Properties of Electrostatic Ion-Cyclotron Waves in a Mirror Machine

Abstract

Frequency and wavelength of electrostatic ion-cyclotron waves have been measured in a mirror machine. The dominant frequency occurs near the ion-cyclotron fundamental with width $\frac{\ensuremath{\Delta}f}{f}<0.02$. For most of the plasma buildup and decay the perpendicular wave numbers are consistent with an ion-diamagnetic drift wave ${{\ensuremath{\omega}}_{i}}^{*}={k}_{\ensuremath{\perp}}(\frac{c{E}_{i}}{\mathrm{cB}})(\frac{1}{n})\frac{\mathrm{dn}}{\mathrm{dx}}$ at the ion-cyclotron frequency. With increasing wave amplitude the wave spectral properties do not change but an increase in ion energy diffusion is observed, supporting a wave-particle saturation of the mode.