Observation of Parametric Instabilities at Unstable Electrostatic Ion Cyclotron Waves in an Ion Beam-Plasma System

Abstract

We have observed experimentally the parametric excitation of ion acoustic waves and electrostatic ton cyclotron waves by hf electric fields with frequencies of unstable electrostatic ion cyclotron waves. The resonant condition is satisfied, and the decay waves are amplified exponentially by increasing the amplitude of the pump wave. The growth rate of the decay waves and the threshold of pump hf electric fields measured experimentally is compared with the theory.