Statistical analysis to the SOL plasma fluctuation in JT-60U

Intermittent events and their temporal scale were studied in the L-mode SOL plasma by applying statistical analysis of probability distribution function and conditional average to j s and V f measured with the Mach probes at the HFS and LFS. Fluctuation level was large (20-70%) at the LFS midplane, compared to those near the X-point (4-20%) and the HFS SOL (4-10%). 'Burst events' were measured mostly at the LFS midplane, where positive skewness (S=0.3-0.8) extended from the separatrix to the far SOL (r mid < 10 cm). Time scale of the'burst events' was short (∼5 μs). When the divertor plasma was detached up to the vicinity of the X-point, large 'burst events' characterized by S ∼ 1.8 and long time scale of 40-80 μs occurred in the outer SOL near the X-point (0.5 < r mid < 1.5 cm). The large 'burst events' can therefore be considered as a candidate mechanism to enhance the radial transport and SOL flow in the divertor.