An unexamined collision-less mechanism for electron mobility in Hall thrusters

This paper presents the observation of an electron mobility mechanism in Hall thruster fields that cannot be described using the theories of classical mobility or Bohm mobility, where this mobility was observed in the Hall Electron Mobility Gage, a device dedicated to investigating electron mobility. The mechanisms most commonly cited for enhanced electron mobility in Hall thrusters-collisions with dielectric walls and self-sustained plasma oscillations-have been removed, yet the mobility observed in this device fails to exhibit a magnitude agreeing with the classical prediction. The magnitude of the experimental mobility falls between the predictions of classical and Bohm mobility (Bohm coefficient of 1/16) and exhibits behavior that suggests the presence of both a collisional and collisionless mechanism for mobility. This collisionless mechanism has not yet been identified