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Ann. Geophys., 24, 2291-2297, 2006
www.ann-geophys.net/24/2291/2006/
© European Geosciences Union 2006
Spatial structure and dispersion of drift mirror waves coupled with Alfvén waves in a 1-D inhomogeneous plasma
D. Yu. Klimushkin
Institute of Solar-Terrestrial Physics (ISTP), Russian Academy of Science, Siberian Branch, Irkutsk, 664033, Russia
Abstract. The paper employs the frame of a 1-D inhomogeneous model of space plasma,to examine the spatial
structure and growth rate of drift mirror modes, often suggested for interpreting some oscillation types in space
plasma. Owing to its coupling with the Alfvén mode, the drift mirror mode attains dispersion across magnetic
shells (dependence of the frequency on the wave-vector's radial component, kr). The spatial structure of a mode
confined across magnetic shells is studied. The scale of spatial localization of the wave is shown to be
determined by the plasma inhomogeneity scale and by the azimuthal component of the wave vector. The wave
propagates across magnetic shells, its amplitude modulated along the radial coordinate by the Gauss function.
Coupling with the Alfvén mode strongly influences the growth rate of the drift mirror instability. The mirror mode
can only exist in a narrow range of parameters. In the general case, the mode represents an Alfvén wave
modified by plasma inhomogeneity.
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