Observation of non-classical radial current diffusion in a fully bootstrap current driven tokamak

摘要

Reconstruction and modeling of the plasma current profiles in a fully pressure-driven tokamak have been performed in the Current Drive Experiment-Upgrade (CDX-U). 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.