Kinetic Theory Analysis of Sheaths and Shocks

The properties of sheaths formed on the divertor plates have a strong influence on plasma behavior in the scrape‐off‐layer. What makes these properties quite different from those of „standard”︁ Debye sheaths is that the magnetic field in the SOL intersects divertor plates at a shallow angle. The survey covers the following issues of the sheath physics in an oblique magnetic field: sheath structure and particle trajectories; effect of diamagnetic and electric drifts on the current‐voltage characteristics of the sheath; effect of the surface „roughness”︁ and „waviness”︁ on sheath properties and plasma transport; possible role of the anomalous transport, etc. The second class of objects briefly discussed in the present survey are shock waves which can appear in the divertor region if the incoming plasma flow is supersonic. The outline of the kinetic theory of impurity retention by the shocks is presented.