空间科学学报

1986 Vol. 6, No. 4

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The Ha Characteristics of Hard X-ray Bursts

Shi Zhong-xian, Wang Jing-xiu

1986, 6(4): 243-251. doi: 10.11728/cjss1986.04.243

Abstract(1931) PDF 605KB(608)

Abstract:
The following results are obtained from the examination of 50 Ha flares. (1) all flares with HXRBS are detectabe from the emission of Hα±2A. They have at least two Ha kernels (I flare/I bac. >1.15 on Hα + 2Å) located in the opposite polarity regions; (2) the Ha brigh-tenings start earlier than HXRBS, while the Ha peaks, which correspond to the spikes of HXRBS very well, come later than that of HXRBS by several seconds; (3) if the count rates of HXRBS are more than 1000, the kernels of Hα+2A cover the penumbra, if the count rates are less than 200, the kernels do not cover the penumbra.

The Analysis of Periodic Structure of Solar Wind Velocity

Zhang Xin-bo, Zhang Gong-liang, Qi Gui-zhong

1986, 6(4): 252-257. doi: 10.11728/cjss1986.04.252

Abstract(1862) PDF 506KB(1033)

Abstract:
Three kinds of spectrum analysis method are performed in order to study the regularities of distribution of solar wind. The first one is the general log power spectrum from which it can be seen that there is a overweighted 13-day period during the descending and minimum phases of the sunspot cycle, but in the ascending and maximum phases of the sunspot cycle, the spectrum is random. It seems that solar wind is in disorder during these periods. The second kind of spectrum analysis used is the maximum entropy spectrum which has better spectrum resolution. This gives out a different situation that the solar wind in the years of ascending and maximum phases of this sunspot cycle also possesses the 13-day period which far overweight the other periods. In order to verify further that there is really the same regularity of distribution of solar wind in ascending and maximum phases of the sunspot cycle as that in descending and minimum phases, a kind of filtering technique is performed, which is called cross-correlation filter. The third kind of spectrum is the power spectrum of filtered sequence. It is shown that solar wind in the years during which it would seem in disorder both in general power spectrum and in maximum entropy spectrum now possesses the overweighted 13-day period after being filtered. >

Oblique Propagating Ion Solitary Waves in a Magnetized Plasma

Song Li-ting

1986, 6(4): 258-265. doi: 10.11728/cjss1986.04.258

Abstract(1666) PDF 527KB(1042)

Abstract:
In recent years through in-situ electric field measurements in interplanetary space the local nonlinear ion electrostatic waves are often identified. They may be directely related to the acceleration of the auroral particles. These electrostatic waves are considered as either the ion acoustic mode evolution or the ion cyclotron mode evolution. In this paper the evolution of the ion nonlinear waves with small amplitude for oblique propagation in the magnetic fields are studied and the nonlinear Schrodinger equation is obtained. Calculation results show that it is possible for both the ion acoustic and the ion cyclotron solitary waves to exist. After making a comparison of the results with the electric field measurements on board of satellite S3₃ some observations can be well explained.

Ionospheric Refraction Correction in Radio Astronomy

Chai Yan, Han Wen-jun

1986, 6(4): 266-273. doi: 10.11728/cjss1986.04.266

Abstract(1767) PDF 633KB(919)

Abstract:
Using the Snell’s law in polar coordinates, the ionospheric refraction effects on the declination and right ascension determination is discussed in this paper. A ray tracing method is also given. With the ionospheric data observed in Beijing, the correction of ionospheric refraction is estimated and some usefull conclusions are drawn.

Convective Amplification of Irregularities in the Counter Equatorial Electrojet and Explanations of Some Observed Properties

Tu Chuan-yi

1986, 6(4): 274-280. doi: 10.11728/cjss1986.04.274

Abstract(1671) PDF 647KB(861)

Abstract:
The wave propagation and refraction of type "O" irregularities in the counter-electrojet conditions is investigated with a model electrojet in terms of the linear theory of the electrojet instability. Waves propagating with the electrons rotate their wave vectors downwards in the upper electrojet and upward in the lower electrojet. The ray-path integrated growth is much smaller than that in electrojet conditions for the same values of driven electric field |E_D| because the vertical component of group velocity is downward during the day and the electron density gradient is stabilizing. For the electron density characteristic length L_N = 6km and |E_D| = 0.8 mV/m, the integrated growth for wave length λ= 10m is less than 20 for altitudes h≥ 105 km. In these altitude range, waves may be not saturated. With increasing L_N, the value of |E_D| for waves still being linear at altitudes h ≥ 105 km decreases. The characteristics of the convective amplification mentioned above may be associated with some of the properties of the irregularities in the counter equatorial electrojet observed at Addis-Ababa in 1977 (reference
[6] ).

Analysis of Heating Condition of Coated Cb-752 Alloy Parts During Re-entry

Zhuang Yu-zhi, Zhuang Xiang-lin, Pu Gui-ling, Tang Quan-hong, Zheng Feng-zhen, Deng Yu-qing, Zhang Xi-zhang

1986, 6(4): 281-290. doi: 10.11728/cjss1986.04.281

Abstract(1811) PDF 2559KB(922)

Abstract:
In the present investigation, use is made of the structural characteristics at different temperatures of coated Cb-752 alloy to simulate the actual heating condition during re-entry. Specimens of coated Cb-752 sheets are successively heated from 1300℃ to 2200℃, the structure of these specimens is determined by optical microscopy, X-ray diffraction and electron micropro-be technique. The structure of the specimen taken from some specific parts of the actual recovered components is then compared with the coated simulated specimens and the temperature of that specific point on the actual components during re-entry assessed. In this way the criteria for analyzing the heating condition of coated structural parts are tentatively established. The method for analyzing the heated structural parts of coated Cb-752 alloy space vehicle during re-entry is also elucidated.

A Study on the Analysis Method of a Rotating Modulator

Xu Chun-Xian, Shen Chang-quan

1986, 6(4): 291-297. doi: 10.11728/cjss1986.04.291

Abstract(1609) PDF 588KB(920)

Abstract:
A rotating modulator designed for detecting point sources with energy range of near 150 keV is described. An analysis method for data of the rotating modulator is studied, which improves Durouchoux’s methods to suit a rotating modulator with a simple mosaic scintillator viewed by one photomultiplier instead of a positionsensitive detector array and uses a new response function derived. Then it is tested by Monte Carlo simulation.

Whistler Direction Finding from Great Wall Station at Antarctica

He Chang-ming

1986, 6(4): 298-302. doi: 10.11728/cjss1986.04.298

Abstract(1823) PDF 450KB(913)

Abstract:
During the first Chinese national antarctic research expedition, there is a high whistler activity at Great Wall Station on Jan. 20, 1985 and valuable whistler direction finding data are obtained by using our GM type VLF broadband receiver.The continuous observation from 17^h20^m to 18^h50^m shows that the exit points of whistler are situated in a strip of about 80 km wide in longitudes with an azimuthal direction 20°-40° E of N between 47.6° and 52.0° geomagnetic latitude. The ducts are all in the same strip region and there are no strong across L or longitudinal drifts. Therefore it is concluded that it is a process of the duct formation, growth, evalution into cluster and decay instead of the drifting of ducts into the "viewing window" of the station.

Characteristics of Ionospheric Scintillation of Geostationary Satellite Signals

Lei Yuan-han, Pi Xiao-qing, Ye Dong-ying

1986, 6(4): 303-309. doi: 10.11728/cjss1986.04.303

Abstract(1991) PDF 603KB(1011)

Abstract:
In this paper, a statistical analysis is made on ionospheric scintillations by processing the data of geostationary satellite beacon measurements and ionograms at Wuchang (114.4°E, 30.6° N) during May-Aug., 1983 and May-Dec., 1984. The results are (1) at Wuchang, ionospheric scintillations exhibit not only diurnal variations but also seasonal variations. In a year, May-July are months of maximum scintillation activity, but nighttime scintillation is closely associated with wavelike perturbation of Faraday rotation. To some extent, it can be said that ionospheric scintillations as observed at Wuchang belong to the type of middle latitude iono-speric scintillation; (2) it is found that there is a close relationship between indices of scintillation and fluctuations of the Faraday rotation, the correlation coefficient between their occurrences is larger than 0.8. Furthemore, it is estimated that both the correlation coefficient between occurrences nighttime scintillation and spread-F and that between occurrences of daytime scintillation and sporadic E are 0.60 and 0.55, respectively.

Discussion on the Calculation Method for Es Screening Intensity

Li Yu-hui

1986, 6(4): 310-314. doi: 10.11728/cjss1986.04.310

Abstract(2207) PDF 432KB(698)

Abstract:
In this paper the definition and calculation method for E_s screening intensity are discussed and improved. As simple calculation method is prE_sented for those path propagating by E_s.

A Preliminary Analysis of TEC Observed at Low Latitude Area

Jiang He-rong, Chen Pei-ren

1986, 6(4): 315-320. doi: 10.11728/cjss1986.04.315

Abstract(1627) PDF 548KB(599)

Abstract:
An observation of total electron content (TEC) was made in June and July, 1985 at a low latitude area. It is found that the northern crest of equatorial anomaly is somewhat around Guangzhou and Jiangmen with a osscilation to and fro around that position. The observed periods of gravity waves locally produced are less than 20--48 minutes and vary with latitudes. The large scale gravity waves generated in polar region can propagate to Guangzhou, but seldom to Hainan island. Irregularities appear mainly from 20-04 LT and sizes are not large. No dominant eastward drift is observed. Since the minimum of solar activity is approaching bubbles appeared only at Sanya in summer.

Study on Chemical Compositions of Boxian Chondrite, Anhui

Li Bin-xian, Gu Jing-fei, Zhang Xun

1986, 6(4): 321-324. doi: 10.11728/cjss1986.04.321

Abstract(1762) PDF 371KB(1087)

Abstract:
This paper deals with the chemical analyses of Boxian chondrite, Anhui. Using different methods, the concentrations of iron in metal phases and troilite. are determined. According to analytical results, all of the chemical parameters of chondrite are calculated, and mainly as follows: Fe/SiO₂= 0.50, SiO₂/MgO = 1.57, Fe⁰/Fe = 0.21. Together with the F_α value of 27-29% in olivene, the Boxian chondrite should belong to LL group.