Laser pulse distortion in a plasma of the weakly relativistic regime

摘要

We present particle-in-cell simulations to demonstrate laser pulse distortion by incorporating the role of plasma electron temperature, where the laser pulse propagates in the weakly relativistic regime. A high-intensity laser pulse gives rise to a relativistic ponderomotive force on the electrons and redistributes the plasma density, so the refractive index of the plasma changes. The electron temperature also contributes to the nonlinearity and it results in distortion of the laser pulse. As the laser pulse becomes self-focused, the front part of the pulse acquires higher group velocity compared to the tail part. As a result, the laser pulse shape changes. Our simulation shows that the plasma electron temperature plays a key role in the laser pulse distortion phenomena in the weakly relativistic regime.