High Beta Equilibrium Transition of Merging CTs and Their Particle Confinement in TS-3/4 Merging Experiments
Abstract
High-power heating of compact toroids (CTs: ST, Spheromak, RFP and FRC) was demonstrated in TS-3 merging experiment. The heating power of merging reaches up to 10 MW, even if the present CTs with major radii ~ 0.2 m have small thermal energy ~ 20 J. Maximum heating energy ~ 100 J was obtained when initial CTs have q values as low as 0.5 (Spheromak). An important finding is that this significant heating changes the toroidal current profiles from peaked to hollow sustaining the higher plasma thermal pressure. The β value was observed to increase from 5-10 % up to 60 %. A question is how the plasma particle of CTs behaves during and after the heating. Ion motion was measured directly using local injection of carbon ion. The pulsed ruby laser was used to strike carbon chip installed in the plasma. Time evolutions of injected carbon particle will be measured by a high-speed streak camera to evaluate the heating mechanism and the particle confinement of those CTs. Further high-power heating experiment is planned using the world-largest merging device TS-4 whose plasma size and field is about 2-3 times larger than TS-3 CTs'. Its better confinement and lower radiation loss will make it easier to elucidate the heating mechanism of merging and also to compare the particle confinement of various CTs.
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- November 1998
- Bibcode:
- 1998APS..DPP.G4S50U