Resonant island divertor experiments on TEXT

The first experimental tests of the resonant island divertor (RID) concept have been carried out on the Texas Experimental Tokamak (TEXT). Modular perturbation coils produce static resonant magnetic fields at the tokamak boundary. The resulting magnetic islands are used to guide heat and particle fluxes around a small scoop limiter head. An enhancement in the limiter collection efficiency over the non-island operation, as evidenced by enhanced neutral density within the limiter head, of up to a factor of four is obtained. This enhancement is larger than one would expect given the measured magnitude of the cross-field particle transport in TEXT. It is assumed that electrostatic perturbations occur which enhance the ion convection rate around the islands. Preliminary experiments utilizing electron cyclotron heating (ECH) in conjunction with RID operation have also been performed. (author). 6 refs, 3 figs