空间科学学报

1986 Vol. 6, No. 2

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Stabilities of Rotational Discontinuity for Magnetopause

Wang Shui, Zhu Lie, Fan Xiao-ying

1986, 6(2): 89-96. doi: 10.11728/cjss1986.02.089

Abstract(1549) PDF 487KB(606)

Abstract:
In this paper, by using a three-layer model and the observations from Satellite ISEE, the stabilities of rotational discontinuity for magnetopause are discussed. The results show that: (1) a kind of instability may be excited in the magnetopause rotational discontinuity, the growth rate of the instability increases as the wave number k increases; (2) when the interplanetary magnetic field is northward, the magaaetopause rotational discontinuity is stable; when the interplanetary magnetic field becomes southward gradually, the growth rate of the instability increase rapidly; (3) when the velocity of solar wind is larger, the growth of rate of instability is larger correspon-dently; (4) when the interplanetary magnetic field is southward, the growth rate of instability increases rapidly as the angle between the interplanetary magnetic field and the tangential surface of the magnetopause increases.

Some Statistical Results about the Energetic Particle Pulses in the Magnetotail

Wu Ji-ping

1986, 6(2): 97-101. doi: 10.11728/cjss1986.02.097

Abstract(1497) PDF 386KB(856)

Abstract:
This paper presents the results of correlation analysis between the data of energetic particle pulses obtained by IMP-Jspacecraft (P4: 230keV>E>160keV) and auroral electrojet index AE. The magnetotail is devided into three regions: neutral sheet region, low latitude region and high latitude region. It is found that: (1) In the neutral sheet region, the average energetic particle fluxes is the highest among all three regions. In the high latitude region the fluxes is the lowest. This indicates that the "source" of energetic particle pulses may be located in the neatral sheet region. (2) The correlation between energetic particle pulses and AEindex is most significant in the neutral sheet region, the correlation coefficient Ris 0.59. In low and high latitude region, Rdecreases sharply. It coincide with the idea that energetic particle pulses event is substorm relevant event, the particles are accelerated by induced electric field caused by magnetic field line reconnection near the neutral sheet region. (3) Accelerated area is limited to a thin layer around neutral sheet, it coincides with Hones results.

Effects of Non-radial Geomagnetic Field Lines on Evaluating Ionospheric Fields and Three-dimensional Current System from Ground Magnetic Data

Gu Shi-fen, Tian Bao-ning, Song Li

1986, 6(2): 102-111. doi: 10.11728/cjss1986.02.102

Abstract(1440) PDF 565KB(885)

Abstract:
Some improvements are made to the method developed by Kamide (KRM method) in evaluating ionospheric electric field, current and field-aligned currents from ground variations. Taking into account the effects of non-radial geomagnetic field lines on the ionospheric conductivity, a second-order partial differential equation for electric potential is rederived, which will come back to the original form of Kamide's equation when inclination equals to 90°.To show the effects of this improvement, an example is given and the results show a considerable effect of the non-radial field lines even in high latitude auroral regions. At magnetic latitude 67°, the correction by the improvement can be up to 21% for ionospheric current, and up to 10% (4kV) for electric potential. Finally, in this example, the rate of convergence in the iterative procedure increases, too, from 300 times to only 202 times.

Decomposition Kinetics of Low Density Ablative Materials

Liu Jin-xiang, Gao Xiu-ying

1986, 6(2): 112-117. doi: 10.11728/cjss1986.02.112

Abstract(1352) PDF 356KB(641)

Abstract:
The decomposition kinetics of three low density ablative materials are studied by means of TG. The method of Broido is applied to treat TGdata in order to obtain kinetic parameters from thermal analysis curves. By checking with CaCO₃ samples of known decomposition kinetic parameters, the results obtained are found to be in agreement with those from the literature, and differences in activation energy are less than 0.25%. The decomposition kinetic parameters of three low density ablative materials using the Broido method are obtained.

The Motion of Metter in Flare Loops on Solar Disc

Xu Ao-ao

1986, 6(2): 118-122. doi: 10.11728/cjss1986.02.118

Abstract(1506) PDF 345KB(917)

Abstract:
The motion law of matter in flare loops on solar disc is discussed by using the optical observational data of the two-ribbon flare in July 14, 1980 obtained at Yunan Observatory and X-ray data of same flare from SMM. Firstly, the comparison of positions between Ha and X-ray images is used to estimate the altitude of the flare loop. Secondly, the sight-line velocity field of the flare is theoretically calculated for matter falling in flare loops, the theoretical results agree with observational data on the whole.

The Corotating Variation of Heliospheric Quantities (II)——Evolutions in the Solar Cycle 20

Zhang Gong-liang, Gao Yu-fen, Lu Chen, Xu Yuan-fang

1986, 6(2): 123-129. doi: 10.11728/cjss1986.02.123

Abstract(1314) PDF 454KB(909)

Abstract:
The evolutions of corotating variation of some basic heliospheric parameters and energy parameters are studied in this paper for the solar cycle 20. It is shown that the ascending-phase single-peak distribution of solar wind velocity in the carrington rotation changes through the multi-peak one in the solar maximum into the stable two-peak ones in the descending and minimum phases. The number density, however, has always displayed a two-peak distribution since the solar maximum. Also shown in the statistical curves for both the ascending and descending phases is the exsistence of corotating compression disturbances with a marked enhancement of various densities and flux densities but without significant change in the velocity.

The Sodium Atom Coma of Comet Bennett (1970II)

Hu Zhong-wei, Che Hao

1986, 6(2): 130-136. doi: 10.11728/cjss1986.02.130

Abstract(1629) PDF 484KB(851)

Abstract:
In this paper, the sodium atom coma of comet Bennett (1970II) is analysed. Using the Na-Dmonochromatic isophotes given by Rahe, average scale-lengths of sodium atom and its parent molecule are found by Haser's theoretic model. Converting to heliocentric distance 1 AU, they are 4.49×10⁵ km and 1.47×10⁴ km respectively. Taking typical outflow velocity, mean lifetimes of sodium atom and its parent molecule are estimated as 1.5×10⁵ seconds and 2.45×10⁴ seconds respectively. With the use of theoretic formula of Dolginov as well as other related formula and data, it is calculated that the thermal velocity and temperature of sodium atom are respectively as 2.04-5.69 km/s and 5.76×10³-4.48×10⁴ K, and hydrodynamical (outflow) velocity of sodium atom is 2.66X10 km/s when converting to heliocentric distance 1AU. Finaly, brief discussions on relevant problems are also made.

The Influence of the Great Solar Flare of 24 April 1984 on the Ionospheric Total Electron Content

Ma Jian-min, Long Qi-li

1986, 6(2): 137-142. doi: 10.11728/cjss1986.02.137

Abstract(1611) PDF 577KB(995)

Abstract:
Sudden increases of the ionospheric total electron content (TEC) during the great solar flare burst near 2356 UTon 24 April 1984 were simultaneously observed at Xin-xiang (35.3°N, 113.9°E) and Chongqing(29.5°N, 106.4°E) by means of Faraday rotation measurements of the VHFsignals from the Japanese geostationary satellite ETS-II. These sudden increases lasted three and a half minutes, and the values of TECincreases at Xinxiang and Chongqing reached 9.4×10¹⁶ and 14.3×10¹⁶ ele./m² respectively. The phenomenon recorded by polarimeters is compared with results from neighbouring ionosondes and VLF phase-locked receiver. The analysis shows that there are appreciable increases of electron density both in the ionospheric D-region and the F-region and the latter is the main part of the sharp TEC increases.

A Test of International Reference Ionosphere IRI-79 Using Ionospheric Electron Content Data

Dai Yue-qin

1986, 6(2): 143-146. doi: 10.11728/cjss1986.02.143

Abstract(1490) PDF 274KB(938)

Abstract:
Acomparison is made between the ionospheric electron content measured at Xian in 1978-1979 and that calculated from International Reference Ionosphere IRI-79. It is shown that the electron content calculated from IRI-79 in spring is much lower and this could be due to the too low electron density of the IRImodel above the F₂ peak level.

Some Observation Results of the Radiation Belt Electrons from Satellite Borne Semiconductor Telescope

Cheng Dong-yuan, Wu Ji-ping

1986, 6(2): 147-151. doi: 10.11728/cjss1986.02.147

Abstract(1458) PDF 307KB(771)

Abstract:
By analysis the observation data from the instruments on board of Chinese satellites, the typical omnidirectional fluxes of inner belt electrons with energy higher than 0.5 MeV and 1.0 MeV as 1.9×10⁸ and 6.7×10⁷ele./s.cm² respectively are obtained. Aprofile of electron flux on a typical orbit is also given. In addition, the omnidirectional fluxes with the same energy ranges at the synchronous altitude obtained from the first Chinese geostationary satellite are 2.43×10⁶ and 4.25×10⁵ ele/s.cm² respectively. At the same time, the diurnal variations of electron flux of outer radiation belt are also given and they are essentially agreeable with the observations made abroad.

Design and Construction of High Precision Prism Sun Sensor

Xiao Gong-bi, Xu De-yang

1986, 6(2): 152-157. doi: 10.11728/cjss1986.02.152

Abstract(1494) PDF 405KB(922)

Abstract:
In carrying out a project of developing an astronomical satellite, a prototype of high precision prism sun sensor was designed and constructed. The principle of prism solar positoin measurement is proposed. By this principle and some methods such as energy balance measurement, compensation of the variation of irradiance etc., a high precision measurement of solar position is realizable. Asun sensor designed on this principle has a high resolution and precision in small view fields, a small size, a light weight and a long service life. According to the conclusion of a formal evaluation, such an instrument has a resolution of 1" and a precision of ±3" in a view field of ±70'. The entire system weighs 2.5 kg, requires 1 watt of power consumption.

POWERFUL RADAR PROBING OF THE ATMOSPHERE

Chen Pei-ren

1986, 6(2): 158-167. doi: 10.11728/cjss1986.02.158

Abstract(1489) PDF 731KB(808)

Abstract:
Areview of the principal aspect of the powerful radar (Incoherent Scatter Radar and MSTradar) probing of the atmosphere is given. Both the developments of sounding technique and main results are presented.