空间科学学报

1986 Vol. 6, No. 3

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The Coronal Oscillations Revealed by Solar Hard X-ray Bursts

Xu Yong-xuan, Cao Yun-geng

1986, 6(3): 169-176. doi: 10.11728/cjss1986.03.169

Abstract(1667) PDF 522KB(914)

Abstract:
During the 21st solar activity cycle the HXEBS aboard SMM satellite and the HXM on HINOTORI spacecraft detected several thousand hard X-ray solar flares. Studies of the temporal properties of these events had revealed hundreds of examples of fast spikes with durations of less 1 sec. We analysed part of these observations and found that they have four common characteristics. Among these characteristics, quasi-periodic oscillations led us to believe the possibility of existing oscillations in the corona. We have studied the characteristics of the oscillations and derived their periods. The conditions of trapping the oscillations are also discussed.

The Influences of Solar Flares on Ionospheric Electron Content

Ye Zong-hai, Jiang He-rong

1986, 6(3): 177-183. doi: 10.11728/cjss1986.03.177

Abstract(1759) PDF 498KB(1241)

Abstract:
This paper provides a statistical study of the disturbance of ionospheric electron content initiated by solar flares over importance one for 1978-1979. It shows the different effects of solar flares grouped by their importance, duration, season and the distance from the solar central meridian. The results show that ionospheric electron content is obviously disturbed by the bright solar flares with duration longer than 1.5 hours. The electron content starts to increase after the occurrence of solar flares and reached its maximum on the fourth-fifth day. The electron content disturbances caused by non-bright flares is smaller than by bright filares. Solar flares with duration <1.5 hours do not disturb the electron content. The flares occurred in the summer seems not to disturb the electron content. Only the flares occurred in the winter obviously disturb the electron content. There is an east-west asymmetry in distribution of flare’s position in causing the electron conten distinct disturbances. Flares occurred on the east 61-90E from the solar central meridian and in winter seasons induce the largest disturbances for the electron content.

A Preliminary Investigation on the Correlation between Ion Velocity and Geomagnetic Pulsation

Zhao Zheng-yu

1986, 6(3): 184-191. doi: 10.11728/cjss1986.03.184

Abstract(1770) PDF 575KB(968)

Abstract:
Using rich ionospheric data collected from the six days operation of the BISCAT in 1983, an analysis is made on ion velocity and geomagnetic pulsations. It is found that there is a good correlation between ion velocity and P_c 3-5 pulsations.

The Explanation of Umbral Dot of Sunspot

Tong Yi, Du Jin-sheng

1986, 6(3): 192-195. doi: 10.11728/cjss1986.03.192

Abstract(1948) PDF 289KB(905)

Abstract:
In this paper, the form of umbral dots of sunspot was satisfactorily explained by a mechanism of local perturbations in a magnetic tube of sunspot along with the theory of Petschek’s neutral sheet. On the other hand, the special properties of umbral dots of sunspot such as the temperature, magnetic field and its life-time were estimated by Petschek’s formulae. The obtained results were agreed fairly well with observations.

Comparison of the Correlations between the Interplanetary Parameters and Geomagnetic Indexes

Wu Hong-zhong, Du Heng

1986, 6(3): 196-202. doi: 10.11728/cjss1986.03.196

Abstract(1720) PDF 493KB(1223)

Abstract:
Regression and multiple regression are performed for the data of mean houly values, mean daily values, and daily ranges of interplanetary parameters and geomagnetic indexes in the period of 1966-1975. The correlations between interplanetary parameters and geomagnetic indexes are analysed and compared.

The Enhancement of Ionospheric Es in the Far East and Its Related Factors

Tan Zi-xun, Cheng Xiao-ping

1986, 6(3): 203-210. doi: 10.11728/cjss1986.03.203

Abstract(1612) PDF 500KB(965)

Abstract:
The relationship between the enhancement events of ionospheric Es in the Far Bast region of the world and geomagnetic activity is examined. The approach adopted in this paper is to use local geomagnetic index K in the superposed epoch analysis and special emphasis is put on the night time Es echoes with large amplitudes of variations, so that some remarkable results may be expected. Among 1213 enhanced Es events analysed in this paper, about 70% is accompanied by the conditions of L>4 or K>2 within 11 hours before the event. The remaining enhanced Es, either occurred on geomagnetic quiet days and seems to be associated with some gradual commencement storms occurring in neigboring Hyderabad, India, or occurred before certain large geomagnetic storms.

The Crossing of Cold Front and the Night f₀F₂

Shen Chang-shou, Zi Min-yun

1986, 6(3): 211-216. doi: 10.11728/cjss1986.03.211

Abstract(1967) PDF 413KB(926)

Abstract:
The effects of the cold fronts upon the night f₀F₂ are found out by using the records from the cold fronts years book and ionosonds measurements of Wulumuqi and Changchun. From the statistical analyses of large number samples from 1968 to 1975 and the superposed epoch analyses with the day of the minimum temperature during the processes as the key day, it is shown that the f₀F₂ tends to decrease when a could front passes across. The maximum decrease is at the key day in the superposed epoch analyses. The pereentage values of the decreases are 4%-8%. It is larger in solar low-activity years, and the variation is also larger in Wulumuqi than in Changchun, x²-and U-test have been used to demonstrate the significance of the respose. The effects are probably caused by the gravity waves from the Jet-stream?generated Kelvin-Helm-holtz Instability within the cold front area. Gravity waves may propagate upward and produce the up-down oscillation in ionosphere. The integrated decrease of the f₀F₂ and the difference between the high and low activity years can be interpreted by his mechanism as well as the station-to-station difference.

A Method of Profile Simulation Reduction for Ionogram

Huang Xin-yu, Tan Zi-xun, Su Yuan-zhi

1986, 6(3): 217-222. doi: 10.11728/cjss1986.03.217

Abstract(1837) PDF 327KB(865)

Abstract:
A method of profile simulation reduction for ionogram using one single-component trace is proposed. It can be used to determine the profiles of the ionosphere with multi-layer structures. The program of the mothod is simple and measured values required for reduction is less. It is convenient for routine profile analysis of the network of ionosphere stations.

Computation of the Topside and Bottom-side Ionospheric Data in Hai Kou Region

Liu Pei-jing

1986, 6(3): 223-226. doi: 10.11728/cjss1986.03.223

Abstract(1537) PDF 262KB(857)

Abstract:
In this paper, the differential Doppler measurements and the f₀F₂ measurements taken in Had Kou region during the period June-December 1981 are analysed to obtain some characteristics of the topside and bottom-side ionosphere at the low latitude. These results provide us a reliable basis for the study of the high-altitude ionosphere at low latitude.

Experiments and Calculations of the 100 kHz Sky-wave

Wang Xian-lin, Shen Li, Huang Ze-rong

1986, 6(3): 227-232. doi: 10.11728/cjss1986.03.227

Abstract(1786) PDF 408KB(1454)

Abstract:
In this paper, the annual, monthly and day-to-day variations the 100 kHz Loran-C pulse signal are given for both before and afternoon times by analyses of some experimental results and calculations, An approximate formulae for estimating the observational phase, phase height of reflection and the triangulation height is also given.

Isotopic Lead Investigations on Bo County Chondrite of Anhui Province, China

Peng Zi-cheng

1986, 6(3): 233-239. doi: 10.11728/cjss1986.03.233

Abstract(1819) PDF 487KB(973)

Abstract:
The isotopic compositions of lead were determined on the samples of whole rock, chondrule, olivine, pyroxene and troilite from Bo County chondrite (class LL4) of Anhui prov., China. Uraium, Thorium, and Lead concentrations of those samples were partially analysed. Observed ²⁰⁶Pb/²⁰⁴Pb ratios varied from 9.87 to 20.38; ²⁰⁷Pb/²⁰⁴Pb ratios from 10.51 to 16.61; ²⁰⁸Pb/204 Pb ratios from 30.20 to 40.58. In ²⁰⁷Pb/²⁰⁴Pb-206 Pb/²⁰⁴Pb diagram, a regression line fitted to most of data from Bo County and Bru-derheim-III and Modoc meteorites, has a slope of 0.6095 + 0.0095, corresponding to the model age of 4.53 ± 0.02 AB and the line is through the primordial lead of Canyon Diablo troilite. However, the age, corresponding to the internal isbehron line of Bo County chondrite, is 44.4±0.02 AE. It is reasonable to think that Bo County chondrite was formed at 4.53±0.02 AE ago and suffered in the early melting event at about 0.1 AE ago after formed. In a coreordia diagram the data plot a chord intersecting concordia at 4.54±0.02 AE and 0.4 AE. This indicates disturbance of the U-Pb systems happened relatively recently. The Th/U ratio from the ²⁰⁸Pb/²⁰⁴Pb- ²⁰⁶Pb/204 Pb diagram of the Bo County samples is 4.0 + 0.1, which is slightly higher than the normal value of 3.8. It is possible that Bo County chondrite might have suffered a thermal event.

A New Method of Observing and Investigating the Comet Dust from the Ground

Xie Guang-zhong, Liu Xin-de, Li Kai-hua, Zhang Yun

1986, 6(3): 240-242. doi: 10.11728/cjss1986.03.240

Abstract(1732) PDF 269KB(858)

Abstract:
According to different models of the absorption coefficient of the comet dust, the equations of radiation balance are solved respectively. The temperatures of the dust with different properties, dimensions of grain and heliocentric distances have been obtained. If we take the colour temperature determined by the real temperature of the dust, then we can study the properties of the dust only by means of the near-infrared ground-based observations without need for far-infrared spatial observations.