Simulation of laser pulse amplification in a plasma by a counterpropagating wave

Raman amplification of a short laser pulse by a counter-propagating pump in a plasma is simulated with a one-dimensional electromagnetic particle-in-cell code. With a large growth rate due to three wave interaction, the pump pulse is almost totally depleted and the seed pulse is amplified significantly by the transferred energy. A moving window is adopted to enhance simulation efficiency for long interaction length.