Non-relativistic free–free Gaunt factors in Debye plasmas

ABSTRACT To well predict the emitted spectrum of ionized plasmas, the modern spectral synthesis codes need thermally averaged free–free Gaunt factors in a wide plasma temperature and density range. However, the plasma screening effects on the Gaunt factors have rarely been studied and taken into account in the emission calculations. In this work, we comprehensively investigate the free–free absorption Gaunt factors with the inclusion of plasma screening effects for weakly coupled (Debye) plasmas, met in the stellar atmospheres and their interiors and in the inertial confinement fusion research. The free–free Gaunt factors are presented over a wide range of screening lengths, covering the energy parameter space log10εi(Ry) = −8 to +8 and log10ωi(Ry) = −8 to +8. The temperature-averaged (over the Maxwellian electron energy distribution) Gaunt factors, as well as the frequency integrated Gaunt factors, are presented for a number of screening lengths in the range 10–500 a.u., and covering the parameter space log10γ2 = −4 to +6 and log10u = −4 to +12.