空间科学学报

1997 Vol. 17, No. 1

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INTERACTION BETWEEN FLARE-INDUCED SHOCKS

XIA Lidong, HU Youqiu

1997, 17(1): 1-15. doi: 10.11728/cjss1997.01.001

Abstract(2063) PDF 342KB(877)

Abstract:
The interaction between two consecutive flare-induced shocks is discussed using a one-dimensional MHD model and the shock fitting method' The rarefaction waves appearing in the downstream region of the leading shock change the property of the tailing shock remarkably, and generates a strong reverse fast shock downstream it. The merging of the two flare-induced shocks leads to the formation of a contact surface, of which the density ratio is about 1.5.

NUMERICAL SIMULATION OF FLARE-INDUCED SHOCK WAVES

HU You-qiu, XIA Li-dong

1997, 17(1): 7-13. doi: 10.11728/cjss1997.01.007

Abstract(1906) PDF 464KB(910)

Abstract:
Using a one-dimensional MHD model and the shock fithng method (SFM), this paper discusses the propagation of flare-indutal shocks and the assodated wave structure downstream. It is shown that in the downstream region a rarefaction wave systo fonns, consishng of a fast rarefachon wave pair, and a reverse slow rarefaction wave and an entropy wave-like structure sandwiched in it. The same problem is also treated by the shock capturing method (SCM). It is concluded by comparison that the SCM cannot provide a reliable and a qualitahvely acceptible description of the propagation of flare-indued shocks in the interplanetary space, whereas the SFM seems to be the only prondsing choice.

KINETIC ALFVEN SHOCK IN THE SOLAR WIND

LU Xianhe, SONG Liting, WEI Fengsi

1997, 17(1): 14-19. doi: 10.11728/cjss1997.01.014

Abstract(2376) PDF 370KB(1160)

Abstract:
In this paper, a theory of kinetic Alfvenic shock wave in the solar wind is presented. There ekist nonlinear interaction and dispersion in the kinetic Alfven wave regime. Thus, theoretically the kinetic Alfven shock wave can occur. Based on this idea, a two fluld model combined with the abnormal damping of ion acoustic wave is considered, and then the inunediate shock structure is obtained by numerical simulation.

2-DIMENSIONAL STRUCTURE OF SOLAR WIND SPEED ON THE SOURCE SURFACE

LU Hong, WEI Fengsi, ZHOU Qingiun

1997, 17(1): 20-24. doi: 10.11728/cjss1997.01.020

Abstract(2593) PDF 319KB(655)

Abstract:
The solar wind speed structure on the source surface is studied on the basis of IPS data in the year of l984 during Carrington rotation l745- l755' IN the mapping-back processes, the influence of acceleration on the foot point of the Archimedian spiral and the values of solar wind speed are considered. The results is compared with the map determined by the MHD model which uses the K-coronal brightness and photospheric magnetic field as inputing condition. This results are also compared with that from the other authors. The comparison shows that: the MHD model can preliminarily work out the 2-D structure of solar wind; and the decrescent amplitude and width of the low-speed belt seems to imply the ekistence of a latitudinal direction stream.

ANALYTICAL SOLITARY SOLUTIONS TO DNLS EQUATION WITH DAMPING AND DISPERSION

FENG Xueshang, LU Jiangyong

1997, 17(1): 25-31. doi: 10.11728/cjss1997.01.025

Abstract(2096) PDF 369KB(1006)

Abstract:
In this paper, a method of variable changes and numerical integral is employed to obtain the analytical solutions with shock layer structures for the DNLS equation by considering Ohm's resistance' Based on the explict solutions, the effect of dispersion on the amplitude and magnetic flelds B_y, B_z is discussed. The results show that the dispersion has an obvious control over the shock width: the smaller the dispersion, the larger the shock width and slower the B_y B_z decay. When the dispersion is small enough, B_y, and B_z turn into pure solitons. In case of no dispersion, the solitary solution with a modulating factor is also obtained.

A TRANSIENT PROCESS IN THE AURORAL ELECTROJET

WANG Jingsong, CHEN Zuxing, YAN Xiaoyang

1997, 17(1): 32-36. doi: 10.11728/cjss1997.01.032

Abstract(2245) PDF 367KB(1067)

Abstract:
In this paper, the building prare of the auroral electrojet was analytal and it was consided that there is a posihve feedback, therefore a transient process during the building pedod' To probe the physics mecanism, a simple model was utal in this paper to sdriulate the building of the auroral electrojet. The results show that there does be a transient process in the auroral electrojet. The structure along the eleCtrojet of curmt, net charge or conductivity is a propagahng jump, whereas the elecric field kaps neariy invariable.The calculatal results agree to the observahons rather well.

THE EVOLUTION OF FILAMENT CURRENT AND SOURCES OF FLARE ENERGY

CHEN Xiezhen, YIN Chunlin

1997, 17(1): 37-42. doi: 10.11728/cjss1997.01.037

Abstract(2252) PDF 394KB(901)

Abstract:
Using the optical data of two active regions, the dynamical evolution of two filaments associated with two kinds of solar flares are analysed The results show that the mutual actions between arch filament and background rnagnetic field could lead to trigger of energtic flares, and the activation of quiescent filaments are always associated with lower energy flares.

ON ACTIVATION OF TWO ARCH-LIKE FILAMENTS 0F FEBRUARY 4, 1986

YIN Chunlin, TANG Yuhua

1997, 17(1): 43-48. doi: 10.11728/cjss1997.01.043

Abstract(2253) PDF 433KB(838)

Abstract:
Using observational data, the images in Ha and white light and the vector magnctogram, the dynamical behaviour of two arch-like filaments in AR47/11 on February 4, l986 before the eruption of a 3B /X3 flare is analytal numerically. It Ieads to the following condusions (l) the rotating motion nearby the footpoints of the filament system and shearing motion in the neighbourhood of the neutral line play an irnportant role in driving upward motion of the filament system. The ascending velocity of the filament can be up to 26 km /s before the flare beginning; (2) the dynamical behaviour of the filament system is influened by the background field medel. The deay of the magneti fiekl along with the hdght is exponenhal in AR4711.

FREQUENCY CHARACTERS OF FINE STRACTURE EVENT AT cm AND mm WAVELENGTH

XU Fuying, WU Hongao

1997, 17(1): 49-53. doi: 10.11728/cjss1997.01.049

Abstract(2199) PDF 333KB(856)

Abstract:
Based on the analysis for frequency characterestics of solar radio quasi-periodic pulsation at short cm and mm wavelengths, it is found that the reahve bandwidth of such a kind of event is 50%, and should be in wide bandwidth group. on the other hand, such a kind of phenomena occured bassically at the optical thin part or at about peak frequency of spectrum of related bulst. Thus, the fine structure may be cautal by gyro-synchrotron radiahon from quasi-periodic injechon of nonthermal electrons.

THE SOLAR CYCLE VARIATION OF CORONAL MASS EJECTIONS

KONG YongJin, WU Mingchan

1997, 17(1): 54-58. doi: 10.11728/cjss1997.01.054

Abstract(2393) PDF 304KB(887)

Abstract:
In this paper, Coronal Mass Ejection (CME) events observed with SMM (C /P) during l98O and l984 are reated with flares and eruphve filaments which occund in the saine periods. By Studying the distributions of velocity, there properties of CME is given,The results reveal that there are some changes in the frequency of occurrence of CMEx related with flares and filaments in the different period of solar cycle. From its maximum to the minimum years, the flares relatal frequency of occurrence of CMEs declined, and the filaments reated frequency of occurrence increased.Otherwise, energy of the activities associatad with CMEs is probably varied with ejective velocity . In generel, the faster the velocity is, the higher the energy of the activities is.

THE EFFECT OF THE EARTH MAGNETIC FIELD'S LONG-TERM CHANGES ON THE CALCULATION OF PROTON FLUX IN THE RADIATION BELTS

ZANG Zhenqun

1997, 17(1): 59-63. doi: 10.11728/cjss1997.01.059

Abstract(2277) PDF 344KB(1098)

Abstract:
In this paper, the changes of proton's fluxes for a certain posihon in the low altitude are caiculatal using IGRF magnetic field models with epoch from l945 to l990 and the latest trapped radiation model AP8MAX, and the effects of magnetic field's long-term changes on L, B /B₀ are discussed.The correct methods to calculate L, B /B₀ and the correct usage of trapped radiation belt models together with IGRF magnetic field models are recommended and discussed.

THE GEOMAGNETIC DISTURBANCE OF JUNE, 1991──THE CHARACTERISTICS ON THE GROUND AND AT THE GEOSYNCHRONOUS ALTITUDE

GAO Yufen, YANG Dongmei, ZHANG Gongliang

1997, 17(1): 64-69. doi: 10.11728/cjss1997.01.064

Abstract(2144) PDF 421KB(1107)

Abstract:
The charaderistics on the ground and at the geosynchronous altitude of the June l99l geomagnetic disturbance were described and the possible sources were analyzed . During this disturbance which lasted nearly 2O days, four geomagnetic storme with different intensity on main phases occurred as well as several strong sudden commencements. Some storms appeared to be the superposition of a few disturbanas and so were complex in shapes. At the geosynchronous altitude, reverse phase occurred many times on Hp component. All these phenomina might have mainly been the responces of the magnetosphere to the multiple high-velcity and high-intensity structures in the interplanetary space, Which at times assodatad with large-scaled strong southward IMF.

WIND AND WIND SHEAR OBSERVED BY ZN-1 ROCKET AT HAINAN STATION

MA Ruiping

1997, 17(1): 70-74. doi: 10.11728/cjss1997.01.070

Abstract(2275) PDF 302KB(1259)

Abstract:
Middle atmosphere sounding experiment was taken at HAINAN station in December, l988 using the ZN- l rocket. The principle of wind sounding by rocket as well as the results and the methods of data process is discussed in the paper. The results show that there ekist rather strong wind shears and gravity wave disturbance at the low latitude of the midddle atmosphere. There are distinctive differences between the rocket wind data and the CIRA 1986 or ISO reference atmosphere (ISO 5878-1982 /ADD. 1-1983).

SOME FEATURES OF PLANETARY WAVES IN THE MIDDLE ATMOSPHERE IN 1980

MU Xiangming, MA Ruiping

1997, 17(1): 75-84. doi: 10.11728/cjss1997.01.075

Abstract(2501) PDF 581KB(856)

Abstract:
Planetary waves and its propagation are very important in the middle atmosphere.Meteorologists have done a lot of researches on how the planetary waves vary in time-scales. Using the Nimbus 7 satelite grid data, this paper is concentratad on diagnosis and analysis of the Spatial structure of the planetary waves in the middle atmosphere in l98O. The results show that perturbations are mainly in the winter hemisphere and relatively weak in the summer hemisphere as well as equatorial areasl but can not be ignored. The transient waves which propagate to the summer hemisphere across equator is mainly through two height channels-2Okm and 70km. The standing waves stay in winter hemisphere. The attenuation of the amplitude from winter to summer can be found in wave l and wave 2. The energy in wave 3 neariy remains constant.

THE SPECTRA OF ATMOSPHERIC HORIZONTAL VELOCITY FLUCTUATIONS WITH HIGH-RESOLUTION IN THE ALTITUDE RANGE OF 80-100km

WU Yongfu

1997, 17(1): 85-89. doi: 10.11728/cjss1997.01.085

Abstract(2202) PDF 350KB(894)

Abstract:
High- resolution horizontal velocity data obtained from five chaff rockets performed during the "DYAN" campaign in the winter of l989 /l99O are used to discuss the consistency of the vertical wavenumber spectrum of the hodrintal velocity with the saturated spectrum of gravity waves and to determine the characteristic vertical scale in the altitude range of 8O-100km.

APPROACH TO SOME CHARACTERISTICS OF EARTH-TO-MOON TRAJECTORIES

CHEN Jianxiang

1997, 17(1): 90-96. doi: 10.11728/cjss1997.01.090

Abstract(2347) PDF 531KB(1069)

Abstract:
An approach to some characterishcs of moonward trajectories stated from circular parking orbit and lunar orbits by a patched conic technique is presented in this paper. If the earth-moon transfer traectory is coplanar with the Moon's orbit, the reahonships between selenocentric orbital paramcters and the injection conditions of transfer trajectories can be described by a set of algebraic equations; if not, by a set of simultaneous transcendental equahons which can be solved by an iterahve technique. Some conclusion are obtained by numrical simulations.