Laboratory Evidence of Fluctuation Dynamo in Supersonic Turbulence*

Highly compressible magnetized turbulence is prevalent in the interstellar and intergalactic mediums. Stochastic fluctuations in turbulent, supersonic plasmas have a marked effect on the magnitude of the magnetic fields that permeate them, namely, dynamo action. Tapping into the plasma kinetic energy reservoir, turbulent motions cause a sequence of transformations in the magnetic fields that results in the amplification of the magnetic energy density. While fluctuation dynamo is commonplace in astrophysical systems, it is hard to realize in terrestrial laboratories. Here we demonstrate, using laser-driven experiments at the Omega Laser Facility, that supersonic turbulence is indeed capable of fluctuation dynamo action. The experiments exploit the TDYNO experimental platform, which demonstrated turbulent dynamo in the laboratory for the first time [Tzeferacos et al. Nat. Comm. 9, 591, 2018], meticulously characterized it [Bott et al. PNAS 118, e2015729118, 2021] in the subsonic regime, and was extended to study supersonic turbulence [Bott et al. Phys. Rev. Lett. 127, 175002, 2021]. We detail the experiments that led to this demonstration, as well as the FLASH simulation campaigns that we executed for the design and interpretation of the experiments.