Optical emission spectroscopy for very low power hall effect thrusters

Optical measurement technique to characterize the electron temperature in xenon Hall effect thrusters is presented. The technique is demonstrated on two small thrusters: The Narrow Channel Hall Thruster with a channel diameter of 30 mm, and the Outside Electric Field Thruster with a channel diameter of 15 mm. The optical emission spectra were measured along the plume axis and the electron temperature was calculated using two different theoretical models for the plasma. The optical results were compared to electrostatic probe measurements with good agreement between the methods.