Abstract: In this paper the 9 days meaned series of the dayly international sunspot numbers from 1932-1982 are used to analyse the dynamical properties of the sunspots evolution. It is concluded that the sunspot is a complex dynamical system which should be described by at least seven independent variables, and that its correlation dimension is 6.3 ± 0.1, the 2-order Renyi entropy and the maximum Lyapunov exponent are respectively (0.37 ±0.02) bit/yr. The predictable time scales that they indicate, namely, the time for initial error becoming 2 times larger, are (2.7±0.2) years and (2.9±0.1) years, respectively.
Abstract: In this paper, a storm model is presented taking the magnetic field ecolution of a coronal active region as the driving force of the noise storm phenomena. And it has been assumed that a coronal active region is inhomogeneous in magnetics, there are" strong magnetic field fibers in it. The evolution of the magneic structure of an active region will produce weak shocks. When the shocks pass a coronal arch, a fraction of electrons is heated. The, heated fast electrons form a local loss-cone distribution in strong magnetic fibers. The fast electron loss-cone instabilities will generate Langmuir wave and whistler wave with high temperature. When the Langmuir wave spectrum slip towards smaller wave number ranges due to differential transfer, it will strongly act with whistler wave to produce electromagnetic wave with high frequency in a narrow beam (type-1 buist). Astrong field and associated configuiation determine the frequency band width and duration of a type-1 burst. And continuum is due to the coupling between the Langmuir wave from a fast electron isotropic distribution and an other low frequency wave.It is thought that the strong directivity of type-1 bursts is the intrinsic characteristics of them. To distinguish which low frequency disturbance will couple with a high frequency wave to generate a trasverse electromagnetic wave, the directivity should be referred to as a critical factor. And that is one of the differences of this model from others.
Abstract: Based on the ideal magnetohydrodynamics, the present paper discusses the linear stability of a semicircular electric current sheet tied at the photoshere. The main conclusion is that the electric current sheet becomes unstable if the magnetic field component in the direction of the electric current is less than a certain critical value. Furthermore, the wave number of the disturbance in the current direction, which causes the instability first, is approximately the reciprocal of the diameter of the current sheet circle.
Abstract: Z-component of geomagnetic measurements of 1983-1984 from several low-latitudinal stations are used for further study of the effect of the large scale magnetospheric disturbance on the equatorial electrojet. Data presented in this paper are from India (TRI, KOD, ANN, ...) and China (Qiong Zhong, ...). The results of event analysis and superposed epoch analysis confirm the conclution deduced by the same authors in a previous paper using the Chinese data only, i.e. corresponding to the development of the ring current in the magnetosphere, there is a negative perturbation AZ (it means an additional eastward electrojet). The contrast between the results from a pair of stations of different longitudes and the local time distribution of AZshows that the effect is strongest at daytime and weakest from midnight to dawn. It is basically in accordance with the model calculation of the authors. The results also prove the idea that in analysing the variation of the equatorial electrojet on disturbed days, one should distinguish the effects occured at different storm phases, and draw a distinction between the effects of dynamic and electrodynamic couplings, In order to ascertain the local time and the longitudinal variations of the effect, analyses for simultaneous measurements of global distributed stations are necessary.
Abstract: Prediction test for 40 geomagnetic disturbance events caused by the flare-associated interplanetary shock waves, which can be identified by interplanetary scintillation (IPS) observations during 1984-1985, are made based on the membership functions established by using observational data on the solar flares, the interplanetary shock waves and the geomagnetic disturbances during the period of 1966-1982. Main results are: (1) Prediction of the magnetic disturbance onset time-for 50% of all events, the relative error, δT/T≤10%; and for 70%,δT/r≤20%; (2) Prediction of the geomagnetic disturbance amplitudes-for 80% of allevents, the relative error, δ∑Kp/∑Kp≤30% ; and only for 15%, δ∑Kp/∑Kp≥60%. These results show that the method adoption in this paper has some potential prospects for investigating the flare-associated interplanetary shock waves and the geomagnetic disturbance predictions.
Abstract: In this paper, using ionosonde data in Urumqi, Lanzhou, Beijing, Changchun, Manzhouli, Chongqing and Hainan of China and Wakkanai, Akita, Kokubunji, Yamagawa and Okinawa of Japan and simultaneously observed data of the geomagnetism, cosmic rays, TECand ionosphere during the magnetic storm in 1983-1985, various variation of the occurrence rate of the particle Eare presented. These variations obviously are shown that:(1) The events of the particle Eoccur mainly during the main phase and expansive phase of the magnetic storm. The occurrence rate of the particle Ehas a close correlation with the magnetude of the decreasing of the equatorial ring current index (Dst-index), but is not connected with the magnetic storm's type (sudden-commencement or gradual-commencement).(2) The monthly variation of the occurrence rate of the particle Eis the most in the spring, little in the summer.(3) The diurnal variation of the occurrence rate of the particle Eis more at midnight than at earlier midnight.(4) TECalways sharply increases during the events of the particle E.(5) The maximum occurrence rate of the particle Eis above 30 degrees of the geomagnetic latitude in China, above 25 degrees of the geomagnetic latitude in Japan.In addition, it i5 supposed that the precipitation particle may be the main cause for theevents of the particle Ein the low-latitude region.
Abstract: The purpose of the paper is to give a brief introduction to the atmospheric and ionospheric models of MSIS-86 and IRI-86 and to deduce the thermospheric wind system, the spacial distribution and temporal variation of collision frequencies and ionospheric conductivities, which are important parameters in the research of thermosphere-ionosphere coupling. The model parameters used are different from that of the old models in many cases. For instance, the maximum temperature at 300km altitude is nearly to 80°Nfor winter solstice condition according the MSIS-86 model, while it appears at 23.5°Nin the Jacchia-77 model. Since a lot of new data from DE-Bsatellite flying across polar region are involved in the new model, the temperature distribution presented here is more reliable, especially at high latitudes.The main results from the model calculations given in this paper are the following:1. Generally, the thermospheric wind flows from daylit hemisphere to night side. The air flows longitudewards at noon-midnight meridian (northward at noon and southward at midnight) during the year of sunspot minimum, but is across the longitude at other meridians. At sunspot maximum, however, the wind blowing along a longitude line occurs at 2:00-14:00 LTmeridian, i.e. 30° degree of longitude from the location of maximum heating by solar radiation.2. Strong southward component of the wind velocity appears at high latitudes during magnetic disturbed days as a result of particle precipitation and Joule heating.3. On cursory examination, the conductivity distribution calculated from MISI-86 and IRI-86 is similar to that got by Maeda et al., nevertheless various important details are added. Therefore, recalculation of the conductivity for different special conditions (i.e. time, place, solar and geomagnetic activity etc.) is necessary for the further study of the thermosphere-ionosphere coupling.In brief, this work tries to set up a link between the model based on observations and the study based on theory. Since thte models only present the average situation, the application confined to the macroscopic research and analysis of the phenomena of large scale.
Abstract: The measurements of the parameters of an afterglow plasma produced by modulated pulse discharge have shown that the decay of the space potential and electron temperature is important in studying electron density decay processes in afterglow plasmas. This must not be ignored. Measurements of the radial distribution of the electron density at the 60 us of the afterglow time are quite in agreement with the theoretical predictions.
Abstract: The dispersion equation of linear disturbance magnetohydrodynamics equations is an algebraic equation of third power of frequency when the magnetic diffusivity is considered as a function of temperature. Developing dispersion equation with small parameter ε = u02/us2, the square of disturbing velocity over sound speed, and taking the zero order approximation of e, the magnetic diffusion instability can be obtained when the dispersion equation is solved.In this paper, the influence of small flows on the magnetic diffusion instability is discussed under the first order approximation of ε. The solution appears that it does not lose the magnetic diffusion instability with the existance of small flows in the dispersion equation and there are a few influence of small flows on the area of the magnetic diffusion instability in the wave number space.
Abstract: The paper analyses the data of received Omega Signals from Gstation, at Xinxiang and Lanzhou respectively. It is worth especially noting that two receivers, which are adjusted in the optimum operating conditions, are used to simultaneously receive the signals at Xinxiang.The experimental results show that the measured phase cycle loss is a kind of propagation phenomenon during VLFsignal travelling. And together with the measurement result at Lanzhou, the reason for this phenomenon may be analysed forther.