Hall Effect Thruster with an ALN chamber

The potential of AlN as a material for Hall thruster channels is assessed on the basis of actual thruster performances, computer simulations of the discharge and microscopy studies of an eroded channel. Comparison of experimental and numerical data provides further evidence that secondary electron emission (SEE) is the main phenomena responsible for wall-induced currents. The high discharge currents observed are characteristic for high SEE materials and result in a much lower thruster efficiency than with a conventional BN-SiO2 channel. The delivered thrust is also affected in the medium voltage range. With respect to erosion, scanning electron images performed after 14 hours of operation already reveal precursors of anomalous erosion patterns on the channel front side.