Journal cover Journal topic
Annales Geophysicae An open-access journal of the European Geosciences Union
Ann. Geophys., 24, 2277-2289, 2006
© Author(s) 2006. This work is distributed
under the Creative Commons Attribution 3.0 License.
13 Sep 2006
Magnetosonic resonance in a dipole-like magnetosphere
A. S. Leonovich1, D. A. Kozlov1, and V. A. Pilipenko2 1Institute of Solar-Terrestrial Physics (ISTP), Russian Academy of Sciences, Siberian Branch, Irkutsk, Russia
2Institute of the Physics of the Earth, Russian Academy of Sciences, Moscow, Russia
Abstract. A theory of resonant conversion of fast magnetosonic (FMS) waves into slow magnetosonic (SMS) oscillations in a magnetosphere with dipole-like magnetic field has been constructed. Monochromatic FMS waves are shown to drive standing (along magnetic field lines) SMS oscillations, narrowly localized across magnetic shells. The longitudinal and transverse structures, as well as spectrum of resonant SMS waves are determined. Frequencies of fundamental harmonics of standing SMS waves lie in the range of 0.1–1 mHz, and are about two orders of magnitude lower than frequencies of similar Alfvén field line resonance harmonics. This difference makes an effective interaction between these MHD modes impossible. The amplitude of SMS oscillations rapidly decreases along the field lines from the magnetospheric equator towards the ionosphere. In this context, magnetospheric SMS oscillations cannot be observed on the ground, and the ionosphere does not play any role either in their generation or dissipation. The theory developed can be used to interpret the occurrence of compressional Pc5 waves in a quiet magnetosphere with a weak ring current.

Citation: Leonovich, A. S., Kozlov, D. A., and Pilipenko, V. A.: Magnetosonic resonance in a dipole-like magnetosphere, Ann. Geophys., 24, 2277-2289, doi:10.5194/angeo-24-2277-2006, 2006.
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