Index of content:
Volume 5, Issue 6, June 1998
5(1998); http://dx.doi.org/10.1063/1.872926View Description Hide Description
In this paper a sheath near the wall whose surface is “rough,” containing random bumps with a height comparable to the distance between them is considered. The magnetic field is assumed to form a shallow angle with the wall (as in a tokamakdivertor) and the scale of nonuniformities is assumed greater than the ion gyroradius. The following new effects caused by surface roughness are identified: (1) The fraction of the surface “wetted” by the plasma becomes much smaller than for a flat wall. (2) The ion subsheath is broadened and the diamagnetic current in it acquires a complex three-dimensional structure. (3) Cross-field nonuniformities of the plasma potential appear in the bulk plasma.