Current Sheet Dynamics of High Guide-Field Magnetic Reconnection

We measured detailed current sheet dynamics of two merging high-guide field flux tubes using newly developed high-resolution magnetic field measurement by Printed-Circuit-Board (PCB) coils in TS-6 merging tokamak experiment. We found that the sheet ejection occurred twice, increasing their merging ratio, the toroidal current density Jt, the toroidal electric field Et, and the effective resistivity η of current sheet. The possible explanation for this result is that the mass ejection from the current sheet drives the reconnection inflow, due to the mass conservation law. Especially, after the second sheet ejection, the effective resistivity increased significantly, probably because the sheet thickness compressed up to the ion Larmor radius.