Three-dimensional Helical-rotating Plasma Structures in Beam-generated Partially Magnetized Plasmas

Abstract

Azimuthal structures emerging in beam-generated partially magnetized plasmas are investigated using three-dimensional particle-in-cell/Monte Carlo collision simulations. Two distinct instability regimes are identified at low pressures. When the gas pressure is sufficiently high, quasi-neutrality is attained and 2D spiral-arm structures form as a result of the development of a lower-hybrid instability, resulting in enhanced cross-field transport. At lower pressures, quasi-neutrality is not achieved and a 3D helical-rotating plasma structure forms due to development of the diocotron instability. Analytical formulas are proposed for the critical threshold pressure between these regimes and for the rotation frequency of the helical structures. Preliminary experimental verification is provided.

References in corpus (10)

• Simulation benchmarks for low-pressure plasmas: capacitive discharges
• Scaling of Spoke Rotation Frequency within a Penning Discharge
• Numerical analysis of azimuthal rotating spokes in a crossed-field discharge plasma
• Particle-in-cell simulations of anomalous transport in a Penning discharge
• Boundary-induced effect on the spoke-like activity in ExB plasma
• Direct evidence of the gradient drift instability being the origin of a rotating spoke in a crossed field plasma
• Direct Observation of a Cross-Field Current-Carrying Plasma Rotating Around an Unstable Magnetized Plasma Column
• Azimuthal structures and turbulent transport in Penning discharge
• Instability-enhanced transport in low temperature magnetized plasma
• Centrifugal instability in the regime of fast rotation