空间科学学报

1996 Vol. 16, No. 2

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THE POSITION OF PARTICLE SOURCE IN SOLAR ELECTRON EVENTS

Wang Xue-yi, Huang Yong-nain

1996, 16(2): 85-91. doi: 10.11728/cjss1996.02.085

Abstract(2041) PDF 436KB(878)

Abstract:
In this paper, the ISEE-3 energetic particle data from 51 solar electron events are analysed. And the equilibrium temperature of Fe-rich events and Fe-poor events are calculated based on the model. The source position of particles in the Ferich events is found to be in the high-chromosphere, while the source position of particles in the Fe-poor events in the region between the chromosphere and the corona. The source positions of particles in both the Fe-rich events and Fepoor events are found to be always different from their corresponding flare regions. According to above results, the processes of formation for the two types of electron events are proposed.

A Sun-ALFVENIC FLOW IN THE STRONG INTERPLANETARY MAGNETIC FIELD STRUCTURE

Zhang GOng-liang

1996, 16(2): 92-96. doi: 10.11728/cjss1996.02.092

Abstract(2208) PDF 2458KB(1038)

Abstract:
On November 23, 1982, an extremely high-speed stream was overtaking a strong magnetic field structure, resulting in an interplanetary combinative structire including high-density front sheath, main part with strong magnetic field and low density, high density rear sheath, and extremely high-speed streams. The MHD characteristics of the combinative structure are analyzed in this paper. A sub-Alfvenic flow is found inside the main part of the strong magnetic field structure, the formation of which is also discussed.

THE MOVING RADIATION OF COSMIC MAGNETIC MONOPOLE IN ELLIPTIC ORBIT IN PLASMA

Ma Shan-jun, Yang Qian-li, Luo Kai-ji

1996, 16(2): 97-102. doi: 10.11728/cjss1996.02.097

Abstract(1833) PDF 356KB(1270)

Abstract:
In thes paper, the radiation of the cosmic magnetic monopoles which move in a elliptic orbit in cosmic space are studied. A formula of the radiant spectrum power is de rived. The formula could be used to detect and distinguish the existence of cosmic magne tic monopole.

DUCT PROPAGATION OF VERY LOW-LATITUDE WHISTLERS

Tu Jian-nan, Liu Zhang-qing, Bao Zong-di

1996, 16(2): 103-108. doi: 10.11728/cjss1996.02.103

Abstract(2045) PDF 468KB(644)

Abstract:
The propagation mechanism of very-low latitude whistlers is discussed. On the basis of characteristics of low-latitude whistlers, the diffusive and multi-hop whistlers during magnetic storms are thought to propagate along the paths of field-aligned ionization enhancements resultal from a disturbed eastward electric field. The simulation of low-latitude F region in the presence of a eastward electric field shows that the field-aligned ionization enhancements is a favourable condition for trapping and propagation of whistlers.

THE EFFECT OF ASTEROID IMPACTS IN CENOZOIC ON PALEOCLIMATE AND CARBON CYCLE

Xiao Zhi-feng, Ouyang Zi-yuan, Lin Wen-zhu

1996, 16(2): 109-114. doi: 10.11728/cjss1996.02.109

Abstract(2274) PDF 440KB(1103)

Abstract:
The paleoclimate effects of six asteroid impact events on the Earth happened in Cenozoic are studied by employing a energy-balance model. The result shows that when the dusts produced by these impacts entered the stratosphere, the average temperature of the Earth decrease to below 0℃, the disturbances caused by the impacts on temperature are last for about 30 years in maximum. It is first time that greenhouse effect of the carbon diozide produced by global fire and decomposition the died animals and plants is considered in modeling. However, at maximum, carbon dioxide produced by these two effects (global fire and decomposition of the died animals and plains) only makes an increase of 67% the atmospheric carbon dioxide, the greenhouse effect is so small that it can be negleted while compared with the effect of the antigreenhouse effect of the dusts. When the global carbon cycle is considered,these two effects on atmospheric carbon dioxide are last for 100 years.

THREE CLASSES OF PROTON FLARES

Lin Hua-an

1996, 16(2): 115-121. doi: 10.11728/cjss1996.02.115

Abstract(2454) PDF 459KB(1006)

Abstract:
The nuclear γ-ray line (GRL) and the proton event (PE) observed in interplanetary space are direct evidences that protons and heavy ions are accelerated to energies above several MeV per nucleon for solar proton flares。 Solar Hard X--ray properties obtained by SMM satellite show there are three classes of solar proton flares: GRL, PE and GRL/PE。 The results indicate the different behavours respect to the hard X--ray properties for the three classes of proton flares seem to be relative with the different height distribution of energetic particles acceleration region (or active region) for the GRL, PE and GRL/PE proton flares。

THE EFFECT OF GEOMAGNETIC STORM ON VLF EMISSION AT CLEFT LATITUDES

Liao Huai-zhe

1996, 16(2): 122-127. doi: 10.11728/cjss1996.02.122

Abstract(2265) PDF 412KB(853)

Abstract:
A statistical has been carried out for the relationship between the VLF activities at dayside cleft latitudes and geomagnetic storms from Apr. 1984 to Feb. 1987. It is shown that: 1. There is an obvious effect of geomagnetic storm on the VLF emissions. 2. The VLF emission activities are affected by geomagnetic storms in a way that.there are an obvious VLF activity decrease before or during storm onset day anda large increase of the activities after geomagnetic storm. 3. The influence of Sc storm on VLF activity is different from that of Gc storm. 4. There is a characteristic seasonnal asymmetry of the effects. In local winter the VLF decrease during Sc storm onset day and the VLF increase after G. storm reaches mazimum, while in summer the decrease and the increase are small. The amplitude of the decrease and the increase in winter is 3 times as large as in summer.

THE EFFECT OF IMF By ON THE MLT DISTRIBUTION OF THE OCCURRENCE OF VLF HISS

Tian Bao-ning

1996, 16(2): 128-132. doi: 10.11728/cjss1996.02.128

Abstract(2238) PDF 312KB(606)

Abstract:
The effect of the interplanetary magnetic field dawn-dusk component (IMF B_y) on the MLT distribution of VLF hiss occurrence is analysed in this paper by using 31-38kHz VLF data observed at the south pole station (invarent latitude about 75°). It is foUnd that IMF B_y influnces the distribution of the VLF occurrence stronly, especially at the day side. The asymmytry of VLF occurrence at pre-noon MLT region and at post-noon MLT region at cusp latitude exists.The peak of the VLF occurrence is much more higher at post-noon sector than at pre-noon sector when positive B_y but the peak of VLF occurrence at postnoon becomes bigger when is negative B_y. This B_y control is related to the B_y control of magnetospheric plasma convection patterns and the distribution of electrons precipitation.

THE TEC VARIATIONS DURING SUDDEN MAGNETIC STORM IN WUHAN

Li Li-bin, Wu Zhen-hua, Wang Bing-kang

1996, 16(2): 133-139. doi: 10.11728/cjss1996.02.133

Abstract(2202) PDF 2595KB(1164)

Abstract:
In this paper, 136 sets of Faraday rotation data obtained by observation of Japanese Geostationary satellite ETS--Ⅱ radio beacon during April 1980 to December 1990 at Wuhan are analysed to study the response of TEC to SC Geomagnetic storm. It was found that TEC generally enhances during geomagnetic storm. The behavior of △TEC shows much disparity from that observed at mid--and high--latitude. Another interesting fact was that if SC starts in daytime, △TEC will get maximum 36 hours later. Otherwise, no maximum of △TEC appears. This fact exists all the time regardless of sunspot number or season.

THE RELATIONSHIP BETWEEN FIELD-ALIGNED CURRENT AND SUBSTORM PHASE

Jiao Wei-xin.

1996, 16(2): 140-144. doi: 10.11728/cjss1996.02.140

Abstract(2536) PDF 345KB(1345)

Abstract:
ISEE 1 and 2 measurements of magnetic changes across nightside fieldaligned currents (FACs) in the inner magnetosphere are examined to determine the average ionospheric extrapolated characteristics and properties of regin 1 and 2 currents as a function of substorm phase. The properties of these currents studied include current intensity, density and layer width. It is found that there is a close relation between FACs and substorm phase. Both region 1 and region 2 currents intensity reach their peak during the expansion phase. The average value of intensity in region 1 is about 1.4 times greater in region 2. The current densities in region 1 and 2 behave same with current intensity, i.e from the growth phase to expansion phase, the density increases and from the expansion phase to the recovery phase it decreases.

RESPONSE OF MESOSPHERIC OZONE TO THE 27-DAY SOLAR ULTRAVIOLET VARIATIONS

Xu Ji-yao, Zhao hong-hu, Wang Ying-jian

1996, 16(2): 145-151. doi: 10.11728/cjss1996.02.145

Abstract(2222) PDF 430KB(948)

Abstract:
A series of studies are preformed concerning the response of mesospheric ozone to the 27-day solar ultlaviolet variations. The studies are bed on SME 1982--1983 solar ultraviolet data and 50--90km equatorial infrared ozone data. A theoretical computation is presented by using atmospheric photochemical wave model. The calculated result is nearly in agreement with that of observations.

STATISTICAL CHARACTERISTICS OF INERTIAL GRAVITY WAVES OBSERVED BY VHF RADAR IN THE POLAR MESOSPHERE

Zhang Shao-dong, Yi Fan, J' Klostermeyer, R. Ruster

1996, 16(2): 152-158. doi: 10.11728/cjss1996.02.152

Abstract(2140) PDF 438KB(878)

Abstract:
This paper statistically investigates the propagation characteristics of inertial gravity waves in the mesorphere with VHF radar observations at Andφya(69°N, 10°E) Norway from June 22 to June 29 1987. It is found from the observations that 21 wave examples are of good monochromaticity and have certain certical progressions of phase.Their periods are severel home, indicating they are medal internal gravity waves. The distribution of horizontal wave vectors is extimated by analysing the hodographs of wave-asspcoated horizontal fluid velocity, most (76%) of them propagate westward, it seems to be related to the intense westward background wind at mesopause, The estimated horizontal wave vectors are the typical values observed in mesosphere. There are 15 (6) examples with downward (upward) phase progressions among the 21 examples. Their vertical wave lengths range from 5 to 9 km, wave-associated velocities are from 10 to 50m/s,indicating there exists not only upward but also intense downward wave energy flux in the polar mesosphere.

EVALUATION OF TEC FROM NNSS SATELLITES DATA

Ma An-xin, Cheng Yan-ming

1996, 16(2): 159-166. doi: 10.11728/cjss1996.02.159

Abstract(2070) PDF 590KB(589)

Abstract:
In this paper, a method to improve the determination of Total Electron Content (TEC) using the measured differental data of NNSS satellites in a large range above a station is presented' At the same time, several measured and calculated results are analysed qualitatively and quantitatively. The diurnal TEC change curves can be given at a large range of positions above a station.