Ballistic contributions to heat-pulse propagation in the TFTR tokamak

Abstract

Measurements on the TFTR tokamak of the electron-temperature-profile evolution and soft-x-ray emissivity on a fast (10-\ensuremath{\mu}sec) time scale during a sawtooth crash show that significant heat is deposited beyond the mixing (or reconnection) radius within 200 \ensuremath{\mu}sec following a sawtooth crash. This extended region in which electron heat is redistributed during the sawtooth crash substantially complicates the determination of heat transport properties from the subsequent heat pulse propagation. It is shown that the relaxation of this extended perturbation is consistent with the power-balance estimates of the local thermal diffusivity.