The effect of magnetic field geometry on viscous damping of rotation in stellarators
The viscous damping of poloidal and toroidal plasma rotation depends on 2 factors, one is collision time times plasma pressure and the other is a geometrical factor C(p), C(t) and C(b). With respect to the geometrical factor significant differences among the various stellarators exist. C(p) is the relevant geometrical factor of poloidal rotation. In axisymmetric devices only the toroidal curvature effect gives rise to magnetic pumping and a finite coefficient C(p). In stellarators, however, additional helical harmonics lead to increased poloidal viscous damping. Reducing the poloidal variation of B, as has been done in optimized configurations of the Helias type, also reduces the poloidal viscous damping. In the neighbourhood of magnetic islands enhanced viscous damping arises due to the distortion of magnetic surfaces.
Bibliographic Reference: Report: IPP 2/334 EN (1996) 25pp.
Availability: Available from the Max-Planck-Institut für Plasmaphysik, 85748 Garching bei München (DE)
Record Number: 199710187 / Last updated on: 1997-04-01
Original language: en
Available languages: en