Ion acoustic turbulence in the hollow cathode plume of a hall effect thruster
The ion acoustic turbulence in the plume of a hollow cathode operating in a Hall effect thruster is experimentally and analytically characterized. A recent theoretical study suggests that the increased resistivity as a result of the acoustic waves may dictate the cathode coupling voltage. The growth and strength of these waves are susceptible to changes in the neutral density or facility background pressure. A Langmuir probe is used to measure the steady state plasma parameters and wave properties with varying cathode how fraction and background pressure. Results show that with increasing cathode now fraction, the cathode coupling voltage decreases. Additionally, with increasing now fraction, the electron temperature decreases. Both of these are consistent with lower ion acoustic turbulence strength. Ion saturation probes measure the wave properties. Results shows that the anomalous collision frequency grows with respect to the classical collision frequency with decreasing cathode now fraction. This suggests that ion acoustic turbulence strength is correlated with the cathode coupling voltage in a Hall thruster for varying neutral density.
