Heating of electrons and ions by inverse bremsstrahlung absorption: a self-similar tate of the plasma

It is shown that, under the influence of a monochromatic HF electric field (laser beam), both the electrons and the ions in a high-Z plasma reach a homogeneous and isotropic self-similar state (SSS) in which the distribution functions are of the factorized form: where W±(t) is a scaling velocity, the square of which is proportional to the effective temperature. Whereas the SSS for the electrons was known from previous work, with

it is shown here that the corresponding ion SSS exists and is characterized by a simple Maxwellian, øi ø exp (-v²). The discussion of the thermal velocities W±(t), which are obtained in analytical form, provides a transparent physical insight into the heating mechanism of the plasma by inverse bremsstrahlung absorption.