PARALLEL CURRENTS IN THE SCRAPE-OFF LAYER OF HIGH-DENSITY JT-60U DISCHARGES

Parallel currents passing between the two strike zones in the scrape-o ff layer of single-null divertor discharges (SOL current) have been in vestigated in JT-60U high-density discharges. Under the detached diver tor condition and during the X-point MARFE, the in-out asymmetry in el ectron temperature T-e(div) on the divertor plate was reversed compare d with attached cases. At the same time, the direction of the SOL curr ent was also reversed. The observed direction of SOL currents correspo nded to the direction of thermoelectric currents, which flow from the high T-e(div) side to the low T-e(div) side. Under the detached divert or condition and during the X-point MARFE, the magnitude of SOL curren ts at the outboard target was much larger than that at the inboard tar get, and also than that predicted by the thermoelectric current theory .