Dynamic polarizability and the theory of the ion-acoustic turbulence in a plasma containing ions of two species

Abstract

A damping rate of the induced scattering of fast ion-acoustic waves on ions, the explicit form of which depends on the plasma polarizability at the frequency of beats of the interacting waves, was determined for a nonisothermal plasma containing hot electrons and cold ions of two species. In the case of a plasma containing mobile light ions and slow heavy ions, a new phenomenon of significant decrease in the probability of induced scattering was established. This effect is related to the fact that a contribution to the dielectric function of slow ions, determining the scattering amplitude, depends on both spatial and frequency dispersion. It is shown that this decrease in the induced scattering probability leads to a growth of the turbulent noise level and to a change of the anomalous transport coefficients in the limit of large turbulent Knudsen numbers. The same effect is responsible for a relative decrease in the runaway electron production.