Sheath and boundary conditions for plasma simulations of a Hall thruster discharge with magnetic lenses

The effect of magnetic lens configuration on sheath in a Hall thruster discharge channels is considered. A model of the plasma-wall transition is developed in the case of large magnetic field incidence angle with respect to the wall. Peculiarity of such case consists in that the potential drop across the magnetic field is set externally. In this case, standard boundary conditions at the sheath edge for plasma simulations fail and a new formulation for those boundary conditions is proposed. The results obtained demonstrate importance of the effect of the magnetic field incidence angle on the sheath boundary conditions for plasma simulations as well as on the energy balance in the Hall thruster discharge.