Observation of Nonclassical Radial Current Diffusion in a Fully Bootstrap Current Driven Tokamak

Abstract

Reconstruction and modeling of the plasma current profiles in a fully pressure driven tokamak have been performed in the Current Drive Experiment-Upgrade. The reconstructed experimental current profile has a significant deviation from that of the calculated neoclassical currents. Satisfactory agreement between the measured and calculated model profiles was obtained by including a helicity conserving current diffusion term in the modeling which created the required self-generated ''seed'' current.