3-D Localized Reconnection in TS-3/4 Merging Experiments
Abstract
The laboratory experiment of three-component magnetic reconnection has been developed in TS-3 merging experiment by use of two colliding spheromaks and tokamaks (Y. Ono et al. Phys. Rev. Letts. 76), 3328, (1996).. Recently, local measurement of current sheet revealed that (1) particle aspect of reconnection and (2) 3-D local reconnection are important to explain various fast reconnection whose speed is 5-50 times larger than the Sweet-Parker reconnection. The TS-3 merging device is unique because its fast acceleration coils can demonstrate high-speed plasma inflow v_in even exceeding the ion thermal speed v_th. High resolution (up to 1/10 of sheet width) field measurement clearly indicates that anomalous resistivity of current sheet appears significantly right after the sheet width is compressed shorter than the ion gyroradius ρ_i. When v_in is decreased down to ≈1/3 v_th, the sheet width was found to stay around ρ_i. Further acceleration of plasma inflow revealed 3-D localized reconnection, breaking axisymmetry of the CT merging. Measured axial contours of the current sheet indicates that the localized reconnection initiates at a specific toroidal position and propagates toroidally recovering the symmetry. This localized reconnection can be a new fast reconnection mechanism and tends to appear when external toroidal field is small or zero under high-speed inflow condition.
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- November 1998
- Bibcode:
- 1998APS..DPP.K6S49M