Abstract
Transient effect of fast magnetic reconnection was investivated in TS-4 torus plasma merging device. Reconnection speed of two merging tokamaks under low inflow and strong guiding(toroidal) field B⊥ agrees with the theoretical value for the Sweet-Parker model. However, when current-sheet was compressed by two pairs of acceleration coils, the reconnection speed became three times as much as the value for the Sweet-Parker model under constant resistivity of the sheet. The inflow flux was found to exceed the outflow flux, indicating density piled-up in current sheet. The measured inflow speed is consistent with a new model where the flux pile-up effect is inclued in convensional Sweet-Parker model.
