Simulating the external magnetic field in short-pulse intense laser-plasma interaction

TL;DR

This paper presents a simple simulation method for external magnetic fields in short-pulse laser-plasma interactions using a virtual current layer, validated through 3D particle-in-cell simulations and analytic modeling.

Contribution

It introduces a novel simulation approach with a virtual current layer to model external magnetic fields in laser-plasma interactions, supported by simulation and analytic results.

Findings

The magnetic field distribution and evolution are successfully simulated.

Magnetization occurs over longer timescales than laser-plasma interaction.

Analytic models predict long-term magnetic diffusion and diamagnetic currents.

Abstract

Imposing an external magnetic field in short-pulse intense laser-plasma interaction is of broad scientific interest in related plasma research areas. We propose a simple method using a virtual current layer by introducing an extra current density term to simulate the external magnetic field, and demonstrate it with three-dimensional particle-in-cell simulations. The field distribution and its evolution in sub-picosecond time scale are obtained. The magnetization process takes a much longer time than that of laser-plasma interaction due to plasma diamagnetism arising from collective response. The long-time evolution of magnetic diffusion and diamagnetic current can be predicted based on a simplified analytic model in combination with simulations.