BOUNDARY-CONDITIONS INCLUDING SHEATH EFFECTS AT A PLASMA-FACING SURFACE

It has recently been reported that space-charge saturation occurs adja cent to almost every commonly used plasma-facing material for plasma t emperatures above similar to 50 eV. An electron emission coefficient, defined as the average number of surface-emitted electrons per inciden t plasma electron, which is near or above unity is responsible for the occurrence of space-charge saturation. With this motivation, a fully kinetic self-consistent theory capable of describing the plasma sheath under conditions of space-charge saturation is developed. The theory is than used to obtain boundary conditions which are suitable for inco rporation into computer programs which simulate plasmas.