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

Experiments performed with the OMEGA EP laser are used to measure Biermann battery magnetic field generation driven by high power laser-solid interactions. Proton deflectometry observes changes to the strength, spatial profile, and temporal dynamics of the self-generated magnetic fields. By varying the target material or laser intensity, measurements of the magnetic flux during the interaction are used to help validate extended magnetohydrodynamic (MHD) simulations using the code GORGON. Comparison of the experimental and simulation results suggest that kinetic effects cause suppression of the Biermann battery mechanism in laser-plasma interactions. Counter to a standard MHD understanding, the experiments generated more magnetic flux as the target atomic number is increased. These results are relevant to both direct and indirect-drive inertial confinement fusion.