The drift-cyclotron instability of plasma in an inhomogeneous high frequency field

A study is made of the effect of a skin high frequency field polarized along the magnetostatic field, on the onset of the drift-cyclotron instability of an inhomogeneous plasma with warm ions. It is found that an h.f. field of this sort removes instability on the low harmonics of the ion cyclotron frequency but that instability arises on all the higher harmonics.