Buneman instability in a magnetized current-carrying plasma with velocity shear

Abstract

Buneman instability is often driven in magnetic reconnection. Understanding how velocity shear in the beams driving the Buneman instability affects the growth and saturation of waves is relevant to turbulence, heating, and diffusion in magnetic reconnection. Using a Mathieu-equation analysis for weak cosine velocity shear together with Vlasov simulations, the effects of shear on the kinetic Buneman instability are studied in a plasma consisting of strongly magnetized electrons and cold unmagnetized ions. In the linearly unstable phase, shear enhances the coupling between oblique waves and the sheared electron beam, resulting in a wider range of unstable eigenmodes with common lower growth rates. The wave couplings generate new features of the electric fields in space, which can persist into the nonlinear phase when electron holes form. Lower hybrid instabilities simultaneously occur at $k_{\parallel }/k_{\perp }\sim \sqrt{m_e/m_i}$ with a much lower growth rate, and are not affected by the velocity shear.

Accepted by Physics of Plasma

References in corpus (2)

• Electron Holes and Heating in the Reconnection Dissipation Region
• Nonlinear Development of Streaming Instabilities In Strongly Magnetized Plasmas

Cited by in corpus (4)

• Electron acceleration and thermalization at magnetotail separatrices
• Kinetic turbulence in fast 3D collisionless guide-field magnetic reconnection
• A Brief Review on Particle Acceleration in Multi-island Magnetic Reconnection
• Two-Fluid Description of Wave-Particle Interactions in Strong Buneman Turbulence