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- Title
Dispersion relation for ballooning modes and condition of their stability in the near-earth plasma.
- Authors
Mazur, N.; Fedorov, E.; Pilipenko, V.
- Abstract
The ballooning disturbances in a finite-pressure plasma in a curvilinear magnetic field are described by a system of coupled equations for Alfvén and slow magnetosonic modes. The local dispersion relation obtained in a WKB approximation is the simplest and most evident method that can be used to characterize the properties of these disturbances. This dispersion relation is widely used to predict the possible instabilities and spectral properties of LF oscillations in the nightside magnetosphere. The formal derivation of the dispersion relation from the initial system of coupled MHD modes and the transition to different limiting cases have been traced. The behavior of dispersion curves in different oscillation branches and the possible development of instabilities and formation of regions where waves cannot propagate have been studied in detail. This made it possible to specify the results of previous works and even indicate the incorrectness in some works. In particular, it has been indicated that a fast Alfvén branch of oscillations is always stable and an aperiodic instability can originate on a slow magnetosonic oscillation branch.
- Subjects
MAGNETIC fields; DISPERSION relations; MAGNETOSPHERE; PARTICLES; MAGNETOHYDRODYNAMIC waves
- Publication
Geomagnetism & Aeronomy, 2012, Vol 52, Issue 5, p603
- ISSN
0016-7932
- Publication type
Article
- DOI
10.1134/S0016793212050118