Merging Formation and Current Drive of FRC in TS-3 Device and Initial Operation of TS-4 Merging/ULART Device
Abstract
Novel merging formation of the field-reversed configuration (FRC) has been developed in the TS-3 merging experiment, leading us to a new scenario of FRC slow-formation, heating and current-amplification. Two force-free spheromaks with opposing toroidal field were merged together in the axial direction to form a high-β (>70%) FRC with ion temperature up to 200eV[1]. A center ohmic heating (OH) coil was used to amplify the FRC by factor 2-3 and to sustain its current over 300μ sec. This new FRC formation scheme leads us to construction of the world-largest spheromak/tokamak merging device TS-4. Its cylindrical vacuum vessel with diameter of 1.9m and length of 2.5m has two torus plasma formation coils, two plasma guns, a center OH coil and separation coils, allowing us to produce four spheromaks or tokamaks on each single discharge. This flexible coil system enables us to investigate merging formation and confinement of FRC, (2) its current amplification and sustainment up to msec, (3) ULART merging for helicity injection and for profile control, (4) comparison of low-aspect-ratio (1.02-2) tokamak, RFP, spheromak and FRC, (5) laboratory experiment of magnetic reconnection. The initial operation demonstrated the formation of ultra-low-aspect-ratio (≈ 1.02) tokamak with major and minor radii of 0.5m and 0.49m. [1] Y. Ono et al., Plas. Phys. Cont. Nucl. Fus. Res 1992, 2, 619 (1992).
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- November 1997
- Bibcode:
- 1997APS..DPPhTP128O