Plasma flow measurement in high- and low-field-side SOL and influence on the divertor plasma in JT-60U

Three reciprocating Mach probes were installed at the high-field-side (HFS) baffle, low-field-side (LFS) midplane and just below the X-point in JT-60U tokamak in order to investigate the SOL flow pattern. Profiles of particle fluxes produced by parallel SOL flow and Er×B-drift flow were evaluated from Mach number, electron temperature, density and floating potential. The drift particle flux was dominant near the separatrix, while it became smaller than the parallel particle flux at the outer flux surfaces. Total particle fluxes towards HFS and LFS divertors were investigated at various plasma densities. The drift flux was comparable to the parallel flux at relatively low densities, while the parallel flux became dominant at high densities. Drift flux in the private flux region was also evaluated, and it contributed to produce in–out asymmetries in the divertor ion flux and particle recycling under attached divertor condition.