Collective laser light scattering from thermal fluctuations in a collision dominated plasma

The influence of collisions on the ion feature was investigated in a hydrogen plasma using collective laser light scattering. For partial ionization increasing values of the ion-neutral collision frequency were shown to lead to a damping of the ion acoustic resonance and to a narrowing of the central line in the spectrum. In contrast, for complete ionization ion-ion collisions enhance the ion acoustic resonance.