Free-free Gaunt factor for dense low temperature plasmas

Abstract

In dense low temperature plasmas, electrostatic correlations affect the interaction between charged particles. This means that the usual hypothesis of the majority of the plasmas theories ln Lambda >>1 or ne lambda D3<<1 does not hold. The complex part of the refractive index of such a plasma, which is related to the free-free absorption is shown to be sensitive to this so called 'non-ideality' effect, estimated using the kinetic transport theory. Results are given in the form of a Gaunt factor for which simple analytical expressions are deduced. As is the case for the d.c. conductivity, important discrepancies appear, depending on the type of small ln Lambda correction used.