Transition from wakefield generation to soliton formation

TL;DR

This paper investigates how increasing plasma density shifts laser pulse behavior from wakefield generation to soliton formation, using a 1D relativistic cold fluid model and particle-in-cell simulations, revealing maximum energy loss at 10% of critical density.

Contribution

It introduces a detailed analysis of the transition from wakefield to soliton formation in plasma as density increases, combining fluid and particle simulation methods.

Findings

Maximum energy loss occurs at ~10% of critical density.

Wakefield generation is sharply suppressed at higher densities.

The transition to solitons is characterized by nonlinear self-modulation.

Abstract

It is well known that when a short laser pulse propagates in an underdense plasma, it induces longitudinal plasma oscillations at the plasma frequency after the pulse, typically referred to as the 'wakefield'. However, for plasma densities approaching the critical density wakefield generation is suppressed, and instead the EM-pulse undergoes nonlinear self-modulation. In this article we have studied the transition from the wakefield generation to formation of quasi-solitons as the plasma density is increased. For this purpose we have applied a one dimensional (1D) relativistic cold fluid model, which has also been compared with particle-in-cell simulations. A key result is that the energy loss of the EM-pulse due to wakefield generation has its maximum for a plasma density of the order 10 percent of the critical density, but that wakefield generation is sharply suppressed when the density is increased further.