Scaling of Small-scale Dynamo Properties in the Rayleigh Taylor Instability and Stably Stratified Turbulence

Fluid instabilities in astrophysical plasmas are ubiquitous and understanding their efficacy for triggering the dynamo process is essential for understanding the origin of magnetic fields in space and astrophysical plasmas. The first part of this poster proposes simple, theoretical scalings of small-scale dynamo properties for the Rayleigh-Taylor instability and tests the predictions with direct numerical simulations. The scaling relations allow a quantitative prediction of the net magnetic amplification and time dependence of the dynamo growth rate. The second half of the poster focuses on small-scale dynamo in stably-stratified turbulence. Stratified turbulence in stellar radiative zones driven by shear instabilities or breaking internal waves should conceivably drive small-scale dynamo action due to the high conductivity of stellar plasma. This mechanism could provide a source of magnetization in more massive stars with extended radiative zones. We present investigations into three principle properties of the small-scale dynamo in stably stratified turbulence–the onset criterion, the growth rate, and the nature of the magnetic field anisotropy. Using our Sun as a representative star, we find that the stratification is strong enough to make the small-scale dynamo active in the solar tachocline for thermal Prandtl number Pr=1.