Self-trapping and acceleration of ions in laser-driven relativistically transparent plasma

TL;DR

This paper investigates how ions can be trapped and accelerated in laser-driven relativistically transparent plasma, combining particle-in-cell simulations with a theoretical model to understand ion wave breaking and trapping thresholds.

Contribution

It introduces a new theoretical model based on ion wave breaking to describe ion trapping and acceleration in relativistically transparent plasma, validated by simulations.

Findings

Identified the threshold for ion trapping.

Derived analytical scalings for ion and electric field distributions.

Confirmed the model's predictions with simulation results.

Abstract

Self-trapping and acceleration of ions in laser-driven relativistically transparent plasma are investigated with the help of particle-in-cell simulations. A theoretical model based on ion wave breaking is established in describing ion evolution and ion trapping. The threshold for ion trapping is identified. Near the threshold ion trapping is self-regulating and stops when the number of trapped ions is large enough. The model is applied to ion trapping in three-dimensional geometry. Longitudinal distributions of ions and the electric field near the wave breaking point are derived analytically in terms of power-law scalings. The areal density of trapped charge is obtained as a function of the strength of ion wave breaking, which scales with target density for fixed laser intensity. The results of the model are confirmed by the simulations.