2D3V Particle-in-cell simulations of Electron Cyclotron Drift Instability and anomalous electron transport in ExB plasmas
This thesis is devoted to nonlinear physics of plasmas investigated with kinetic modeling. The emphasis is on the characterization of waves, instabilities, and anomalous electron transport. The main topic is related to partially magnetized plasmas immersed in crossed ExB fields with magnetized electrons and unmagnetized ions. Such plasmas are abundant in many applications such as Hall thrusters devices for space propulsion and material processing. The nonlinear evolution of the Electron Cyclotron Drift Instability (ECDI) driven by the electron ExB drift in partially magnetized plasmas and anomalous electron transport in two dimensions are studied using particle-in-cell (PIC) simulations. PIC simulations were performed for the parameters typical of the Hall-effect thruster in two-dimensional azimuthal-radial geometry to investigate the role of the boundaries conditions, electric and magnetic field magnitudes, sheath losses and finite-length on the mode development and anomalous electron current. The turbulence and the induced anomalous electron current are studied. Nature of the anomalous current and contribution of different wavelength are investigated. It is shown that the magnitude of the anomalous current can be explained as a ExB drift of magnetized electrons in fluctuating fields. The same PIC code was used for a benchmark project in simulations of a similar radial-azimuthal configuration of a Hall thruster. Seven different groups using independently developed codes were able to capture the same physics, both for ECDI and Modified Two-Stream Instability (MTSI) modes. An additional study related to the role of noise in kinetic plasma simulations is presented. It confirmed that statistical particle noise could distort some Buneman-type instabilities to be identified in the linear regime.
Hall thruster, plasma instabilities, anomalous current, particle-in-cell method
Master of Science (M.Sc.)
Physics and Engineering Physics