Estimation of electron mobility in the hollow cathode plume of a Hall effect thruster with different electrical configurations

In the paper, we assess the effects of electrical configuration on the plasma properties in the near-field hollow cathode discharge that is center mounted on a Hall effect thruster. The axial profile of the electron density and temperature is obtained using incoherent laser Thomson scattering for three electrical configurations of the thruster body, i.e., grounded, floating, and cathode-tied. The effective electron mobility is estimated using a one-dimensional plasma fluid model with the measurement data as an input to the model. The estimation using the data-driven framework reveals that the electron conductivity is the highest when the thruster body is electrically grounded while the electron conductivity is comparable between the floating and cathode-tied configurations, indicating that the current path and electron dynamics of the hollow cathode discharge are affected by the electrical configurations.