G. S.; Lee, K. S.; Moon, Y. J.; Kim,
Kap-Sung
2009JKAS...42..175J Altcode:
No abstract at ADS
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Title: Synthetic high-resolution near-IR spectra of the Sun for
planetary data reductions made from ATMOS/Spacelab-3 and Atlas-3 data
Authors: Seo, Haingja; Kim, Sang J.; Hwang, Sungwon; Jung, Aeran;
Kim, Ji Hyun; Kim, Joo Hyeon; Kim, Kap-Sung; Lee, Jinny; Jang, Minhwan
2007Icar..192..287S Altcode:
We have constructed synthetic solar spectra for the 2302-4800 cm
<SUP>-1</SUP> (2.08-4.34 μm) range, a spectral range where planetary
objects mainly emit reflected sunlight, using ATMOS (Atmospheric
Trace Molecule Spectroscopy)/Spacelab-3 and Atlas-3 spectra, of which
resolution is 0.01 cm <SUP>-1</SUP>. We adopted Voigt line profiles for
the modeling of line shapes based on an atlas of line identifications
compiled by Geller [Geller, M., 1992. Key to Identification of Solar
Features. A High-Resolution Atlas of the Infrared Spectrum of the
Sun and the Earth Atmosphere from Space. NASA Reference Publ. 1224,
vol. III. NASA, Washington, DC, pp. 1-22], who derived solar line
positions and intensities from contaminated high-resolution solar
spectra obtained by ATMOS/Spacelab-3. Because the ATMOS spectra in
these wavelength ranges are compromised by absorption lines of molecules
existing in Earth's high-altitude atmosphere and in the compartment of
the spacecraft, the direct use of these high-resolution solar spectra
has been inconvenient for the data reductions of planetary spectra. We
compared the synthetic solar spectra with the ATMOS spectra, and
obtained satisfactory fits for the majority of the solar lines with
the exception of abnormal lines, which do not fit with Voigt line
profiles. From the model fits, we were able to determine Voigt line
parameters for the majority of solar lines; and we made a list of the
abnormal lines. We also constructed telluric-line-free solar spectra by
manually eliminating telluric lines from the ATMOS spectra and filling
the gaps with adjacent continua. These synthetic solar spectra will be
useful to eliminate solar continua from spectra of planetary objects
to extract their own intrinsic spectral features.
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Title: Two-Step Reconnections in a C3.3 Flare and Its Preflare
Activity Observed by Hinode XRT
Authors: Kim, Sujin; Moon, Young-Jae; Kim, Khan-Hyuk; Kim, Yeon-Han;
Sakurai, Takashi; Chae, Jongchul; Kim, Kap-Sung
2007PASJ...59S.831K Altcode:
We investigated the evolution of a C3.3 impulsive flare and its
preflare activity, which occurred in NOAA Active Region 10923 on 2006
November 12, using Hinode X-Ray Telescope (XRT) data. For an extensive
investigation, we also used GOES X-ray flux, TRACE 171Å, and SOHO MDI
data. Examining the time-series of the XRT and TRACE images, we can
identify the following evolutionary sequences: (1) There were three
bundles of loops along the sheared polarity inversion line forming a
sigmoidal structure during the preflare phase. (2) Preflare brightening
occurred between two upper-loop bundles, and they consequently formed
one larger bundle. (3) The main flare occurred near the location
where this new loop bundle and the third bundle met together. (4) As a
result, a single stacked loop structure was formed. This morphological
evolution of the X-ray loops is quite consistent with a tether-cutting
model involving a single-bipole explosion. Our result shows that the
preflare and the main flare in this event are a two-step reconnection
process, which strongly suggests that the preflare activity plays an
important role in triggering the main flare.
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Title: Component-Based Development of Observational Software for
KASI Solar Imaging Spectrograph
Authors: Choi, Seong-Hwan; Kim, Yeon-Han; Moon, Yong-Jae; Choi,
Kyung-Seok; Park, Young-Deuk; Jang, Bi-Ho; Kim, Su-Jin; Kim, Kap-Sung
2005JKAS...38..463C Altcode:
No abstract at ADS
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Title: A Study of Flare-associated X-Ray Plasma
Ejections. I. Association with Coronal Mass Ejections
Authors: Kim, Yeon-Han; Moon, Y. -J.; Cho, K. -S.; Kim, Kap-Sung;
Park, Y. D.
2005ApJ...622.1240K Altcode:
We have made a comprehensive statistical study of the relationship
between flare-associated X-ray plasma ejections and coronal mass
ejections (CMEs). For this we considered all flare-mode data in Yohkoh
SXT observations from 1999 April to 2001 March and then selected 279
limb flares seen at longitudes greater than 60°. For these events,
we identified whether there were associated X-ray plasma ejections
or not. We found that about half (137/279) of the flares have X-ray
plasma ejections, and we present a comprehensive list of these with
their event times and speeds. We then determined whether there was an
association between the flares with plasma ejections and CMEs detected
by the Solar and Heliospheric Observatory LASCO instrument, on the
basis of temporal and spatial proximity. It is found that about 69%
(95/137) of the X-ray plasma ejections are associated with CMEs and
that about 84% (119/142) of the events without plasma ejections do
not have related CMEs. The associations are found to increase with
flare strength and duration. We find that X-ray plasma ejections occur
nearly simultaneously with the hard X-ray flare peak, supporting the
idea that the X-ray plasma ejections are tightly associated with the
flaring process. When the CMEs are extrapolated into the Yohkoh field
of view for 43 selected, well-observed events, it is found that about
80% of the CMEs preceded X-ray plasma ejections, by approximately
20 minutes on average. Our results show that X-ray plasma ejections
usually do not represent the early signature of a CME's leading edge
but are closely associated with CMEs.
---------------------------------------------------------
Title: High-Speed x-ray Jets Associated with the 18 June 1999
Limb Flares
Authors: Kim, Yeon-Han; Kim, Kap-Sung; Jang, Minhwan
2001SoPh..203..371K Altcode:
Peculiar high-speed X-ray jets associated with the 18 June 1999 limb
flares have directly been observed with the soft X-ray Telescope
(SXT) aboard Yohkoh. The jets have a much shorter lifetime (within
200 s) and a much larger velocity (∼ 1700 km s<SUP>−1</SUP>)
than the previously reported jets. Judged from their large velocity,
the kinetic energy of the jets is approximately one order of magnitude
larger than the thermal energy content, which is far different from
the jets previously reported by other researchers. Here we present
the preliminary results and discuss the particular features of the jets.
---------------------------------------------------------
Title: New Digital H-alpha Observation by Solar Flare Telescope
at BOAO
Authors: Lee, C. -W.; Moon, Y. -J.; Park, Y. D.; Jang, B. -H.; Kim,
Kap-Sung
2001JKAS...34..111L Altcode:
Recently, we have set up a new digital CCD camera system,
MicroMax YHS-1300 manufactured by Roper Scientific for H-alpha
observation by Solar Flare Telescope at Bohyunsan Optical Astronomical
Observatory. It has a 12 bit dynamic range, a pixel number of 1300x1030,
a thermoelectric cooler, and an electric shutter. Its readout speed is
about 3 frames per second and the dark current is about 0.05 e-/p/s at
-10 C degree. We have made a system performance test by confirming the
system linearity, system gain, and system noise that its specification
requires. We have also developed a data acquisition software which
connects a digital camera controller to a PC and acquires H-alpha
images via Microsoft C++ 6.0 under Windows 98. Comparisons of high
quality H-alpha images of AR 9169 and AR 9283 obtained from SOFT with
the corresponding images from Learmonth Solar Observatory in Australia
confirm that our H-alpha digital observational system is performed
properly. Finally, we present a set of H-alpha images taken from a
two ribbon flare occurred in AR 9283.
---------------------------------------------------------
Title: Prediction of 23rd Solar Cycle Using the Statistical and
Precursor Method
Authors: Jang, Se Jin; Kim, Kap-Sung
1999PKAS...14...91J Altcode:
We have made intensive calculations on the maximum relative sunspot
number and the date of solar maximum of 23rd solar cycle, by using
the statistical and precursor methods to predict solar activity
cycle. According to our results of solar data processing by statistical
method, solar maximum comes at between February and July of 2000 year
and at that time, the smoothed sunspot number will reach to 114.3
122.8. while precursor method gives rather dispersed value of 118 171
maximum sunspot number. It is found that prediction by statistical
method using smoothed relative sunspot number is more accurate than by
any method to use any data of 10.7cm radio fluxes and geomagnetic aa,
Ap indexes, from the full analysis of solar cycle pattern of these
data. In fact, current ascending pattern of 23rd solar cycle supports
positively our predicted values. Predicted results by precursor method
for Ap<SUB>avg</SUB> , aa_{31-36} indexes show similar values to those
by statistical method. Therefore, these indexes can be used as new
precursors for the prediction of 23rd or next solar cycle.
---------------------------------------------------------
Title: The Prediction of Solar Activity for Solar Maximum
Authors: Lee, Jinny; Jang, Se Jin; Kim, Yeon Han; Kim, Kap-Sung
1999PKAS...14..103L Altcode:
We have investigated the solar activity variation with period shorter
than 1000 days, through Fourier transformation of solar cycle 21 and 22
data. And real time predictions of the flare maximum intensity have been
made by multilinear regression method to allow the use of multivariate
vectors of sunspot groups or active region characteristics. In addition,
we have examined the evolution of magnetic field and current density
in active regions at times before and after flare occurrence, to check
short term variability of solar activity. According to our results
of calculation, solar activity changes with periods of 27.1, 28.0,
52.1, 156.3, 333.3 days for solar cycle 21 and of 26.5, 27.1, 28.9,
54.1, 154, 176.7, 384.6 days for solar cycle 22. Periodic components
of about 27, 28, 53, 155 days are found simultaneously at all of two
solar cycles. Finally, from our intensive analysis of solar activity
data for three different terms of 1977 ~ 1982, 1975 ~ 1998, and 1978 ~
1982, we find out that our predictions coincide with observations at
hit rate of 76%, 63%, 59% for all class flare and of 86%, 27%, 55%
for M class flare respectively.
---------------------------------------------------------
Title: Polarization-Magnetic Field Calibration Curve
Authors: Kim, Kap-Sung
1997PKAS...12....1K Altcode:
We have obtained theoretical calibration curves to convert the amount
of polarization into the strength of magnetic field, by a numerical
calculation of radiation transfer for the polarized spectral line of FeI
6303A. In our calculation, three kinds of atmospheric models (VAL-C,
penumbra, umbra) have been used to make a proper calibration for an
active region composed of quiet, penumbral and umbral areas. It was
found that firstly, the results of our calculation depend highly on a
kind of atmospheric model rather than on any other input parameters
used in a model. Secondly, observed line profile showed in solar
spectrum atlas proved to be very similar to the calculated profiles
obtained by using a penumbral model. Finally, another method except
this calibration curve should be developed to estimate correctly
the distribution of magnetic field in solar active region from the
observation of polarized spectral line.
---------------------------------------------------------
Title: The Prediction of Flare Production Using Solar Activity Data
Authors: Lee, Jinny; Kim, Kap-Sung
1996PKAS...11..263L Altcode:
We have intensively carried out numerical calculations on flare
predictions from the solar activity data for photospheric sunspots,
chromospheric flare and plages, coronal X-ray intensities and 2800MHz
radio fluxes, by using multilinear regression method. Intensities of
solar flares for the next day have been predicted from the solar data
between 1977-1982 and 1993-1996. Firstly, we have calculated flare
predictions with the multilinear regression method, by using separate
solar data in growth and decay phase of sunspot area and magnetic field
strength from the whole data on solar activities. Secondly, the same
operations as above have been made for the remaining data after removal
of the data with large deviation from the mean calculated by the above
prediction method. We have reached a conclusion that average hit ratio
of correct predictions to total predictions of flares with class of
M5 over has been as high as 70% for the first case and that of correct
prediction number to total observation number has been shown as 61%.
---------------------------------------------------------
Title: Structure of the Photospheric Vector Magnetic Fields
Authors: Cho, Kyung Seok; Kim, Kap-Sung
1995PKAS...10...91C Altcode:
We have intensively examined the structure of photospheric magnetic
fields obtained from the calculation of the polarized radiation transfer
for the model atmosphere. To determine more reliable magnetic field in
the photospheric region composed of umbra, penumbra and quiet area, we
have calculated the polarized radiative transfer for a magnetically
sensitive spectral line, FeI 6302.5A, using out composite model
representing three kinds of the atmospheric area distinguished by the
pixel value of the Stokes I image over the region. Polarization data
of the full Stokes parameters, used in this paper had been obtained
from the vector magnetograph on Solar Flare Telescope of National
Astronomical at Mitaka(MTK) in Japan. According to our investigation
on the active region in the photosphere, it has been found that the
large current density(=> 8x10^2 A/km^2) and shear angle(=>
85 deg) should be distributed along the magnetic neutral line. To be
compared with the results of MTK, our results in transverse magnetic
field strength and direction are similar with those of MTK, however
our longitudinal field strength at the center of the spot is somewhat
(~1000 Gauss) larger than MTK.
---------------------------------------------------------
Title: Development of a Computer Program for Astronomical Image Data
Processing by Observational Equipment in Astronomical Observatory
of Kyung Hee University
Authors: Kim, Kap-Sung
1995PKAS...10..135K Altcode:
We have developed a graphic software for image processing of
astronomical data obtained by observational equipment in Astronomical
Observatory of Kyung Hee University. The essential hardware for running
our computer program is simply composed of a PC with the graphic
card to handle 256 colors and the color graphic monitor, including
CCD camera system. Our software has been programmed in WINDOWS to
provide good environments for users, by using various techniques of
image processing on astronomical image data recorded in FITS format
by KHCCD program(Jin and Kim,1994) with a compressional mode. We are
convinced that our results will be a fundamental and useful technique
in the construction of data processing system and can be effectively
used in any other observatories, as well as in data processing system
of Kyung Hee University.
---------------------------------------------------------
Title: Development of System Software for Astronomical Observations
by CCD Photometric System in Astronomical Observatory of Kyung
Hee University
Authors: Jin, Ho; Kim, Kap-Sung
1994PKAS....9..101J Altcode:
We have investigated intensively an optical telescope with 76cm
diameter and CCD camera system in astronomical observatory of Kyung
Hee university, in order to maximize instrumental functions of our
observational equipments and to construct a more reliable photometric
system. And computer softwares AUTO DOME, KH CCD and KH PHO for
astronomical image observations and their automatic photometries with
high accuracy have been made for observers to use our observational
system conveniently and efficiently. Throughout careful examinations
of these programs, it has been proved that the observing time by
our program is shorter than that by manual operations, so that,
fast and accurate observations can be executed with ease. For open
cluster NGC 7063 observed with S/N value of 350 or more by KH PHO,
we have found the magnitude measurements of 11 object stars would
show 0.007 magnitude difference, comparing with magnitude data from
IRAF/APPHOT. From automatic photometry of eclipsing binary, AB And
observed by our software, total 220 data points with good quality
have been acquired during 8 hours and so we could make a better light
curve than that obtained from any observational results by domestic
photoelectric photometry system.
---------------------------------------------------------
Title: Numerical Method for the Astronomical Almanac and Orbit
Calculations
Authors: Kim, Kap-Sung
1993PKAS....8..137K Altcode:
We have calculated the astronomical almanac 1994 and simulated the
trajectory of a satellite orbit considering all perturbative forces
with various initial conditions. In this work, Gauss Jackson multistep
integration method has been used to calculate our basic equation of
motion with high numerical accuracy. It has been found that our results
agree well with the Astronomical Almanac Data distributed by JPL of
NASA and the orbit simulations have been carried out with fast speed,
stability and excellent round-off error accumulation, comparing with
other numerical methods. In order to be carried out our works on almanac
and orbit calculations easily by anyone who uses a personal computer,
we have made a computer program on graphical user interface to provide
various menus for detail works selected by a mouse.
---------------------------------------------------------
Title: Graphic Library for Astronomical Image Processing
Authors: Kim, Kap-Sung; Hong, Seung Soo
1992PKAS....7..261K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Doppler Analysis of Spectral Line Profiles
Authors: Kim, Kap-Sung; Sim, Kyung Jin; Park, Young Deuk; Yun, Hong Sik
1991PKAS....6...16K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Graphic Library for Astronomical Calculations
Authors: Kim, Kap-Sung; Minn, Young Key
1990PKAS....5...95K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Atomic Spectra of Non-Thermal Equilibrium Atmospheres
Authors: Kim, Kap-Sung
1990PKAS....5...40K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Fine Structure of Quiescent Prominences
Authors: Kim, Kap-Sung
1990JKAS...23...31K Altcode:
Fine structures of a quiescent prominence are studied by analyzing
high resolution H alpha filtergrams and H alpha line spectra observed
observed at the Hida Observatory of Kyoto University. We have found two
kinds of downward motions in the prominence. One of them is a movement
with a constant acceleration below the solar gravity(=1/4g_s) and the
other with an uniform velocity(=16Km/s). The average life time and
the size of prominence knots are estimated to be about 7 minutes and
4000Km, respectively. Spatial and brightness distribution of knots are
also presented in this paper. With the analytical solutions derived
from magnetostatic equilibrium in the prominence, we have examined
the filamentary structure based on the Kippenhahn-Schluter model. Sag
angles of the magnetic fields supporting the prominence matter are
predicted from the observed density profile.
---------------------------------------------------------
Title: Hydrogen Emission Spectra of Quiescent Prominences
Authors: Kim, Kap-Sung
1990JKAS...23...71K Altcode:
Theoretical calculations of the combined radiative transfer and
statistical equilibrium equation including the charge-particle
conservations have been carried out for a multilevel hydrogen atom in
quiescent prominences. Cool and dense models show the steep changes of
population and radiation field in the vicinity of the surface, while
these physical quantities remain unchanged for models with temperature
of 7,300K, regardless of total densities. Ionization rate of hydrogen
atom related with metallic line formation varies in considerable
amounts from the surface to the center of model prominences cooler than
6,300K. However, such cool models cannot release enough hydrogen line
emissions to explain observed intensities. Prominence models with a
temperature higher than 8,000K can yield the centrally reversed Lyman
line profiles confirmed by satellite EUV observations. We find that
quiescent prominence with a density between 2x10^11 and 10^12 cm^-3
should be in temperature range between 6,300K and 8,300K, in order
to explain consistently observed H alpha, beta line emissions and
n_p/n_1 ratio.
---------------------------------------------------------
Title: Emitting region of sodium lines in solar prominences
Authors: Kim, Kap-Sung
1988SoPh..114...47K Altcode:
We have calculated the emission spectra of hydrogen and sodium atoms
in the cool part of prominence models which satisfy simultaneously
the constraints of radiative transfer, statistical equilibrium and
charge-particle conservations.
---------------------------------------------------------
Title: Emitting region of sodium lines in solar prominences
Authors: Kim, Kap-Sung
1987SoPh..114...47K Altcode:
The emission spectra of hydrogen and sodium atoms in the cool part
of prominence models which satisfy simultaneously the constraints
of radiative transfer, statistical equilibrium and charge-particle
conservations have been calculated. In the considered range of the
model parameters, emission strengths of H-alpha and NaI D lines
increase with temperature and total number density. Low-pressure
models raise the ionization rate significantly but yield very weak
NaI D line intensities, since these model prominences contain small
amounts of free electrons and sodium atoms which have a deep relation
with the formation of sodium lines. It is found that sodium D lines
should be emitted in the high pressure region of prominences, and
that their intensities are difficult to attain in the cool core of
any model prominence with a temperature as low as 4000 K. In order to
explain consistently the spectral emissions of H-alpha and NaI D lines
observed in quiescent prominences, a total number density higher than
4 x 10 to the 11th/cu cm and a temperature over 5000 K are required,
at least in the cool part of prominences.
---------------------------------------------------------
Title: A Small-Scale Energy Release Observed on the Limb - Part One -
the Broadened Components of d3 Emission Lines
Authors: Kawaguchi, Ichiro; Kim, Kap-Sung; Nakai, Yoshihiro
1986SoPh..106...47K Altcode:
The D3 emission lines observed on the emerging flux loops and mound
prominences above the limb were locally found to consist of two
components, i.e., the main and the broadened components. A number of
Doppler shifted emission lines, separated distinctly from the main body
of the emission lines were also detected, which we call the separated
components. On the sequential spectrograms, the lifetimes of these
broadened and separated components were obtained and their histograms
were made.
