Numerical study of plasma–wall transition in an oblique magnetic field

A review of the theoretical and computational aspects of plasma–wall transition is presented, starting from the early contributions of Langmuir and Bohm. The conditions for the existence of plasma sheaths in front of a solid surface are established. Various regimes are analyzed — collisionless and collisional, fluid and kinetic, with and without ionization. The partition of the plasma–wall transition into distinct regions (Debye sheath, quasineutral presheath, magnetic presheath, etc.) is also discussed. A recently developed kinetic model is investigated in detail, both analytically and numerically, as a typical example of plasma–wall transition that is also relevant to magnetically confined plasmas encountered in thermonuclear fusion research. Applications to the theory of electrostatic probes are also highlighted.