A non-neutral 1D fluid model of Hall thruster discharges: full electroninertia and anode sheath reversal

Abstract A non-neutral model of the axial plasma discharge in a Hall thruster, including full electron inertia, is presented. In the finite-volume formulation, two types of sheath boundary conditions previously used in the literature are tested and proven to behave practically identically in this model. 
Both normal and reversed (i.e. electron repelling and attracting, respectively) anode sheaths are admitted. 
This model is compared with the quasineutral model developed in a previous work, which includes only azimuthal electron inertia and normal anode sheaths. Both models agree excellently within the parametric region where steady-state solutions with a normal anode sheath exist.
The non-neutral model shows the absence of steady-state solutions with a reversed anode sheath. Nonetheless, a reversed sheath can appear during the transient to a steady-state solution with a normal sheath and the periodic transition from a normal to a reversed sheath can be observed in the presence of breathing-mode oscillations.
 In other cases, the reversed sheath leads to the discharge shut-off. Full electron inertia is always important in presence of a reversed sheath. The parametric threshold from a stationary solution to a breathing mode one differs somehow between the non-neutral and the quasi-neutral model.