Electron and ion heating characteristics during magnetic reconnection in MAST

Localized electron heating at X point and global ion heating in the downstream during merging/reconnection startup of ST in MAST have been studied in detail using 130 channel YAG- and 300 channel Ruby-Thomson scattering measurement and a new 32 chord ion Doppler tomography diagnostics. In addition to the previously achieved record heating of $\sim$1keV, 2D profile of electron temperature revealed highly localized heating structure at X point with the characteristic scale length of 0.02-0.05m $< c/\omega_{pi}$, while the ion temperature increases in the downstream of outflow jet with the width of $c/\omega_{pi}\sim0.1$m where reconnected field forms thick layer of closed flux surface. The effect of $T_i-T_e$ energy relaxation also affects both heating profiles in MAST, finally the formation of triple peak structure for both profiles was observed with the delay of $\tau^{E}_{ei}$. The toroidal guide field mostly contributes to the formation of a localized electron heating structure at the X point but not to bulk ion heating downstream.