The flute instability of a plasma driven by the electrostatic high-frequency eigenmodes

Expressions for the electron drift velocity in a plasma with excited electromagnetic high-frequency eigenmodes are derived in WKB approximation. Contributions from the time-averaged electron motion in the electric field both of the high-frequency eigenmode and of the low-frequency perturbation are included. Further, the flute instability arising from the electron drift is studied numerically. The dependence of the maximum instability growth rate on the amplitude of the electric field of eigenmodes is given graphically. Since higher-order eigenmodes are unstable only for the short-wave perturbations, they can be used for suppression of the flute instability. (J.U.)