NONLINEAR ION-CYCLOTRON RESONANCE IN ELECTROMAGNETIC-WAVE WITH NONUNIFORM AMPLITUDE

The cyclotron motion of ion in a nonuniform electromagnetic wave is an alysed using the multiple-time-scale-expansion method. A set of nonlin ear equations which describes the evolutions of the gyroradius rho, th e gyrophase beta, and the average velocity (nu(z)) along the magnetic field B-0 is obtained. The set is found exactly integrable and three c onservation relations are obtained for an arbitrary harmonic among rho , beta, <nu(z)> and the drift coordinates perpendicular to Be. The the ory includes the one obtained for the fundamental harmonic and a unifo rm amplitude wave and is also applied to ion acceleration in a non-uni form held near an antenna used in an ion-cyclotron-range-of-frequencie s (ICRF) wave heating. Thus the theory seems to be more rigorous and g eneral than the previous ones.