Lower Hybrid Drift in Simulations of Hypersonic Plasma

Abstract:

It has been shown experimentally that hypersonic plasma (defined as moving with a bulk flow velocity of more than 5 to 10 times the Mach speed) traveling through a magnetic field will create a diamagnetic cavity, or bubble [1]. At the edge of the bubble, opposing field and density gradients can drive the lower hybrid drift instability [2]. We will explore two and a half dimensional (2 space and 3 velocity dimensions) simulations of hypersonic plasma within a parameter regime motivated by the aforementioned diamagnetic bubble experiments, wherein we find oscillations excited near the lower hybrid frequency propagating perpendicular to the bulk motion of the plasma and the background magnetic field. The simulations are run using the implicit PIC code iPIC3D so that we are able to capture dynamics of the plasma below ion scales, but not be forced to resolve all electron scales [3].

[1] Niemann et al, Phys. Plasmas 20, 012108 (2013)

[2] Davidson et al, Phys. Fluids, Vol. 20, No. 2, February 1977

[3] S. Markidis et al, Math. Comput. Simul. (2009), doi 10.1016/j.matcom.2009.08.038