空间科学学报

1997 Vol. 17, No. 2

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NUMERICAL SIMULATION OF MAGNETIC CLOUDHIGHSPEED STREAM INTERACTION

HU Youqiu, CHEN Jian, ZHANG Gongliang

1997, 17(2): 97-103. doi: 10.11728/cjss1997.02.097

Abstract(2070) PDF 463KB(818)

Abstract:
A numerical simulation is carried out on the interaction between the magnetic cloud and the follow-up highspeed stream observed at 1 AU August 27 - 28,1978, and it basically reproduces the observed profiles. The numerical results show that the magnetic cloud - highspeed stream system leads to the formation of a forward fast and slow shock as well as a reverse fast shock. The forward fast and slow shocks originate from the magnetic cloud whereas the reverse fast shock is generated by the highspeed stream. However, the properties of these shocks have been affected by the interaction between the magnetic cloud and the high speed stream in various degrees. Under the pursuit of the highspeed stream, the magnetic cloud is restrained from expansion at its tail part, where a structure of high temperature, high density and strong magnetic field is formed.

THE EVOLUTION OF NONLINEAR KINETIC ALFVEN WAVES

WANG Deyu, WEI Fengsi, SONG Liting

1997, 17(2): 104-109. doi: 10.11728/cjss1997.02.104

Abstract(2193) PDF 383KB(932)

Abstract:
Some restriction conditions of soliton solution for a nonlinear kinetic Alfven wave in the case of me/ mi<< β<< 1 have been discussed in detail. It is found that a compressive soliton can form only in the subAlfven velocity. The maximum parallel electron velocity, induced from kinetic Alfven soliton and turbulenee cannot exceed the thermal velocity of background electrons, but its maximum parallel electric field mny rather strong in the small scale region. It will produce a certain influence for energy transfering and particle acceleration in the solar wind'

DIMENSIONLESS JUMP CONDITIONS FOR THE MHD SHOCK WAVES IN AN ANISOTROPIC PLASMA

LU Jianyong, WEI Fengsi, FEI Zhenyong

1997, 17(2): 110-107. doi: 10.11728/cjss1997.02.110

Abstract(1881) PDF 422KB(925)

Abstract:
The jump relations of the MHD shock wave in an anisotropic plasma are investigated by using the dimensionless method, and the general shock solutons can be obtained when the anisotropic coefficient is known. The jump relations undr the assumption of isotropy are also discussed and compared with the previous results.

ELECTROMAGNETIC INSTABILITY PRODUCED BY SOLAR ELECTRON BEAM THROUGH LONGITUDINAL FIELD WITH OSCILLATION

WANG Xueyi, YI Rong, XU Yonghong, HUANG Yongnian

1997, 17(2): 118-123. doi: 10.11728/cjss1997.02.118

Abstract(2089) PDF 471KB(1075)

Abstract:
A model on the interactions of relativistic electrons and magnetic field with space oscillation is put forward based on the observational characteristics of solar highenergy electrons and opened magnetic field in corona and in interplanetary medium.Numerical method is used to study R-mode cyclotron electromagnetic instability which is excited by electron beam going through longitudinal field wiih space oscillation, when some initial conditions are satisfied such as the velocity of beam and the wave number of oscillation field. The electromagnetic wave with low-frequency drift may be excited when solar high-energy electrons pass through corona and interplanetary medium.

ANALYSES AND FEATURE OF MHD WAVES IN TYPE-Ⅰ COMETARY TAILS

LI Zhongyuan, SHI Zhidong, GU Shunyong, CHENG Zongyi, TONG Yi

1997, 17(2): 124-129. doi: 10.11728/cjss1997.02.124

Abstract(2175) PDF 407KB(715)

Abstract:
In this paper, the dispersion relation of MHD waves is analysed for Type-Ⅰcometary tails. The instability of helical waves and its evolution features are studied.In terms of different initial conditions, stable helical waves or irregular clouds may exist in different cometary tails. There is a good consistence between theoretical deduction and observational records. Further research for comet Hale-Bopp may be done based on this work.

MODELING STUDY OF MODIFICATION OF THE LOWER IONOSPHERE BY VLF ELECTROMAGNETIC WAVES

LIU Libo, WU Xiangyang, TU Jiannan, Bao Zongti

1997, 17(2): 130-135. doi: 10.11728/cjss1997.02.130

Abstract(2107) PDF 452KB(1109)

Abstract:
Using a complicated model which consists of the lower ionospheric heating by VLF electromagenetic waves a model and a night-time D region chendstry model,ttos paper studies heating effects under the innuence of parameters of neutrals and reaction coefficients of D region chemistry The results indicate that heating effects are strongly dependent on parameters of neutrals and reaction coefficients of D region chemistry.

THE MAGNETOSPHERE-IONOSPHERE COUPLING EFFECT DURING THE STORM OF 12-14,SEPT.1993

SHEN Changshou, ZI Minyun, GAO Yufen, WU Jian, SUO Yucheng

1997, 17(2): 136-141. doi: 10.11728/cjss1997.02.136

Abstract(1660) PDF 301KB(1041)

Abstract:
The geomagnetic indias, such as the ring current inflation rate, the aurora electrojet indices AU AL and the mid-latitude geomagnetic index ASY-H and the geomagnetic H-and Z-componen, the ionospheric data f₀F₂ and h'F observed in China, are used for analysing the evolution of disturbed ionospheric current and electric field during a typical storm. It is shown that the geomagnetic indices and observed parameters can reflect the main features of the magnetosphere -ionosphere coupling.

A MODEL STUDY OF THE STORM-TIME BEHAVIOUR FOR MID-LATTTUDE IONOSPHERE

ZHANG Shunrong, HUANG Xinyu

1997, 17(2): 142-148. doi: 10.11728/cjss1997.02.142

Abstract(1774) PDF 487KB(995)

Abstract:
This paper introduces a new method of the theoretical modeling and simulation of the ionospheric storm behaviour in mid-latitudes, with the use of the experimental ionospheric data. The effects of the atom-molecule ratio, topside fluxes and neutral winds on the ionospheric structure are discssed for the two very different storm events. It is found that, neutral winds vary shadily during the events, while the relativer importance of the ratio is distinct in each event, and the fiuxes differ also. There suggest that the ionosp heric behavioar in the storm time has many dependencies, which can only be determined by the concrete solar-geophysical and atmosphyeric background conditions.

OBSERVATIONS OF SPECTRUM OF VERTICAL VELOCITY FLUCTUATIONS AT HEIGHTS OF 70-100 km IN POLAR SUMMER

WU Yongfu

1997, 17(2): 149-154. doi: 10.11728/cjss1997.02.149

Abstract(2003) PDF 434KB(991)

Abstract:
Vertical wavenumber spectrum of vertical velocity fluctuations of atmosphere at heights of 70 - 100km is presented using vertical velocity data obtained from five chaff rocket measurements carried out during the MAC /SINE campaign in the summer of 1987 at Andenes, in Northern Norway (69°N, 16°E). The atmospheric vdrical wavenumber spectrum of the vertical velocity has a spectral gap at m=3.9×10^-4m^-1. At vertical wavenumbers greater than the spectral gap the vertical wavenumber spectrum agerees well with the saturated spectrum model. At vertieal wavenumbers smaller than the spectrla gap the vertical wavenumber spectrum has a slope of - 1.87 and a spectral amplitude that is an oder of magnitude lower than the saturated spectrum, suggesting that other geophysical processes besides gravity waves'may exist in the verticla velocity fluctuations.

THE OBSERVATION OF WIND FILTERED IONOSPHERIC GRAVITY WAVES

YUAN Hong, WAN Weixing, LIANG Jun

1997, 17(2): 155-158. doi: 10.11728/cjss1997.02.155

Abstract(1871) PDF 280KB(1103)

Abstract:
This paper analyses the drift data of the digisonde (DGS-256) at Millstone Hill (288.5°E, 42.6°N ) The result shows that the propagation direction of ionospheric gravity wave disturbances rotates clockwise throughout the day, the maximum of the disturbances occurrence is at the angles between 180°and 225° reative to the caiculated direction of background wind. Evidentiy, the result implies that disturbanas are wind filtered. Further analysis shows that the smaller the disturbance's scale, the more obvious it propagathe on the opposite direction of wind.

E-P FLUX DIAGNOSIS FOR CROSS-EQUATOR PROPAGATION OF LARGE-SCALE PLANETARY WAVES

ZHANG Feng, MA Ruiping, MU Xiangming

1997, 17(2): 159-165. doi: 10.11728/cjss1997.02.159

Abstract(2046) PDF 432KB(996)

Abstract:
Using Ndrius-7 sateilite grid temperature data, the mean wind and gcopotential disturbution are caiculated and E-P flux are analysed in stratosphere and mesosphere.The results show that the stationary part of the quasi-stationary plancetary waves in middle atmosphere may not propagate across the zero wind line. The transient planeary waves are stimulated due to the amplitude fluctuation and phase variation of the quasi stationary planetary waves. They are not confined by the an wind line and can propagate across the Nuator from winter-hemisphere to summer-hemisphere or from summer-hemisphere to winter-hemisphere. The cross-equator propagation provide an explanation for the energy source of the planetary waves in summer hemisphere.

FEASIBILITY OF RETRIEVING MESOSPHERIC OZ0NE FROM TWILIGHT AIRGLOW

WANG Yingjian, LU Yong

1997, 17(2): 166-171. doi: 10.11728/cjss1997.02.166

Abstract(1842) PDF 377KB(952)

Abstract:
Rerieving atmospheric ozone using 1.27μm twilight airglow is an important method of mesospheric atmospheric ozone measurements. In this paper, the information content,measurable height and venical resolution have been studied, and the effect of the uncertainty of photocheemical and atmospheric models parameters and the sensitivity of the variation in mesospheric ozone content have been discussed. The numerical simulation results show that the atmospheric ozone content in 60-9Okm altitude may be given using 1.27μm twilight airglow measurements, the effect of the uncertainty of photochemical model parameters is about 1O%.

THE SELECTION OF REAR SHAPES OF PRIMARY MIRRORS IN SPATIAL OPTICAL REMOTE SENSOR

WU Qngwen, LU'E, WANG Jiaqi, XU Biao

1997, 17(2): 172-177. doi: 10.11728/cjss1997.02.172

Abstract(1998) PDF 471KB(1369)

Abstract:
The necessity of using lightweight primary mirror in spatial optical remote sensor is statal in this paper. The suffoce figure of primary mirrors in shapes of double-concave,plain-rear, single-arch and double-areh is computal, Which works out a conclusion that double-concave mirror is the best one, supported in three-point pattern The regularity of wave front error (RMS value) vs. normalized radius r / R is studied, which indicates that the best support radius is 0.74

STATISTICAL RELATIONS BETWEEN SUN SPOTS AND DISEASES

MA Yuehua, SONG Yi

1997, 17(2): 178-183. doi: 10.11728/cjss1997.02.178

Abstract(2020) PDF 372KB(1103)

Abstract:
In this papcr, the relationship bbe solar activities and diseases is investigatal by using observed data of solar actvities and stahstical data of diseases in Epidemic Prevenlion Station of Jiangsu Province in 22 years, the curves for reative ratio of various diseases and the reative number of sun spots with time are drawn, and their reatal coeffidents are calculated'The results show that there are some reations between solar activities and the inddences of anrle fever, hepatitis and polio, especially the anrlet fever,Whose correation coefficient is as high as 0.72.

A MECHANISM FOR THE NON-GYROTROPIC DISTRIBUTION OF THE SOLAR WIND PARTICLES

TU Chuanyi, LI Chunqiang

1997, 17(2): 184-188. doi: 10.11728/cjss1997.02.184

Abstract(1728) PDF 319KB(857)

Abstract:
It is suggested in this paper that the non-gyrotropic particle velocity distributions may not represent the real distribution of the particles. It may be resulted by a sudden changes of density during the sampling period of the plasma analyar for a single velocity distribution. Simulation results based on this idea are qualitatively agree with the observations.

PHASE SPACE RECONSTRUCTION OF MAGNETOSPHERE FROM AE INDEX──DISCUSSION OF THE PROBLEMS EXISTED

GAO Yufen, ZHOU Rongmao, YANG Dongmei

1997, 17(2): 189-192. doi: 10.11728/cjss1997.02.189

Abstract(1892) PDF 349KB(935)

Abstract:
It is short of dear evidences for judging whether the magnetosphere is a deterministic nonlinear system from correlation dimensions, which are computed from AE index by phase space reconstruction. This is because AE index can not correctly reflect geomagnetic adivities with various different levels. So AE index is not an ideal index for phase space reconstruction of magncetosphere.