The ion cyclotron resonator in the magnetosphere

Our concern here is to present the idea of the ion cyclotron resonator in t he planetary magnetosphere and to discuss briefly the experimental status o f the corresponding theory. The resonator confines the ion cyclotron waves to a thin equatorial zone, so that it keeps the wave field from coming into contact with the ionosphere, resulting in a decrease in energy losses. The properties of the resonator are illustrated by adopting a plausible distri bution of the magnetic field in the equatorial zone, which yields an expres sion for the discrete spectrum of the waves just above the gyrofrequency of heavy ions. We show that the resonator is remarkable for many reasons, inc luding the frequency dependence of its size and specific structure of the s pectrum. (C) 2000 MAIK "Nauka / Interperiodica".