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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Astronomy and Space Sciences
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The Korean Space Science Society
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Volume & Issues
Volume 6, Issue 2 - Dec 1989
Volume 6, Issue 1 - Jun 1989
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Three Dimensional Computer Modeling of Magnetospheric Substorm
Min, Kyoung-W. ;
Journal of Astronomy and Space Sciences, volume 6, issue 1, 1989, Pages 1~15
Magnetospheic substorm in the magnetotail region is studied numerically by means of a three dimensional MHD code. The analytic solution for the quiet magnetotail is employed as an initial configuration. The localized solar wind is modeled to enter the simulation domain through the boundaries located in the magnetotail lobe region. As a result of the interaction between the solar wind and the magnetosphere, the magnetic field lines are stretched, and the plasma sheet becomes thinner and thinner. When the current driven resistivity is generated, magnetic reconnection is triggered by this resistivity. The resulting plasma jetting is found to be super-magnetosonic. Although the plasmoid formation and its tailward motion is not quite clear as in the two dimensional simulation, which is mainly because of the numerical model chosen for the present simulation, the rarification of the plasmas near the x-point is observed. Field aligned currents are observed in the late expansive stage of the magnetospheric substorm. These field aligned currents flow from the tail toward the ionosphere on the dawn side from the ionosphere to ward the tail on the dusk side, namely in the same sense of the region 1 current. As the field aligned currents develop, it is found that the cross tail current in the earth side midnight section of the magnetic x-point is reduced.
ON THE DYNAMICAL STRUCTURE OF THE JET SYSTEM IN THE DISK WITH THE KEPLERIAN ROTATION
Journal of Astronomy and Space Sciences, volume 6, issue 1, 1989, Pages 17~28
The classical solar wind theory proposed by Parker(1963) explains well the dynamics of the wind pheonomena such as stellar wind and accretion disk. While the stellar wind system like the solar wind has the spherically symmetric wind structure, there are various jet phenomena which collimate the system into the narrow space. We can find these dynamical structures in SS433, in the optical jet of M87, and around the active galactic nulei. We present the dynamical structure of the jet system in disks, which conserves the angular monetum, with the Keplerian rotation and the strong relation between the geometrical cross section and the physical change of the jet stream on the basis of the hydrodynamic equations.
THE INSTABILITY OF INFINITE DISK SYSTEM WITH THE MAGNETIC FIELD
Journal of Astronomy and Space Sciences, volume 6, issue 1, 1989, Pages 29~39
The instability of the infinite disk system with the effect of the surrounding magnetic field has been investigated and the initial mass function has been obtained. We present the fact that the infinite system becomes unstable by the long wavelength perturbation if the magnetic pressure is greater than the gas pressure, on the other hand, it also becomes unstable by the short wavelength perturbation if the gas pressure is greater than the magnetic pressure.
PHOTOELECTRIC OBSERVATIONS OF HD 8358
Journal of Astronomy and Space Sciences, volume 6, issue 1, 1989, Pages 41~47
UBV photoelectric observations of RS CVn type variable star HD 8358 were made using the 61cm reflector at Sobaeksan Astronomical Observatory. The data were obtained on 15 nights from October 1987 to December 1988. Double peaks of maximum light is seen from the light curve and continuous change of phase in notified from the times of maximum lights. The colors of October, 1987 - January, 1988 observations are bluer in
, but redder in
, than those of November -December, 1988 observations.
THE STAR CALLED "CHI-SHIH" THAT WASN'T
Chen, Kwan-Yu ;
Journal of Astronomy and Space Sciences, volume 6, issue 1, 1989, Pages 49~55
PHOTOGRAPHIC AND PHOTOELECTRIC OBSERVATIONS OF COMET P/HALLEY IN 1985-86
Nha, Il-Seong ; Lee, Yong-Sam ; Kim, Ho-Il ; Chun, Yong-Woo ;
Journal of Astronomy and Space Sciences, volume 6, issue 1, 1989, Pages 57~72
A total of 80 photographs on 29 nights and another total of 44(22 each in B and V) photoelectric observations on 6 nights are secured for P/Halley(1982 ⅰ) for seven months before and after the perihelion passage. The photographic observations have been mode at different places depending on the position of the comet and the development of the tail, while the photoelectric observations were made only with 61-cm reflector at Yonsei University Observatory(YUO). Four most representative photographs are presented only to illustrate the remarkable features of the comet. The second one of these shows a coma with a possible flash activity on 1985 SEPT. 18.56 UT. The third one shows the largest tail recorded among our plates, and the last one prepresents unusual record made on northern hemisphere at a latitude as high as about
12' N on the occasion of the comet's second perigee on 1976 APR. 11.6 UT. Photoelectric observations, on the other hand, determine the V and B-V of the total and the coma of the comet before its perihelion passage, and exhibit the light variations of 0m.6 in V in an hour and a half. Two new sets of m and n, one before and the other after the perihelion passage, determined based on the collected data, but the values are dissimilar one another significantly.