Propagation of Test Waves in the Presence of Ion Acoustic Turbulence in Plasmas

Abstract

Ion acoustic turbulence is excited by the current-driven ion acoustic instability in a dc discharge plasma. By measuring the dispersion relation of test waves in the plasma with the ion acoustic turbulence, we find that the wave energy transfers from high frequencies to low frequencies and the phase velocity of the ion acoustic wave becomes smaller than the ion acoustic velocity in low frequencies near the peak of the turbulence spectrum. These experimental results can be interpreted theoretically.