Plasma diagnostics based on coherent four-photon scattering of light by ionic sound

A theoretical proposal is made of a method for diagnostics of a low-temperature plasma. This method is based on coherent four-photon scattering of light and its advantage over the usual Thomson scattering is the enormous enhancement of the scattering signal, which depends on the intensities of the pump beams. The method can be used to determine the electron density, damping coefficient of ionic sound, and electron temperature of a plasma.