Non-classical plasma sheaths: Space-charge-limited and inverse regimes under strong emission from surfaces

Hybrid models feature a kinetic treatment of the ion species (and in some cases of the neutrals as well) so that CEX collisions are correctly captured, and a fluid modeling of the fastest species, the electrons.

“In fact, they feature a kinetic treatment of the ion species (and in some cases of the neutrals as well) so that CEX collisions are correctly captured, and a fluid modeling of the fastest species, the electrons, which are subject to conservation equations.”

Hybrid models represent the best compromise in terms of accuracy and computational cost for modeling plasma thruster plume expansion and its interaction with the spacecraft.

“Hybrid models 225-234 have therefore emerged in this context, as they represent the best compromise in terms of accuracy and computational cost for modeling the plasma thruster plume expansion and its interaction with the spacecraft.”

The inclusion of non-neutral regions close to the spacecraft in a hybrid model assuming polytropic electrons and charge non-neutrality has the effect of increasing the ion back flow current by approximately 20%.

“The simulation results from a hybrid model assuming polytropic electrons and charge non-neutrality are shown in Fig. 9, where the inclusion of non-neutral regions close to the spacecraft is clearly visible (the potential adapts to the satellite ground potential) and has the effect of increasing the ion back flow current by approx. 20%.”