MHD-resonator in the front part of the magnetosphere and its excitation by extramagnetospheric hydromagnetic waves (monochromatic oscillations)

The one-dimensional inhomogeneous model of medium was applied to study theoretically the MHD-resonator properties in the front part of the magnetosphere (its eigenfrequencies and eigenmodes) and its excitation by monochromatic hydromagnetic waves incident on the magnetosphere from the solar wind. Damping factor of eigenmodes is determined by the absorption at Alfvén resonance points and by the radiation into the solar wind through the partially reflecting magnetopause. The magnetospheric resonator effect was demonstrated to result in the resonant behavior of the level of pumping of the magnetosphere by incident waves. Waves penetrate into the magnetosphere only in narrow spectral ranges near the resonator's eigenfrequencies whose width is of order of eigenmode damping factor. Waves with other frequencies are reflected from the magnetopause.