1983 Vol. 3, No. 2

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METHODS OF LARGE-SCALE SYSTEMS AND SATELLITE ATTITUDE DYNAMICS
Wang Zhao-lin, Liu Shou-gui, Guan Ye-hui, Huang Shi-tao
1983, 3(2): 81-102. doi: 10.11728/cjss1983.02.081
Abstract(1454) PDF 1609KB(1152)
Abstract:
This paper presents a method that can be applied to analysis of the stability of nonlinear unsteady mechanical systems,based on Chetaev's theory and the theory of the largescale systems: methods of large-scale systems with weighted Vfunction.Moreover,this method is used for the research on the problems of attitude stability of dual-spinning satellite,the large flexible spacecraft and the satellite with cavity containing fluid.It can be seen that this method can be applied effectively to analyzing the stability of the mechanical systems with constraint damping,the gyrosystems and the complex systems of spacecraft.
RESEARCH ON METHODS FOR DETERMINING THE MAGNETIC MOMENT OF A SATELLITE IN EARTH'S MAGNETIC FIELD
Jia Wen-kui
1983, 3(2): 103-112. doi: 10.11728/cjss1983.02.103
Abstract(1610) PDF 899KB(1072)
Abstract:
Magnetic design and test should be considered in the design and making of a satellite,because the magnetic torques resulting from the interaction between the magnetic properties of the satellite and the ambient magnetic field tend to disturb its attitude.This paper presents the ambient field mapping method to determine a satellite magnetic moment.Its main point is to acquire experimentally and deduce mathematically the magnetic field data of a satellite in the limited region in earth's field.In order to do that,we must overcome two main difficulties: separating permanent moment from induced moment;effectively inhibiting noise of earth's field.This method has resolved these problems by using the following techniques in a better way:1,repeating measurement at original and inclined (or inverse) position.2,obtaining the difference between the outputs from the measuring probe and the reference probe.3,let the axis of the probe direct to the earth's field east,turning the test subject over 90° of angle to keep relative magnetic state between it and the probe.The results that have been attained by analysis and test indicate that the error is not more than 10% for magnetic moment above 500 mA-m2.It can be expected that the precision can be increased after improvement.
MAGNETOHYDRODYNAMIC BEHAVIOUR OF DISTURBANCE OF FINITE AMPLITUDE MAGNETIC FIELD IN THE SOLAR ATMOSPHERE
Liu Xin-ping
1983, 3(2): 113-121. doi: 10.11728/cjss1983.02.113
Abstract(1331) PDF 691KB(962)
Abstract:
In this paper,dynamic processes in the solar atmosphere are studied numerically from a complete set of MHD equations.Dynamic evolution of nonlinear magnetic field is produced by the finite amplitude of the azimuthal magnetic field at the base of the flux tube of the solar atmosphere.It is assumed that the initial configuration of the magnetic field is a force-free and potential field,the magnetic field is disturbed at the base,the plasma is driven and a part of magnetic energy is transformed into the kinetic energy of the plasma.The compressed flow of the plasma has the features of fast MHD waves.The computation results give quantitatively the nonlinear evolution of strong magnetic fields.These results could apply to the explanation of coronal transients,surge,spray and eruptive prominence events in the solar atmosphere,and to the modelling of plasma behaviour in high-βstructure experiments in the laboratory as well.
THEORETICAL TREATMENT OF THE MAGNETOPAUSE CUSP
Fu Zu-feng
1983, 3(2): 122-134. doi: 10.11728/cjss1983.02.122
Abstract(1426) PDF 931KB(951)
Abstract:
Chapman-Ferraro model is solved for a three dimentional magnetopause.It is proved theoretically that there is a demarcation line with definite length of about 40° through the cusp region.The surface of the magnetopause is angled along this line,on which every point is an exit for the earth's field line to emerge from the magne-tosphere.The neutral point is just the intersection of the demarcation line by the meridian plane.
THE BLAST WAVE PROPAGATING IN A VARIABLE DENSITY MEDIUM WITH RING-MAGNETIC FIELD
Wei Feng-si
1983, 3(2): 135-145. doi: 10.11728/cjss1983.02.135
Abstract(1374) PDF 839KB(1071)
Abstract:
The non-similar questions of the blast waves which propagate in a variable density medium with ring-magnetic field has been treated.On the basis of the analytical solution obtained by this paper the propagating of the solar flare-shock waves have been discussed.When the flare shock waves propagate into the interplanetary space,the configuration of magnetic field appears U-type,and mainly occurs in the part of the head of a shock wave (>0.5R).It has some similarity as the cosmic ray storms and the magnetic storms.Particularly noteworthy is the fact that the flare-shock waves must have higher energy than the magnetic cut-off energy Em=(λ1S2/4π) j0Rsh1,j0 are the parameters relative to a shock wave respectively,8 is the constant proportional to the ring-magnetic field at the reference point).It is possible that the flare-shock waves propagate into the interplanetary space.The ring-closed region of the magnetic field has stronger constraint to the propagation of the shock wave.It can be qualitatively explained that after the occurrence of the solar flare-shock waves a number of geophysical disturbance phenomena are not always observable on the earth,which will be relative to the configurations of the magnetic field on the solar flare.
X-RAY STUDIES OF QUASARS
Zhang He-qi, Liu Bu-liang, Yang Hai-shou
1983, 3(2): 146-156. doi: 10.11728/cjss1983.02.146
Abstract(1517) PDF 960KB(999)
Abstract:
In this paper,a statistical study is made of the evolution of X-ray radiation of 273 objects (235 quasars and 38 type I Seyferts) in the 0.5-4.5 keVband observed from the Einstein Observatory.On the Lx-z plot of these 273 objects,there seems to exist a natural physical sequence (the QE band),which connects the active galaxies such as quasars and Seyferts in the sense of energy and the mass distribution of the central compact objects (hence the distribution of accretion rates).On the basis of the spherically symmetric accretion model of a massive black hole,the preliminary analysis of this sequence shows that quasars may quickly cross the lower envelope of the QE band and leave it and then disappear.Due to large accretion rates,the time of staying on this QE band for high-redshift quasars is found to be comparatively short (~106yr),while that for low-redshift quasars and type I Seyferts is longer (~108yr).These results agree with observations.Therefore,active galactic nuclei such as quasars and Seyferts may be manifestations of galactic nuclei in an excited state under specific conditions.Using the available monochromatic radio,optical and X-ray luminosities lr lo and lx of 107 quasars,we find that there exist two evolutionary stages in the optical luminosities of quasars: the optically bright and optically faint stages.In each of these stages,the parameters characterizing the typical properties of quasars are evidently distinctive.The change of spectrum types may imply that the radiation mechanisms in different energy regions are different.
THE PROPAGATION OF COSMIC RAYS IN INTERSTELLAR MATTER:PATHLENGTH,RESIDENCE TIME AND AGE
Huang Yong-nian, Cheng Tung-yuan, Zhang Gong-liang
1983, 3(2): 157-161. doi: 10.11728/cjss1983.02.157
Abstract(1490) PDF 409KB(893)
Abstract:
The escape path length,the residence time and lifetime of cosmic rays in the Galaxy are determined by analyzing the HEAO-3 C-2 data on the relative abundance of manganese to iron in terms of the solutions of cosmic ray propagation equations derived in paper [1].
ON THE ANALYSIS OF GEOMAGNETIC EFFECTS OF THE SOLAR ECLIPSES DURING THE GEOMAGNETIC DISTURBANCES
Zhang Jing-xiu, Liu Chang-fa, Du Tie-liang, Wang Mei-ying, Wei Yong-jia
1983, 3(2): 162-169. doi: 10.11728/cjss1983.02.162
Abstract(1393) PDF 723KB(898)
Abstract:
This paper analyzes the geomagnetic effects of the annular solar eclipse of April 19,1958 and the total solar eclipse of September 22,1968.The method used is based on the difference of the disturbance field in different areas.The magnitude and direction of these effects with reference to the eclipses are qualitatively discussed.
CHARACTERISTICS OF WHISTLER PROPAGATION AT WUCHANG AND THEIR CORRELATION WITH GEOMAGNETIC ACTIVITY
Chen Song-bo, Xu Ji-sheng
1983, 3(2): 170-176. doi: 10.11728/cjss1983.02.170
Abstract:
In this paper,the general characteristics of low-latitude whistler propagation is investigated by analysing the data obtained at Wuchang (geom.lat.19.2°N) for last three years.Attention is paid to the study of whistler propagation paths.Besides,a closed examination is made of the correlation between the whistler parameters at Wuchang and ionospheric electron concentration,as well as the geomagnetic activity.A good correlation has been found between whistler dispersion and f0F2.It is also shown that there exists a type of whistler with stationary dispersion values,the occurrence rate of which is much higher than other types.This is one of the remarkable features of whistlers at Wuchang,showing that in the low-latitude ionosphere region there possibly exist stationary and recurrent whistler propagation paths.In addition,analysis of typical events and statistical calculation both show that the occurrence rate of whistlers increases considerably during magnetic storms.The dispersion value slightly increases following the SSC of the storms,the amplitude of the increase being 118-137% of the monthly mean value.