Influence of many-particle effects on spectral line shapes in nonthermal plasmas.

Abstract

A many-particle theory is applied to investigate the influence of plasma oscillations on spectral line profiles. Collective plasma modes in equilibrium plasmas are known to influence only the line shift, not the shape of spectral lines. In nonequilibrium plasmas, however, the frequency-dependent width of the line becomes resonant near the electron plasma frequency. Dips on the profile resulting from these resonances could be found calculating the ${\mathrm{L}}_{\mathrm{\ensuremath{\alpha}}}$ line profile. Their position and shape excellently agree with experimental results.