Measuring magnetic flux suppression in high-power laser-plasma interactions

TL;DR

This study investigates magnetic flux suppression in high-power laser-plasma interactions, using experiments and simulations to understand the Biermann battery mechanism and its dependence on target material and laser intensity.

Contribution

It provides experimental validation of extended MHD simulations and reveals kinetic effects suppressing magnetic flux generation in laser-driven plasmas.

Findings

Kinetic effects suppress Biermann battery magnetic fields.

Magnetic flux increases with higher target atomic number.

Experimental results validate extended MHD simulation predictions.

Abstract

Biermann battery magnetic field generation driven by high power laser-solid interactions is explored in experiments performed with the OMEGA EP laser system. Proton deflectometry captures changes to the strength, spatial profile, and temporal dynamics of the self-generated magnetic fields as the target material or laser intensity is varied. Measurements of the magnetic flux during the interaction are used to help validate extended magnetohydrodynamic (MHD) simulations. Results suggest that kinetic effects cause suppression of the Biermann battery mechanism in laser-plasma interactions relevant to both direct and indirect-drive inertial confinement fusion. Experiments also find that more magnetic flux is generated as the target atomic number is increased, which is counter to a standard MHD understanding.