HEAT AND PARTICLE TRANSPORT IN THE DIVERTOR AND REMOTE RADIATIVE COOLING ON JT-60U

摘要

The behavior of principal divertor plasma parameters such as the ion flux, electron temperature and particle recycling was investigated under the condition of remote radiative cooling in L-mode and ELMy H-mode discharges. The ion flux to the separatrix strike points starts to decrease just before a MARFE onset irrespective of the ion ▽B drift direction. The local electron temperature T_(e,div) decreases to around 10 eV. The fraction of the divertor radiation loss was comparable. Under a relatively symmetric power flow into the outer and inner divertor fans, an outboard-dominated heat load to the target P_(target) and a nearly symmetric one were observed for the ion ▽B drift towards and away from the target, respectively. This is due to the asymmetries in the recycling and radiation loss profiles. From the viewpoint of the in-out asymmetry in the heat and particle fluxes, operation with the ion VB drift away from the target plate would be desirable, provided that attached conditions are maintained. Formation of the remote radiative divertor with the radiation loss in the divertor P_(rad,div) of about 40% was achieved in the ELMy H-mode operation. The reduction of T_(e,div) (20-45 eV) is comparable to that in the L-mode.