Magnetized Ablative Rayleigh-Taylor Instability in 3-D

TL;DR

This paper presents the first 3-D extended-MHD simulations of the magnetized ablative Rayleigh-Taylor instability, revealing complex magnetic effects on perturbation growth and stabilization not captured in previous 2-D studies.

Contribution

It provides novel 3-D simulation results showing the influence of magnetic fields on Rayleigh-Taylor instability, challenging prior 2-D assumptions and highlighting the roles of magnetic tension and resistive diffusion.

Findings

Magnetic fields >5T significantly stabilize perturbations along the field.

Magnetic tension does not directly stabilize perpendicular modes but can slow growth.

Resistive diffusion reduces the effectiveness of magnetic tension stabilization.

Abstract

3-D extended-MHD simulations of the magnetized ablative Rayleigh-Taylor instability are presented for the first time. Previous 2-D simulations claiming perturbation suppression by magnetic tension are shown to be misleading, as they do not include the most unstable dimension. For perturbation modes along the applied field direction, the magnetic field simultaneously reduces ablative stabilization and adds magnetic tension stabilization; the stabilizing term is found to dominate for applied fields >5T, with both effects increasing in importance at short wavelengths. For modes perpendicular to the applied field, magnetic tension does not directly stabilize the perturbation, but can result in moderately slower growth due to the perturbation appearing 2-D (albeit in a different orientation to 2-D ICF simulations). In cases where thermal ablative stabilization is dominant the applied field increases the peak bubble-spike height. Resistive diffusion is shown to be important for short wavelengths and long timescales, reducing the effectiveness of tension stabilization.