Characteristics of microwave ECR ion thruster powered with plate antenna in cross-magnetic field: Standing wave, skin effect, and mode transition
S. H. Fu, Zhenfeng Ding
Abstract
In a 2.45 GHz electron cyclotron resonance xenon ion source powered with circular plate-antenna, a rapid evolution of radial plasma-profile with discharge power in a region below 35 W and the abrupt jump of ion beam current accompanied by sudden radial-expansion of discharge glow were observed. Based on analyses about quantified glow images captured from the end-view of the discharge chamber and the ion beam current against the discharge power, the fast evolution of the radial plasma-profile is attributed to the counteraction of standing wave and the skin effect, the coincidence of enhanced microwave absorption in the electron plasma resonance layer, and the transverse magnetic confinement of electrons. The jump of ion beam current and the sudden radial-expansion of discharge glow are confirmed to be originated from the extraordinary-wave discharge at the electron cyclotron resonance layer beyond the plate antenna when the skin effect is dominant.