Large-scale azimuthal structures in Hall-type plasma discharges

An explanation of large-scale low-frequency oscillations observed by means of a high-speed camera in different Hall-type plasma devices (magnetrons, Penning discharges, Hall thrusters, etc.) is proposed. They can be interpreted as the beating between high-frequency eigenmodes of gradient drift instability occurring in spatially bounded nonuniform plasmas. The resemblance of the experimental data obtained with the finite exposure time and the calculated characteristics of high-frequency modes beating is highlighted. The main results are obtained analytically in a magnetron-like configuration with the axial magnetic field and the radial electric field. © 2019 Author(s).