The Effect of Self-Generated Magnetic Fields on Ablative Rayleigh--Taylor Instability Dynamics

Measurements of magnetic (B) field induced by the ablative Rayleigh--Taylor instability (ARTI) in laser-produced plasmas\footnote{ M. J.-E. Manuel \textit{et al.}, Phys. Rev. Lett. \textbf{108}, 255006 (2012).} indicate that it may play an important role in the dynamics of this instability. The B field modifies the thermal conduction, and the Righi--Leduc term can be destabilizing by moving heat away from the top of the spike toward the bubbles.$^{\mathrm{\thinspace }}$\footnote{ A. Nishiguchi, Jpn. J. Appl. Phys. \textbf{41}, 326 (2002).}$^{\mathrm{,}}$\footnote{ C. A. Walsh \textit{et al.}, Phys. Rev. Lett. \textbf{118}, 155001 (2017).} In this talk, we present an analysis of the linear stage of the ARTI with self-generated B fields. We identify an unstable mechanism arising from the interplay between the Biermann battery term that generates B field, which in turn affects the energy equation through the Righi--Leduc term. In essence, this mechanism is similar to the magnetothermal instability arising in the underdense corona.\footnote{ D. A. Tidman and R. A. Shanny, Phys. Fluids \textbf{17}, 1207 (1974).} At the ablation front, however, the coupling of this mechanism with the hydrodynamics needs to be self-consistently solved. We~discuss the new dispersion relation derived.