Evolution of laser pulse shape in a parabolic plasma channel

Abstract

During high-intensity laser propagation in a plasma, the group velocity of a laser pulse is subjected to change with the laser intensity due to alteration in refractive index associated with the variation of the nonlinear plasma density. The pulse front sharpened while the back of the pulse broadened due to difference in the group velocity at different parts of the laser pulse. Thus the distortion in the shape of the laser pulse is expected. We present 2D particle-in-cell simulations demonstrating the controlling the shape distortion of a Gaussian laser pulse using a parabolic plasma channel. We show the results of the intensity distribution of laser pulse in a plasma with and without a plasma channel. It has been observed that the plasma channel helps in controlling the laser pulse shape distortion. The understanding of evolution of laser pulse shape may be crucial while applying the parabolic plasma channel for guiding the laser pulse in plasma based accelerators. © 2016 Astro Ltd.