Non-Linear Ablative Rayleigh-Taylor Instability: Increased Growth due to Self-Generated Magnetic Fields

TL;DR

This paper investigates how self-generated magnetic fields, via the Biermann battery mechanism, enhance the growth of the non-linear ablative Rayleigh-Taylor instability, with simulations validating the proposed scaling laws.

Contribution

It introduces a scaling law for magnetic field effects on RT instability growth, validated through extended-magnetohydrodynamic simulations, highlighting the role of magnetic fields in inertial confinement fusion.

Findings

Magnetic flux generation scales with spike height.

Short wavelength spikes have strongly enhanced electron magnetization.

Magnetic fields influence spike growth through thermal conduction suppression and heat-flow deflection.

Abstract

The growth rate of the non-linear ablative Rayleigh-Taylor (RT) instability is enhanced by magnetic fields self-generated by the Biermann battery mechanism; a scaling for this effect with perturbation height and wavelength is proposed and validated with extended-magnetohydrodynamic simulations. The magnetic flux generation rate around a single RT spike is found to scale with the spike height. The Hall Parameter, which quantifies electron magnetization, is found to be strongly enhanced for short wavelength spikes due to Nernst compression of the magnetic field at the spike tip. The impact of the magnetic field on spike growth is through both the suppressed thermal conduction into the unstable spike and the Righi-Leduc heat-flow deflecting heat from the spike tip to the base. Righi-Leduc is found to be the dominant effect for small Hall Parameters, while suppressed thermal conduction dominates for large Hall Parameters. These results demonstrate the importance of considering magnetic fields in all perturbed inertial confinement fusion hot-spots.