Experimental and Theoretical Studies of a Low Power Cylindrical Hall Thruster

摘要

Summary form only given. Hall thruster is a mature electric propulsion device that holds considerable promise in terms of the propellant saving potential. The annular design of the conventional Hall thruster, however, does not naturally lend itself to scaling to low power. The efficiency tends to be lower, and the lifetime issues are more aggravated. Cylindrical geometry Hall thrusters have lower surface-to-volume ratio than conventional annular thrusters and, thus, seem to be more promising for scaling down. A miniaturized cylindrical Hall thruster (2.6 cm channel outer diameter, 50-300 W power range) exhibits performance comparable with conventional annular Hall thrusters of the similar size. The cylindrical thruster has discharge characteristics similar to those of the annular thrusters, but its propellant ionization efficiency is much higher than that of the annular thrusters. Significantly, a large fraction of multicharged xenon ions might be present in the outgoing ion flux generated by the cylindrical thruster. The operation of the cylindrical thruster is quieter than that of the annular thrusters. The characteristic peak in the discharge current fluctuation spectrum at 50-60 kHz appears to be due to ionization instabilities. Electron cross-field transport in a 2.6 cm cylindrical Hall thruster was studied through the analysis of experimental data and Monte Carlo simulations of electron dynamics in the thruster channel. Kinetic modeling of electron and ion dynamics in the thruster channel allows one to optimize the electron confinement and ion acceleration over a family of realizable magnetic field and plasma potential distributions