Magnetogenesis in a Collisionless Plasma: From Weibel Instability to Turbulent Dynamo

• DOI: 10.3847/1538-4357/ad0b0f
• Publication Date: 2023-12-19T14:38:13Z
• Authors: Muni Zhou; Vladimir Zhdankin; Matthew W. Kunz; Nuno F. Loureiro; Dmitri A. Uzdensky
• Keywords: Weibel instability; Equipartition theorem; Intracluster medium; Gyroradius

Abstract We report on a first-principles numerical and theoretical study of plasma dynamo in fully kinetic framework. By applying an external mechanical force to initially unmagnetized plasma, we develop self-consistent treatment the generation “seed” magnetic fields, formation turbulence, inductive amplification fields by fluctuation dynamo. Driven large-scale motions unmagnetized, weakly collisional are subject strong phase mixing, which leads development thermal pressure anisotropy. This anisotropy triggers Weibel instability, produces filamentary plasma-kinetic scales. The is thereby magnetized, enabling efficient stretching folding Larmor-scale instabilities such as firehose mirror. scattering particles off associated microscale fluctuations provides effective viscosity, regulating field morphology turbulence. During this process, seed further amplified until energy equipartition with turbulent flow reached. demonstrating that can be generated from through flows, work has important implications for origin intracluster intergalactic mediums.