Raman Amplification in Plasma: Thermal Effects

The impact of thermal effects on Raman amplification in plasma is investigated theoretically. It is shown that damping and the shift in plasma resonance at finite temperature can alter the evolution of the amplified pulse and lead to pulse compression which is not predicted by the cold plasma model. Although thermal effects can lead to a reduction in the efficiency of the interaction, this can be ameliorated by using a chirped pump. In this case thermal effects can be beneficial and suppress the development of the train of pulses that develops behind the amplified pulse, as observed in the cold plasma model.