Ion Velocity Measurements in a Linear Hall Thruster

This work presents the general operation and the near exit plane velocity field of the Stanford Linear Hall thruster in a high vacuum environment. The ionized propellant velocities were measured using laser induced fluorescence of the excited state xenon ionic transition at 834.7 nm. Ion velocities were interrogated from the channel exit plane to a distance 30 mm from it. Both axial and transverse (along the electron Hall current direction) velocities were measured. These results presented here, combined with those of previous works, highlight the high sensitivity of electron mobility inside and outside the channel, depending on the background gas density, type of wall material, or magnetic field intensity. When operated with a low background pressure, the particular Hall discharge studied here creates an ion accelerating electrostatic field mainly outside of the channel, in a narrow zone located 5-20 mm away from the exit plane.