STUDY OF LOCAL ELECTRON HEAT-TRANSPORT ON TFTR

The anomously fast relaxation of the perturbations to the electron tem perature profile caused by a sawtooth crash has been studied extensive ly on TFTR. It is shown that on a short time-scale the heat pulse is n ot simply diffusive as has been generally assumed, but that modelling of the heat pulse requires a transient enhancement in chi(e) following the sawtooth crash. It is also shown that the time dependent enhancem ent in chi(e) predicted by non-linear thermal transport models, i.e. i ncremental chi models Dr the Rebut-Lallia-Watkins transport model, is much smaller than that required to explain the anomalies the heat puls e propagation.