Magnetic fields and heat flow are strongly coupled in plasmas but while it is well known that magnetisation can suppress heat flow, the changes in the magnetic field are more poorly understood. I describe experiments studying the generation and advection of magnetic fields on the nanosecond timescale in a laser-heated gas jet.

In the first experiment, we directly measured cavitation of an applied magnetic field inside a plasma driven by the Nernst effect, in which heat flow causes expulsion of the field from the hottest regions of the plasma. We demonstrate that the field is advected by heat flow in advance of the plasma expansion, potentially disrupting magnetised inertial confinement fusion schemes.

In a second experiment, we used a controlled density gradient to generate a magnetic field through the Biermann battery. We study how a flux limiter, introduced to bring the heat transport in line with experimental observations, can actually lead to unphysically high predictions for the thermo-electric and magnetic fields. In both situations we explore the role of kinetic effects, and aim to show the regimes where fluid models work well or poorly.