空间科学学报

1993 Vol. 13, No. 2

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A NUMERICAL SIMULATION FOR THE PROPAGATION OF DISTURBANCE IN THE SOLAR CORONA (III) THE EFFECTS OF SOLAR WIND

Wang Shui, Zhang Bing, Zheng Hui-nan

1993, 13(2): 81-89. doi: 10.11728/cjss1993.02.081

Abstract(2024) PDF 593KB(637)

Abstract:
In this paper, the dynamical response under the basic state with two-dimensional magne-tohydrodynamic equilibrium in the solar corona caused by the radial ejection of cold mass at the solar surface of the open magnetic field is studied numerically. The results show that: (1) a weak disturbance propagates upwards with the Alfven velocity on the front of loop with high plasma density; (2) the moving velocity of the leading edge of loop increases as the radial distance increases, and the increment is nearly equal to the local velocity of solar wind; (3) the maximum of plasma radial velocity in the loop approaches to the local escape velocity at four solar radii; (4) the feet of loophave not any obvious expansion for the open region with stroni magnetic field. These results may explain the solar prominence and the accompanying coronal mass ejection.

MHD SIMULATION OF INTERACTIONS BETWEEN TWO NEIGHBORING INTERPLANETARY SHOCK WAVES-ANGULAR EFFECTS

Lu Jian-yong, Wei Feng-si, Gu Hui-cheng

1993, 13(2): 90-97. doi: 10.11728/cjss1993.02.090

Abstract(2627) PDF 535KB(915)

Abstract:
The MHD 2(1/2)D, time-dependent model is used to investigate neighboringinterplanetary shock wave interactions in the equatorial plane, with different angular separations. For tow shocks with initial velocity v_s= 1000 km/s, the main results are: For the case of angular separation Δφ=24°, the two shock waves completely coalesced into a new shock within 1 AU; For the case of Δφ = 36°, the two shock waves coalesced into a new shock wave near 1AU; For the case of Δφ= 48°, the azimuthal collision of the two shocks occured, and a coalescence could partly be seen within 1 AU;For the case of Δφ = 72°, one would not almost see the collision of the two shock waves, that is their propagations are independent each other.For the two shocks with initial velocity v_s= 2000 km/s, main results are: For the case of Δφ ≤48°, the two shock waves completely coalesced into a new shock within 1 AU; For the case of 54°, the two shock waves coalesced into a new shock near 1 AU; For the case of Δφ = 72°, the two shock waves collided azimuthally, but could be identified from their distributions; For the case of Δφ = 120°, the two shock waves propagated independently.

THEORETICAL STUDY ON THE NONLINEAR WAVES IN A LOW-β CYLINDRICAL SYMMETRY MAGNETIC TUBE

Shi Jian-kui

1993, 13(2): 98-106. doi: 10.11728/cjss1993.02.098

Abstract(2093) PDF 503KB(885)

Abstract:
The nonlinear plasma density waves in a low-β cylindrical symmetry magnetic tube are discussed. The results show that: (1) if |(a/M²-1)E₀| < 1 or a/M²> l, |(a/M²-1)E₀| > 1 and G_m > 1 + |(a/M²-1)E₀|, there exist periodic waves; (where a = Ti/Te+ 1, Ti and 7% are the ion and electron thermal energies respectively, Mis the ratio of phase velocity of wave and ion acoustic velocity, E₀ isinitial electrical field, (G_m=√a/M²exp(1-a/M²)/(2a/M²)). (2) if |(a/M²-1)E₀| = 1 and G_m≤2, there exist shock waves; (3) if a/M² > 1, | (a/M²-1)E₀| = 1 and G_m>2, there exist hollow solitons; (4) if a/M²< 1, |(a/M²-1)E₀|≥1 and G_m> 1 + |(a/M²-1)E₀| or |(a/M²-1)E₀| > 1 and G_m≤ 1+|(a/M²-l)E₀|, there exist raised solitons. The amplitude of waves is discussed also.

THE MODIFIED B-KdV EQUATION OF SHEARED MAGNETO-HYDRODYNAMICS IN THE COMET-TAIL AND ITS NONLINEAR PROPERTIES

Gan Shi-pan, Hong Ming-hua, Wang Xian-min

1993, 13(2): 107-115. doi: 10.11728/cjss1993.02.107

Abstract(1936) PDF 524KB(925)

Abstract:
Using the two-dimension reductive perturbgation method in this paper, the modified B-KdVequation of sheared magnetohydrodynamics in the comet-tail is derived and its nonlinear properties are investigated qualitatively. The primary results are: (1) Amodified B-KdVequation of sheared modified magnetohydrodynamice in comet-tail is derived; (2) The restrictive relations about macroscopic nonlinear wave acd sheared background in comet-tail are given; (3) The complicated structures in plasma comet-tail are explained qualitatively, and (4) Atransfer mechanism of interaction between solar wind and plasma in comet-tail is given.

THERMOLUMINESCENCE ANALYSIS METHOD OF SPACE RADIATION DOSE INFORMATION ABOARD THE CHINESE SCIENTIFIC EXPERIMENT SATELLITES(1987-1990)

Zhang Zhong-lun, Zheng Yan-zhen, Su Zhen, Zhao Ke-jian, Liu Cheng-xiang

1993, 13(2): 116-121. doi: 10.11728/cjss1993.02.116

Abstract(2293) PDF 421KB(940)

Abstract:
The thermoluminescence analysis method of space radiation dose information aboard the experiment satellites are described in this paper. Using LiF (Mg, Cu, P) detectors and pro-grammed-heating, the space radiation daily dose in experiment satellites were measured. It is lower than 20mrad/day, the background luminescence of detectors and way that reduce influence of low-temperature peak and inhomogeneity of irregularities of dos distribution formed by high-LETparticles are studied by LiF (Mg, Ti) and CaSO₄ (Tm) detectors and glow curve deconvolution.

THE CHARACTERISTICS OF SOLAR X-RAY EMISSION FOR PROTON FLARES AND PROTON EVENT WARNING

Lin Hua-an Wang Shi-jin

1993, 13(2): 122-128. doi: 10.11728/cjss1993.02.122

Abstract(2269) PDF 493KB(907)

Abstract:
Studying the characteristics of solar X-ray emission for proton flare will provide an important way and method for proton event warning. The observational data of proton flares and relevant X-ray emission obtained by GOES and SMMsatellites during the 21st Solar Maximum are analysed in this paper. It shows that, for most proton flares, the hard X-ray emission has following properties: the peak flux F_HX≥10^{4^{c/s, duration time T_n≥10³sec, maximum X-ray photon energy E_x≥300 keV, average spectral index<3.5, high energy time delay T_L> 10 sec, integral flux F₀>10⁶counts, rising time T_R>10²sec. By using these characteristic parameters to warn the proton events, the a correct prediction rate of 94% and a false prediction rate of 40% are obtained respectively.}}

STUDY OF MICROWAVE BURSTS ASSOCIATED WITH SPOTLESS FLARES

Ji Shu-chen, Zhao Ri-sheng, Ma Yuan, Cao Wen-da

1993, 13(2): 129-133. doi: 10.11728/cjss1993.02.129

Abstract(2268) PDF 341KB(615)

Abstract:
During 1980-1984, It is found that the spotless flares are associated with eleven groups of microwave burst in solar radio data observed with the radiotelescopes at 9375 MHz, 3653 MHz and 2902 MHz. In this paper, the temporal behavior and peak-flux-density of the microwave bursts are studied. They are long duration, small flux and gradual rise-and-fall events. Source size of microwave bursts is similar to spotless flare source, they may occur in low coronal layer or in chromospheric high layer. Finally, their emission mechanism are confirmed as thermal bremsstrahlung from electrons with Maxwellian distribution.

THE EFFECTS OF SOLAR FLARES ON VLF RADIOWAVE PROPAGATION

Liu Wan-tong

1993, 13(2): 134-139. doi: 10.11728/cjss1993.02.134

Abstract(2040) PDF 389KB(612)

Abstract:
The loss of phase period of VLFradiowaye propagation during solar flares is discussed based on experimental data. Furthermore, the mechanism of loss of phase period is explained utilizing a theory of antipodal propagation. Loss of phase period is an improtant phenomenon of radiowave propagation, especially, the propagation of LFand VLFradiowaves. The phenomenon discussed above is seldomly seen in past references. Therefore, discussion on the problem is of special significant.

CHECKING TWO-DIMENSIONAL SYMMETRIC MODEL OF RING CURRENT BY THE EFFECTS OF EQUATORIAL RING CURRENTS ON COSMIC RAY

Sun Xiao-qing Ye Zong-hai

1993, 13(2): 140-145. doi: 10.11728/cjss1993.02.140

Abstract(2216) PDF 361KB(653)

Abstract:
Using the data from 11 ground-based super neutron monitors, this paper deals with the effects of equatorial ring currents on cosmic rays, which include that of storm-time increases and cut off rigidities in the analysis of this paper, during periods of six geomagnetic storms of 1984-1989. It is shown that the storm-time increases are due to the existence of westward equatorial ring currents developing or intensifying during geomagnetic storms. The storm-time increases are of latitude and local time dependence and the intensifying ring currents can cause the depression of cosmic ray cutoff rigidities. By comparing the storm-time increases and the registrations of H-component recorded by Beijing Standard Seismic Station. It can be seen that they correlate negatively with each other. On the basis of two-dimensional symmetric model of ring current, it is also shown that, except some very large storms, the expected decreases of H-component originated from a ring current which are calculated with this model are in good agreement with the actual observations on the ground.

CHARACTERS OF PLANETARY SCALE OSCILLATIONS IN THE EIA AND ITS YEARLY VARIATION AND RESPONSE TO THE QBO

Luo Yi Chen Pei-ren

1993, 13(2): 146-152. doi: 10.11728/cjss1993.02.146

Abstract(2360) PDF 512KB(983)

Abstract:
Long period oscillations of plasma in the equatorial ionization anomaly (EIA) are analyzed with the data from the EIAcrest-region station (Okinawa) during 1977-1990. The oscillations have periods at 2-2.5, 3-4, 5-7 and 10-18 days, and make an appearance in all seasons. Its relative amplitude, however, are large in summer and even larger in winter months. There is also slight variation on seasonal distribution for different periods. The 2 day wave is stronger in summer and the near 2.5 day wave in winter. The summer amplitude peak of the longer period oscillations tends to split and shift to the beginning and end of the summer month. All these characters are consistent with the observational results of the neutral wind oscillations in the mesosphere. In the year-by-year variations, it is revealed that the EIAlong-period oscillations are negatively correlated with the solar activity, and the longer the period the more obvious the negative correlation. We also show that the occurrence of the 2-2.5 day wave and period at 10-16 day wave are modulated by the equatorial QBO. In east phase of QBO, it is easier to see the EIAlong period oscillations.

A STATISTICAL MODEL FOR TOTAL ELECTRON CONTENT

Jian He-rong, Yang Mei-hua, Liu Yu-ling, Wu Shun-zhi

1993, 13(2): 153-158. doi: 10.11728/cjss1993.02.153

Abstract(2407) PDF 377KB(1074)

Abstract:
After analysing the data of TECand f₀F₂, measured at Beijing, a statistical relationship between Total Electron Content, sunspot numbber Rand ionospheric critical frequence f₀F₂ is obtained.

A MODIFIED TAIL-SUSPENSION MODEL FOR SIMULATING LONG-TERM WEIGHTLESSNESS

Chen Jie, Ma Jin, Ding Zhao-ping, Zhang Li-fang

1993, 13(2): 159-162. doi: 10.11728/cjss1993.02.159

Abstract(3425) PDF 329KB(2230)

Abstract:
The rat tail-suspension model may be more acceptable for simulating weightlessness than other animal models in the view of its less stressful situation. However, there are problems of injury to the skin and development of abscesses and ischemic necrosis of the tail. Inorder to minimize this traumatic nature of the technique and make longer the suspension period, modifications are made to the Morey-Holton and Wronski's tail-suspension method. The main points are as following: (1) Apart from tincture of Benzoin, tincture of resin is spracyed on the tails, which help to unsmooth the tail surface and firm the attachment of the adhesive tape stripes. (2) The taping places on the tail are changed regularly every 7 days. For this reason, the tail surface is divided into four sides and only two opposite ones (upper and below or left and right) are applied with tape stripes, leaving the other two unattached for the later taping place replacement. (3) The traction force acting on the tail is mainly carried by the tape stripes attached longitudinally with the tail rather than those twining around the tail. These modifications effectively protected the tail from ischemic injures caused by the surrounding tape stripes either by the force acting on the tail or the constriction of the tail as the rat grows. The skin injuries by the irritation or tearing of the tape strips rarely happened and could recovery soon after the taping place replacement. The modified tail-suspension is well tolerated by five groups of male SDstrain rats (10 animals per group)for 90 to 120 days, as evidenced by normal feeding, normal grooming behavier and a continued weight gain kept close to or almost same as that of pair-fed control groups hroughout the suspension period. So it may be a useful model for simulating the effects of long-term weightlessness.