Anisotropic heating and magnetic field generation due to Raman scattering in laser-plasma interactions

TL;DR

This paper reveals a new mechanism for magnetic field generation in laser-plasma interactions, where Raman scattering induces electron temperature anisotropy leading to Weibel instability-driven magnetic fields, confirmed by simulations.

Contribution

It introduces a novel process linking Raman scattering to magnetic field generation via electron anisotropy in laser-plasma interactions.

Findings

Magnetic fields grow due to electron temperature anisotropy caused by Raman scattering.

Simulation results confirm the Weibel instability as the magnetic field generation mechanism.

The setup provides a platform to study long-term Weibel instability evolution.

Abstract

We identify a mechanism for magnetic field generation in the interaction of intense electromagnetic waves and underdense plasmas. We show that Raman scattered plasma waves trap and heat the electrons preferentially in their propagation direction, resulting in a temperature anisotropy. In the trail of the laser pulse, we observe magnetic field growth which matches the Weibel mechanism due to the temperature anisotropy. We discuss the role of the initial electron temperature in our results. The predictions are confirmed with multi-dimensional particle-in-cell simulations. We show how this configuration is an experimental platform to study the long-time evolution of the Weibel instability.