Boundary conditions in the source of an electron beam on the surface of the anode plasma with a supersonic ion flow

A solution for the one-dimensional Poisson problem for a layer on the surface of a plasma ion emitter is obtained. The case of plasma with a directed ion velocity greater than the ionic sound one is considered. Moreover, the plasma surface is irradiated with an electron beam. As applied to the parameters of deuterium plasma flowing out of a gas dynamic open magnetic trap GDT, a physical model of a layer with boundary conditions on the plasma surface is formulated. It allows a two-dimensional numerical simulation of the source of an electron beam injected into a trap.