Toroidal resonance and cut off surfaces in the ion cyclotron frequency range

Resonances and cut off surfaces in the ion cyclotron regime were studied for a multicomponent plasma in an axisymmetric toroidal geometry. Three resonances appear: the fundamental ion cyclotron resonance, Buchsbaum ion-ion hybrid resonance, which is a resonance for the slow quasielectric wave, and the perpendicular ion cyclotron resonance, which is a resonance for the fast electromagnetic wave. The last mentioned resonance surfaces coincide with the magnetic surfaces. The cut off concept was generalized to be applicable to differential equations. A category of cut off surfaces are defined by the apparent singularities being independent of the gradient of the equilibrium quantities. The problem of finding resonance and cut off surfaces for an axially symmetric plasma was reduced to a problem of solving ordinary differential equations.