THE EFFECT OF EXTERNALLY APPLIED OSCILLATING ELECTRIC-FIELDS ON THE L=1 AND L=2 DIOCOTRON MODES IN NONNEUTRAL PLASMAS

A high-frequency oscillating electric field can change the properties of diocotron modes in non-neutral plasmas. The effect depends crucially on the azimuthal mode number, m, of the applied field. For m = 0, ± 1 there is no effect, and for applied standing waves there is also no effect. But if the applied field has the form of a traveling wave with |m\>2, the frequency of stable diocotron modes can be modified and for |m|>3, the 1=2 instability of hollow density profiles can be stabilized. The analytic results are verified with a nonlinear fluid simulation of an infinitely long non-neutral plasma. © 1990 American Institute of Physics.