DOMINANCE OF CONVECTIVE HEAT-TRANSPORT IN THE CORE OF TFTR (TOKAMAK FUSION TEST REACTOR) SUPERSHOT PLASMAS

Using perturbations in electron density and temperature induced by sma ll helium gas puffs in TFTR (Tokamak Fusion Test Reactor) [Plasma Phys . Controlled Nucl. Fusion Res. 1, 51 (1986)], the dominance of convect ive heat transport in the core (r/a<0.4) of supershot plasmas has been demonstrated in a new way. The TRANSP [J. Comput. Phys. 43, 61 (1981) ] transport code was used to calculate the time-dependent particle and heat fluxes. Perturbations in the calculated convective and total ele ctron heat fluxes were compared. They demonstrate that the conductive component decreases moving into the supershot core, and the convective component dominates in the supershot core. These results suggest a di fferent transport drive in the supershot core compared to that in the rest of the supershot plasma.