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Ann. Geophys., 24, 263-274, 2006
www.ann-geophys.net/24/263/2006/
© European Geosciences Union 2006
The structure of standing Alfvén waves in a dipole magnetosphere with moving plasma
D. A. Kozlov1,3, A. S. Leonovich1,3, and J. B. Cao2,3
1Institute of Solar-Terrestrial Physics (ISTP), Russian Academy of Sciences, Siberian Branch, Irkutsk, Russia
2Center for Space Science and Applied Research, Chinese Academy of Science, Beijing, China
3Russian-Chinese Joint Research Center on Space Weather
Abstract. The structure and spectrum of standing Alfvén waves were
theoretically investigated in a dipole magnetosphere with moving
plasma. Plasma motion was simulated with its azimuthal rotation.
The model's scope allowed for describing a transition from the
inner plasmasphere at rest to the outer magnetosphere with
convecting plasma and, through the magnetopause, to the moving
plasma of the solar wind. Solutions were found to equations
describing longitudinal and transverse (those formed,
respectively, along field lines and across magnetic shells)
structures of standing Alfvén waves with high azimuthal wave
numbers m>>1. Spectra were constructed for a number of first
harmonics of poloidal and toroidal standing Alfvén waves inside
the magnetosphere. For charged particles with velocities greatly
exceeding the velocity of the background plasma, an effective
parallel wave component of the electric field appears in the
region occupied by such waves. This results in structured
high-energy-particle flows and in the appearance of multiband
aurorae. The transverse structure of the standing Alfvén waves' basic
harmonic was shown to be analogous to the structure of a discrete
auroral arc.
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