Study of stationary plasma thrusters using two-dimensional fully kinetic simulations

Abstract

Stationary plasma thrusters are devices that use crossed electric and magnetic fields to accelerate ions to high velocities. Ions are created by collisional ionization of a propellant gas with electrons injected from a hollow cathode external to the thruster. A major issue is the electron transport through the magnetic field. It is known to exceed considerably the values predicted by the classical theory. Various 2D models have shown that wall collisions, which have often been invoked as the origin of this anomalous transport, are in fact insufficient. Anomalous turbulent transport has to be added to the model to recover an adequate conductivity. In the present paper the first 2D kinetic model that shows that, indeed, plasma turbulence can explain the observed conductivity is presented. Without any free parameter the model is able to reproduce numerous experimental features. At the end of the paper a preliminary theoretical analysis of the observed instability is provided.

Analysis of Electron and Microwave Behavior in Microwave Discharge Neutralizer

“…Consequently, we must simulate the sheath at the boundary of the conductor and magnet. We introduce the sheath model 11) as follows. For electrons reaching the boundary, 1) an electron with an energy of less than 20 eV is reflected at the surface boundary, and 2) an electron with an energy larger than 20 eV is removed from the calculation region.…”

Kinetic particle simulation of discharge and wall erosion of a Hall thruster

“…This method was first applied to Hall thruster simulation by Adam and produced promising results, 20 though the wall sheath area was not treated his work. Thus, in this study, the model was improved in the way that the dielectric wall and the wall sheath area were included into the calculation domain for the wall erosion modeling.…”

“…In fact, the previous fully kinetic studies using only true physical properties spent months for the simulation over the characteristic time of the Hall thruster discharge ($100 ls). 20,21 Consequently, this major drawback of PIC-DSMC model makes it difficult to conduct parametric study or the wall geometry time-evolution modeling, and there was no successful Hall thruster lifetime simulation conducted so far to be best of our knowledge. Naturally, notable techniques for speeding up the computation were developed and investigated.…”

“…The fully Kinetic PIC Direct Simulation Monte Carlo (DSMC) model 14 tracing the trajectory of all kinds of particles was first applied to Hall thrusters by Hirakawa 15 and was further developed and improved. [16][17][18][19][20][21] It is well known that the space and time resolution are, respectively, restricted by the Debye length and the plasma frequency in fully kinetic PIC DSMC models, which makes the simulation extremely computationally expensive. In fact, the previous fully kinetic studies using only true physical properties spent months for the simulation over the characteristic time of the Hall thruster discharge ($100 ls).…”

Characterization of Fluctuations and Electron Transport in Two-Dimensional Simulations of Hall Thrusters using an Axial-Azimuthal Hybrid Model

“…(This contrasts with some kinetic simulations where only an angular sector is resolved.) 10 In the axial direction, the peaked magnetic field around the channel exit imposes an inhomogeneity in the device. As a result, we employ a non-uniform grid in the axial coordinate of 40 grid points (the grid clusters its points around the peak in the magnetic field, the region where the gradients are expected to be largest).…”