Measurement of magnetic cavitation driven by heat flow in a plasma

TL;DR

This study directly measures how heat flow in a plasma expels magnetic fields, revealing rapid magnetic field advection that impacts high energy density plasma dynamics and fusion schemes.

Contribution

It provides the first direct measurement of magnetic field expulsion driven by heat flow in plasma using proton radiography.

Findings

Magnetic fields are advected by heat flow within nanoseconds.

Heat-driven magnetic field expulsion affects plasma dynamics.

Implications for magnetized inertial confinement fusion schemes.

Abstract

We describe the direct measurement of the expulsion of a magnetic field from a plasma driven by heat flow. Using a laser to heat a column of gas within an applied magnetic field, we isolate Nernst advection and show how it changes the field over a nanosecond timescale. Reconstruction of the magnetic field map from proton radiographs demonstrates that the field is advected by heat flow in advance of the plasma expansion. This changes the dynamics of high energy density plasmas, in which heat flows and fields are strongly coupled, and may disrupt magnetised inertial confinement fusion schemes.