Model of radial plasma-wall interactions in a Hall thruster

Recent achievements on a sheath/presheath/sheath model of the radial interaction of the plasma discharge with the dielectric walls of a Hall thruster are presented. Trapping and thermalization of the secondary electron emission (SEE) depend on the plasma collisionality. The main new contribution is the sheath structure for partial and zero trapping of the SEE. The SEE yield necessary for charge saturation of the sheath increases as collisionality decreases, and the charge-saturation limit is beyond reach for low collisionality and real materials. Other contributions are the analysis of the ion temperature and of asymmetric profiles in non-planar channel geometries. © 2002 by the authors