Influence of bounce resonance effects on the cyclotron wave instabilities in dipole magnetospheric plasmas with anisotropic temperature (original) (raw)
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We derive the expression for the ponderomotive force in the real multicomponent magnetospheric plasma containing heavy ions. The ponderomotive force considered includes the induced magnetic moment of all the species and arises due to inhomogeneity of the traveling low-frequency electromagnetic wave amplitude in the nonuniform medium. The nonlinear stationary force balance equation is obtained taking into account the gravitational and centrifugal forces for the plasma consisting of the electrons, protons and heavy ions (He +). The background geomagnetic field is taken for the dayside of the magnetosphere, where the magnetic field have magnetic "holes" (Antonova and Shabansky 1968). The balance equation is solved numerically to obtain the nonlinear density distribution of ions (H +) in the presence of heavy ions (He +). It is shown that for frequencies less than the helium gyrofrequency at the equator the nonlinear plasma density perturbations are peaked in the vicinity of the equator due to the action of the ponderomotive force. A comparison of the cases of the dipole and dayside magnetosphere is provided. It is obtained that the presence of heavy ions leads to decrease of the proton density modification.
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Journal of Geophysical Research, 1993
The parametric interaction of waves with particle cyclotron motion has been studied. A wave with a compressional magnetic field component modifies the cyclotron motion of the particles, which enables them to resonate with other waves which have perpendicular electric fields. Resonance occurs when the frequency difference of the two wave modes (compressional and perpendicular) matches the cyclotron frequency. This so-called parametric cyclotron resonance mechanism can provide a means to exchange energy between particles and low-frequency waves. We discuss the specific example of energy exchange between an Alfv6n wave and ion Larmor motion. Harada and G. K. Crawford for their useful comments.
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The formation of a zone of energetic electron precipitation by the plasmapause, a region of enhanced plasma density, following energetic particle injection during a magnetic storm, is analyzed. Such a region can also be formed by detached cold plasma clouds appearing in the outer magnetosphere by restructuring of the plasmasphere during a magnetic storm. As a mechanism of precipitation, wave-particle interactions by the cyclotron instability between whistler-mode waves and electrons are considered. In the framework of the selfconsistent equations of quasi-linear plasma theory, the distribution function of trapped electrons and the electron precipitation pattern are found. The theoretical results are compared with experimental data obtained from NOAA satellites.
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Le Journal de Physique Colloques, 1979
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Australian journal of …, 1993
Nonlinear modifications in the refractive indices of quasicircular electromagnetic waves, propagating obliquely in a cold homogeneous magnetised plasma in the presence of the Corio lis force of rotation, have been theoretically investigated. Some interesting properties are found to occur, which depend on the gyrofrequency, rotational frequency and the amplitudes of the waves. The characteristic variations of the refractive indices of the left and right circularly polarised waves, for different values of the gyrofrequency and rotational frequency, are shown graphically. The stop-bands, which are located for both the waves in the presence of the Coriolis force, are discussed. The stability criteria of the waves interacting with a plasma are also investigated. The results obtained are more general than those reported previously.