Nonlinear turbulence theory for Buneman instability

The electrostatic Buneman instability may be a source anomalous resistivity which may be important for a number of space physical applications. This talk discusses a weak turbulence theory for reactive Buneman instability, and comparison against numerical simulation is also made. The self-consistent theory involves quasi-linear velocity space diffusion equation for the particles and nonlinear wave kinetic equation that includes quasi-linear (or induced emission) term as well as nonlinear wave-particle interaction term (or a term that represents an induced scattering off ions). The simulation of Buneman instability involves one-dimensional electrostatic Vlasov simulation technique. Under the assumption of self-similar drifting Gaussian distribution function for the electrons, it is shown that the current reduction and the accompanying electron heating as well as electric field turbulence generation can be discussed in a self-consistent manner. Upon comparison with the Vlasov simulation result it is found that quasi-linear wave kinetic equation alone is insufficient to account for the final saturation amplitude. Upon including the nonlinear scattering term in the wave kinetic equation, however, it is found that a qualitative agreement with the simulation is recovered.