Plasma Resonances of the Magnetosphere

Abstract

THERE have been many investigations of resonance phenomena in geophysics, for example, the Schumann resonances of the Earth-ionosphere cavity which is excited by lightning flashes. Theoretical attempts have been made to determine possible hydromagnetic resonances of the magnetosphere which should be excited by the solar wind. Under conditions of axial symmetry it is possible to obtain uncoupled solutions for poloidal and toroidal modes. Carovillano and Radoski¹ have recently considered a perfectly conducting plasma, magnetized by a dipole field, in which the plasma density function was expressed in a generalized form, thus allowing their model to incorporate some of the observed features of the magnetosphere. Their calculations for the toroidal modes, and also for the poloidal modes, indicate that the eigen-periods for such a model magnetosphere should lie in the geomagnetic micropulsation range, in agreement with the conclusions reached by a number of other workers.