Scattering cross section of electromagnetic waves in turbulent plasmas

Scattering of electromagnetic waves by plasma is a very successful plasma diagnostic technique. The calculation of the differential cross section for the scattering of an electromagnetic wave by a totally ionized plasma can yield plasma parameters including different electron and ion temperatures, uniform stationary magnetic field and a relative drift velocity between electrons and ions. Here we consider the role strong high frequency electron plasma wave turbulence plays in the scattering process. Electron plasma wave turbulence can undergo the modulational instability resulting in wave collapse and cavity formation. The modulational instability changes the dispersive properties of low frequency ion acoustic modes by introducing both a real frequency shift as well as an imaginary frequency which can either be growth or damping of the low frequency mode. The effects of the electron plasma wave turbulence on damping the low frequency ion acoustic response can also have a significant effect in stabilizing instabilities. Using a wave kinetic treatment, we calculate a susceptibility term due to turbulence resulting in corrections to the scattering form factor.