Enhanced transport of impurity ions and electron heat in tore supra ohmic discharges following nickel laser blow-off injection

摘要

Nickel has been injected into ohmic Tore Supra(TS)discharges with and without activation of the ergodic divertor(ED). The nickel ion transport is studied by means of an impurity transport code, and the radial profiles of the diffusion coefficient D and of the inward convection velocity V are obtained by simulating the soft X ray brightness and emissivity time evolutions. The simulations confirm two previously reported conclusions: the presence of a central with reduced transport coefficients and, with the ED activated, the necessity of introducing a peripheral transport barrier(with increased inward convection and/or reduced diffusion).