1987 Vol. 7, No. 2

Display Method:
Height Profile Inversion of the Ionospheric Movement from the Observed Parameters of HF Radio Echoes
Wan Wei-xing, Li Jun
1987, 7(2): 85-94. doi: 10.11728/cjss1987.02.085
Abstract(1556) PDF 627KB(1660)
Abstract:
Under the condition of an unstable, inhomogeneous and anisotropic ionosphere, some relations among the dynamic parameters of the ionosphere and the observables of HFradio echoes reflected from the ionosphere are derived from the general ray equations. On the basis of these relations, a method is proposed to invert the height profile of the electron density, N(Z), and the height profile of the normal velocity, V(Z) of the constant electron density surface from the observed Dopplionogram, gonionogram, ionogram and rangionogram. Furthermore, comparing the possible combination of the radio wave obserables which are necessary and sufficient for the determination of the height profiles of V(Z) and N(Z), the authors suggest a new operation mode of ionosonde to observe the large scale ionospheric disturbances such as the gravity waves from a single station. This may be the theoretical basis for data analysis and instrumental improvement of modern ionosonde.
The Time Delay of the Ionospheric Response to the Ring Current Variation
Shen Chang-shou
1987, 7(2): 95-102. doi: 10.11728/cjss1987.02.095
Abstract(1430) PDF 570KB(959)
Abstract:
The link between intensification of the ring current inflation rate and the variation of ionospheric electric fields during the long-lasted storms is discussed. The main features of the ionospheric response to the ring current variation observed by STAREand SABREare the following: (1) The ionospheric response has a time delay of 1-2 hours in the afternoon sector of MLTwhere the electric field increases as a near-exponentiasl function, while in other sectors there is no delay and no systematic increase of electric fields, but an enhanced state with fluctuations, can be found. (2) Opposite tendency of electric field variations often appears from STARE (70.2°N) and SABRE (65.8°N) observations. (3) In the STAREfield of view the magnitude of electric fields at lower latitude (70.2°N) is usually larger than that at higher latitude (71.8°N) during ring current increase events. These facts are consistent qualitatively with predictions of simple model of Zi and Shen, 1986. The results show that the ring current has an important influence on the magnetosphere-ionosphere coupling.
Electrostatic Ion Cyclotron and Ion Acoustic Wave Instavilities Driven by Upgoing Oxygen Ion (O+) Beams on Auroral Field Lines
Zhou Guo-cheng, Wang De-ju
1987, 7(2): 103-116. doi: 10.11728/cjss1987.02.103
Abstract(1540) PDF 857KB(671)
Abstract:
An investigation is made on the instabilities of electrostatic oxygen ion (O+) cyclotron and ion acoustic waves in a model plasma consisting of background hot electrons, background cold protons (H+), and strongly anisotropic oxygen ion beams. It is shown that the lower frequency and electrostatic O+ ion cyclotron and ion acoustic waves may be excited by upgoing O+ ion beams on auroral field lines. Upgoing O+ ion beams may be an important source of free energy for the lower frequency and electrostatic instabilities on auroral field lines.
Estimation of Sqe Current System Focus by Means of Geomagnetic Data at Middle and Low Latitudes
Xu Wen-yao
1987, 7(2): 117-127. doi: 10.11728/cjss1987.02.117
Abstract(1353) PDF 635KB(1366)
Abstract:
The relationship of geomagnetic field at the earth's surface with Sqe current systems is analysed. It is pointed out that there exsist some differences between the true focus of the Sqe current system and the "apparent focus" determined by using Sqe variations in the geomagnetic field at the earth's surface. Practical approaches to estimating Sqe current focus by means of geomagnetic data are discussed and examined by using geomagnetic data during the period of IGY/C.
Auroral Kilometric Radiation and Auroral Hiss:DE-1 Observation Results
Wang Yuan-dian, Liu Qing-ling
1987, 7(2): 128-133. doi: 10.11728/cjss1987.02.128
Abstract:
Data of plasma waves observed by DE-1 are analyzed for some time periods. In this paper, some results, mainly about AKRand auroral hiss, are given. The frequency range of AKRis from 50 kHz to 400 kHz or more, but the peak intensity is around 200 kHz. The maximum electric field spectral density can reach 10-11V2m-2Hz-1 or more. The frequency range and intensity vary with the observation positions. Usually there are several intensity peaks in the frequency range. The relative amplitude of the peaks and the frequencies correspondent to the peaks vary with the position of the satellite rapidly. As to auroral hiss, there are upper and lower frequency cut-offs. The upper frequency is either the electron gyrofrequency or the electron plasma frequency, depending on which one is the smaller; the lower frequency cut off is due to the propagation effect.
Anomalies of the Ionospheric F2-layer above Guangzhou Region
Huang Qing-ming
1987, 7(2): 134-138. doi: 10.11728/cjss1987.02.134
Abstract(1576) PDF 337KB(886)
Abstract:
Guangzhou Ionospheric Observatory is located near the geomagnetic equator (geomagnetic coordinate 183.0°E, 11.5°N). According to the analysis of the data from 18 ionospheric stations, Guangzhou Observatory is at the north crest of the double-crest where f0F2 reaches its maximum value. During high solar activity years, the maximum value of f0F2 in the diurnal variation occurs even at night-time, in addition, the occuring frequency of the ionospheric disturbances is higher than that of other observatories in China. These characteristics are all considered as the anomalies of the equatorial F2-layer.
Distinguish of the propagation Modes in the HF Backscattering Soundings
Huang De-yao
1987, 7(2): 139-145. doi: 10.11728/cjss1987.02.139
Abstract(1409) PDF 440KB(876)
Abstract:
In this paper, the occurrence and their features of the various propagation modes in the HFbackscattering are discussed. Some methods of distinguishing the propagation modes and the application of these methods in practical soundings are also presented.
A Method Estimating the Integral Mean Value of Enhancement Factor and the Path Latitude for the Whistlers Below Magnetic Latitude 10°
Wang You-shan
1987, 7(2): 146-153. doi: 10.11728/cjss1987.02.146
Abstract(1448) PDF 552KB(642)
Abstract:
The propagation of whistler-mode waves in the ionosphere is assumed to be the ducted propagation. In other words, the waves will be presumed as travelling along magnetic field lines. An analytic solution of the whistler dispersion equation is obtained in terms of the electron density models of the ionosphere the transverse gradient of the electron density required for guiding of whistler-mode waves along a magnetic field line, and an empirical formula for the magnetic field lines of 1980's IGRF (n = 8). In this paper, the electron density enhancement factor is defined as Nc/Ng-l (the Nc is the electron density at the centre of duct; the Ng is the background electron density at the latitude that is what the centre of duct lies). Thus, the integral mean value of the enhancement factor required and the path latitude (i.e. the exit point latitude of whistlers) can be analytically determined by a set of observed values: NmF2 and hmF2 of the ionosphere, and D (whistler dispersion). Using the data of D, NmF2 and hmF2 in Hainan Island of China, The above evaluation and come to the following conclusions are made. (1) The integral mean value of the enhancement factor required for ducting of low-latitude whistlers ranges from 7% to 31%. (2) The whistler dispersion Dhas a positive correlation with NmF2; and a negative correlation with hmF2 when the parth latitude φ90≤10.5° (IGRF, n = 8). Conversely, if (φ90>12° (IGRF, n=8) Dhas a positive correlation with hmF2. It is found that 94.5% of the whistlers observed at Sanya (18.24°N, 109.5°E; geomag. lat. 7.04°N; IGRF, n = 8, lat. 9.64°N) of Hainan Island have their path latitudes φ90<10.5°. Therefore, Dshould have a negative correlation with hmF2, which is agreeable to observations.
Treatment of Ionospheric Valley for the Laminar Reduction Method of Ionogram
Zhang Ren-fang
1987, 7(2): 154-162. doi: 10.11728/cjss1987.02.154
Abstract(1358) PDF 540KB(836)
Abstract:
This paper presents a method for the reduction of the ionospheric profile by using ordinary traces. The height of the Flayer bottom is determined by Gulyaeva's empirical equation. The ionospheric valley between Eand Flayers is an equivalent slab layer. The true-height reduction of the Flayer is based on Budden's method. The results of the reduction are compared with the profiles provided by Herbert. The error of true height is generally less than ±10 km for the middle latitudes.
Inner Boundary of the Heliosphere
Zhao Xue-pu
1987, 7(2): 163-165. doi: 10.11728/cjss1987.02.163
Abstract(1530) PDF 226KB(951)
Abstract:
There is no extensively accepted definition for the inner boundary of the heliosphere although the nomenclature——heliosphere——is increasingly used in the scientific presentations inthe space physics. After commenting some definitions of the inner boundary, the alfvenic points are suggested to be the inner boundary of the heliosphere. The definition is consistent with the concept of the wind sphere, and convenient for determination of the angular momentum loss of the Sun by the solar wind.
The Influence of Solar Flare and Nuclear Tests on 14C Concentration in Atmosphere
Dai Kai-mei
1987, 7(2): 166-168. doi: 10.11728/cjss1987.02.166
Abstract(1398) PDF 286KB(659)
Abstract:
The 14C content in 1940-1967 rings of a white spruce grown in Mackenzie Delta (68°N, 130°W) was measured in order to see if solar flare and nuclear tests could cause any measurable variation of 14C concentration in the atmosphere. The results are presented and discussed.