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1.
The existence of prolonged periods of abnormally low solar activity (such as the Maunder minimum) is explained within the framework of Leighton's model of a solar cycle with a hypothetical internal magnetic field of the Sun taken into account. 相似文献
2.
A standard pair of equations is used to describe the behaviour of a single monoenergetic particle (proton or electron) population on a geomagnetic flux tube drifting in the magnetosphere. When particle losses from the drifting flux tube into the ionosphere are neglected, this behaviour is adiabatic in a thermodynamic sense. For a population of particles with an isotropic pitch-angle distribution, the generalization of that system of equations is obtained by adding radial and azimuthal spatial diffusion terms. The magnetic field is taken to be dipolar in the inner magnetosphere. The potential electric field is assumed to consist of magnetospheric convection and corotation components. Experimental data are used to estimate the radial equatorial profiles of the plasma sheet pressure. Assuming that the local time and L-shell variations are separable and supposing steady-state conditions, the expressions for the diffusion tensor components are evaluated. The influence of spatial diffusion on the radial and azimuthal profiles of the plasma pressure in the inner plasma sheet is also discussed. 相似文献
3.
The trajectories of plasma-sheet protons are computed numerically in magnetic-field models which simulate the neutral-sheet-type configuration observed in experiments. No electric field is included, in contrast with the reconnection theory. Entering the neutral sheet and then exiting from it, the particle performs an ordered displacement across the tail. A continuous interchange between the neutral and plasma sheets will give rise to an electric current which may be responsible for the observed magnetic-field configuration. An estimate of this current is made from the tension balance requirement, showing that a substantial anisotropy of the plasma-sheet pressure is necessary to maintain the steady state. It is shown that the neutral sheet itself can be a source of such an anisotropy, due to the non-adiabatic behaviour of protons. Other anisotropy origins are discussed briefly. 相似文献
4.
Relationship between the geoefficiency of the solar flares as well as of the active regions passing the central meridian of the Sun and the configuration of the large scale solar magnetic field is studied.It is shown that if the tangential component of the large scale magnetic field at the active region or at the flare region is directed southwards, that region and that flare produce geomagnetic storm. In case when the tangential magnetic field is directed northward, the active region and the flares occurring at that region do not cause any geomagnetic disturbance.An index of the geoefficiency of the solar flares and of the active regions is proposed. 相似文献
5.
A method of separating electric field in the flare region in the potential and vortex (induced) parts is discussed. According to the proposed model, the motion of flare ribbons from the central line of the flare region is caused by the vortex component of the coronal electric field, while the motion of bright spots within the flare region towards the central line is driven by the potential component of that field. The intensity of both the components of the flare region electric field is estimated to equal approximately 1–3 V cm–1, which provides the input of the electromagnetic energy into the active region at a rate of about 1010 erg cm–2 s–1. 相似文献
6.
Adiabatic indices for a non-dissipative anisotropic convecting plasma are analyzed, and general expressions for the effective adiabatic index and the partial adiabatic indices parallel (γ∥) and perpendicular (γ⟂) to the magnetic field are obtained. It is shown that, in the general case, the value of the effective adiabatic index is not an universal constant and depends on the plasma temperature anisotropy and on the properties of the plasma motion. The values of γ⟂ and γ∥ are shown to be independent of the plasma parameters being completely determined by the characteristics of the plasma flow. 相似文献
7.
Bruno P. Besser Mikhail I. Pudovkin Valentina V. Lebedeva Svetlana A. Zaitseva Claudia-Veronika Meister 《Astrophysics and Space Science》2000,274(1-2):399-405
Variations of the magnetic field and plasma parameters across the Earth's magnetosheath are calculated for an anisotropic
plasma in the Chew-Goldberger-Low approximation. Additionally, proton pitch-angle diffusion is taken into account as the energy
transfer mechanism between the direction perpendicular and parallel to the magnetic field. We discuss the main characteristics
of the magnetic barrier for different temperature relaxation times and their dependence on the interplanetary magnetic field
orientation.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
M.I. Pudovkin S.A. Zaitseva T.A. Bazhenova V.G. Andrezen 《Planetary and Space Science》1985,33(4):407-414
A model for solar wind flow around the magnetopause incorporating a stagnation line at the frontside magnetopause is used to derive a formula for the electric field intensity and polar cap potential drop. These relationships are compared to experimental data from polar orbiting satellites. The relation between solar wind parameters and auroral arc velocity is also studied. 相似文献
9.
The rate of energy input to the ring current is studied as a function of solar wind parameters. The ring current dissipation rate is also examined. The decay constant τ in the main phase of a storm has been shown to be independent of its intensity and to equal (4 ± 2) h. In the recovery phase τ rises with increasing storm intensity. 相似文献
10.
On the basis of the geomagnetic data of highlatitude arctic stations the development of polar magnetic substorms is examined. It is shown that there exist two current systems of the magnetic substorm: DP11 and DP12. 11 is a current system with one westelectrojet in the nighttime auroral zone. That system is peculiar to the break-up phase of a substorm. DP12 is a two-vortex current system in the polar cap with two auroral electrojets, eastward and westward, of about equal intensity. The DP12 system is typical for growth and recovery phases.There are two different types of substorm development. The first type is characterized by the DP12 system during the growth phase. The intensity of this current system increases until the explosive phase begins. The other type does not seem to be characterized by any distinct current system during the growth phase. The commencement of such a substorm is associated with a rapid explosive development of the DP12 system.A conclusion about the the different origins of the DP11 and DP12 current systems is made. 相似文献