Bremsstrahlung from dense plasmas and the Landau-Pomeranchuk-Migdal effect

The suppression of the bremsstrahlung cross section due to multiple scattering of the emitting electrons is an important effect in dense media (Landau-Pomeranchuk-Migdal effect). Here, we study the emission from a dense, fully-ionized and non-relativistic hydrogen plasma. Using the dielectric approach, we relate optical properties such as emission and absorption to equilibrium force-force correlation functions, which allow for a systematic perturbative treatment with the help of thermodynamic Green functions. By considering self-energy and vertex corrections, medium modifications such as multiple scattering of the emitting electrons are taken into account. Results are presented for the absorption coefficient as a function of the frequency at various densities. It is shown that the modification of the inverse bremsstrahlung due to medium effects becomes more significant in the low frequency and high density region.