Evidence from injection into the TCV device of laser ablated, non-recycling silicon impurities shows that the transport of impurities confinement can be remarkably different from that of energy. The ratio of impurity to energy confinement times ranges from near unity in Ohmic discharges to 5 in the presence of high power ECCD. In Ohmic discharges in deuterium, above a threshold of density and of safety factor near q95 = 4.5, the impurity confinement time increases abruptly by a factor of 2 and is sometimes accompanied by indefinite retention of non-recycling impurities within the sawtooth mixing radius.
ASJC Scopus subject areas
- Nuclear Energy and Engineering
- Condensed Matter Physics