Local Tests of Parallel Electrical Resistivity in the Tokamak Fusion Test Reactor
Authors: S.H. Batha, F.M. Levinton, A.T. Ramsey, G.L. Schmidt, and M.C. Zarnstorff
The motional Stark effect (MSE) polarimeter measures the local magnetic field pitch angle, proportional to the ratio of the poloidal to toroidal magnetic fields, in the Tokamak Fusion Test Reactor (TFTR). We have used the polarimeter to measure the temporal evolution of the local value of the magnetic field pitch angle during large changes in the current profile, such as during a current ramp or discharge initiation. The measured evolution is compared to the evolution predicted by classical and neoclassical resistivity models. The neoclassical resistivity model is a better predictor of the local pitch angle temporal evolution than the classical model.