INTERNATIONAL JOURNAL OF GEOMAGNETISM AND AERONOMY VOL. 7, GI3004, doi:10.1029/2006GI000164, 2008

Slow magnetosonic oscillations with m >> 1 in a dipole magnetosphere with rotating plasma

Institute of Solar-Terrestrial Physics, Irkutsk, Russia

Abstract

[1]  A mechanism of excitation of azimuthal small-scale (m >> 1) slow magnetosonic (SMS) oscillations by the external currents in the near-equatorial region of the terrestrial magnetosphere is proposed. A theoretical study of the structure and spectrum of such oscillations is performed in the model of the magnetosphere with the dipole magnetic field and rotating plasma. In the direction along field lines of the geomagnetic field the oscillations are waves standing between the magnetically conjugated points. The amplitude of the magnetospheric SMS oscillations with m >> 1 decreases from the equatorial plane to the ionosphere at scales much lower then the field line length. So one is not able to observe the SMS-oscillation field in the vicinity of the ionosphere and on the surface of the Earth. In the direction across the magnetic shells, the standing SMS waves have a structure typical for resonant oscillations. Latitudinal distributions of eigenfrequencies of several first harmonics of SMS oscillations with the polarization similar to the polarization of poloidal and toroidal Alfvén waves in the plane perpendicular to the field lines are drawn.

Received 25 September 2006; revised 11 October 2007; accepted 14 February 2008; published 8 March 2008.

Keywords: Slow magnetosonic oscillations; Dipole-like magnetosphere; Structure of resonant SMS oscillations.

Index Terms: 2740 Magnetospheric Physics: Magnetospheric configuration and dynamics; 2736 Magnetospheric Physics: Magnetosphere/ionosphere interactions; 2799 Magnetospheric Physics: General or miscellaneous.

Citation: Kozlov, D. A. (2008), Slow magnetosonic oscillations with m >> 1 in a dipole magnetosphere with rotating plasma, Int. J. Geomagn. Aeron., 7, GI3004, doi:10.1029/2006GI000164.