Heat and particle transport of SOL and divertor plasmas in the W shaped divertor on JT-60U

The geometry effects of the W shaped divertor on the divertor plasma were i nvestigated quantitatively. The ion flux was increased near the divertor st rike point, which is effective for reducing the local electron temperature and decreasing the onset (n) over bar(e) of divertor detachment. The plasma profile and parallel plasma flow in the scrape-off layer were systematical ly measured using reciprocating Mach probes installed at the midplane and t he divertor X point. For the ion del B drift direction towards the divertor , 'flow reversal' was observed at the midplane. A quantitative evaluation o f the parallel plasma flow suggesting that the flow is produced in a torus to keep the pressure constant along the field lines was consistent with the measurements.