Kinetic sheath in presence of multiple positive ions, negative ions, and particle wall emission

The region between a Maxwellian plasma source and a floating or current-carrying surface is described by a static, one-dimensional collisionless kinetic sheath model. In the plasma source, electrons, negative ions, and several positive ion species with different temperatures can be included. The surface (wall) can emit electrons and/or negative ions. When the flux of surface-emitted negative ions and/or electrons reaches a critical value, the sheath becomes space-charge saturated, which leads to the formation of a virtual cathode in front of the emitting wall and sets the maximum current density that can be transported from the surface to the plasma. The analytical results are benchmarked against a particle-in-cell code.