Inefficient Magnetic-Field Amplification in Supersonic Laser-Plasma Turbulence
A. F. A. Bott, L. Chen, G. Boutoux, T. Caillaud, Alain Duval, M. Koenig, B. Khiar, I. Lantuéjoul, L. Le Déroff, Brian Reville, R. Rosch, Dongsu Ryu, C. Spindloe, B. Vauzour, B. Villette, A. A. Schekochihin, D. Q. Lamb, P. Tzeferacos, Giuliano Gregori, A. Casner
Abstract
We report a laser-plasma experiment that was carried out at the LMJ-PETAL facility and realized the first magnetized, turbulent, supersonic (Ma_{turb}≈2.5) plasma with a large magnetic Reynolds number (Rm≈45) in the laboratory. Initial seed magnetic fields were amplified, but only moderately so, and did not become dynamically significant. A notable absence of magnetic energy at scales smaller than the outer scale of the turbulent cascade was also observed. Our results support the notion that moderately supersonic, low-magnetic-Prandtl-number plasma turbulence is inefficient at amplifying magnetic fields compared to its subsonic, incompressible counterpart.