Nonlinear phenomena at ion cyclotron resonance in a plasma

Theoretical and experimental work on nonlinear phenomena at ion cyclotron resonance in a plasma is reviewed. Questions associated with the nonlinear interaction of resonant ions with waves at ICR are discussed: stochastic cyclotron acceleration of particles by the waves in a nonuniform magnetic field, in particular, cyclotron heating in a tokamak; trapping of particles by waves; nonlinear resonance at half-integer harmonics of the cyclotron frequency; and autoresonant cyclotron acceleration of ions. The instabilities of a plasma in strong pump fields with frequencies near or on the order of the cyclotron frequency are discussed: the lower hybrid beam, ion acoustic, electron acoustic, ion-ion, and parametric ion cyclotron instabilities. Plasma turbulence which results from these instabilities and turbulent heating of the plasma are discussed.