Spontaneous magnetization of collisionless plasma through the action of a shear flow

• DOI: 10.48550/arxiv.2110.01134
• Publication Date: 2021-01-01
• Authors: Muni Zhou; Vladimir Zhdankin; Matthew W. Kunz; Nuno Loureiro; Dmitri Uzdensky
• Keywords: Weibel instability

We study in a fully kinetic framework the generation of seed magnetic fields through Weibel instability driven an initially unmagnetized plasma by large-scale shear force. develop analytical model that describes development thermal pressure anisotropy via phase mixing, ensuing exponential growth linear stage, and its saturation when become strong enough to instigate gyromotion particles thereby inhibit their free-streaming. The predicted scaling dependencies saturated on key parameters (e.g., ratio system scale electron skin depth, forcing amplitude) are confirmed 3D 2D particle-in-cell simulations using electron-positron plasma. This work demonstrates spontaneous magnetization collisionless motions as simple flow, therefore has important implications for magnetogenesis dilute astrophysical systems.