Improvement of radial confinement of plasma via applying rotating magnetic fields

Abstract

We report a novel method to control the plasma radial transport, namely, applying a rotating magnetic field (RMF) to create azimuthal shear flow, which is found to change the transport from Bohm to classical diffusion if the ratio of magnetization parameter to penetration parameter is greater than 1.5. Upon application of the RMF, the peak density is observed to increase by 33% above the normal value. Specifically, the ratio increases from 4 × 1018 m−3 to 6 × 1018 m−3, and the corresponding density gradient length changes from 11 cm to 6 cm, or the steepness increases by about a factor of 2. Further increasing the RMF strength cannot steepen the density further. The results suggest the RMF can be a non-intrusive method to control the radial transport and hence the plasma density profile.