Polarized radial magnetic fields and outward plasma fluxes during shallow-reversal discharges in the ZT-40M reversed-field pinch
The characteristics of edge-region electromagnetic disturbances and of pulsed radial fluxes of plasma to the liner as well as the detailed interrelationship among these processes have been studied on the ZT-40M reversed-field pinch in its normal, shallow-reversal operating regime. The dominant magnetic disturbances are spiky (pulsewidth approx.5--10 ..mu..s) low-amplitude (Vertical BarB/sub r//B/sub theta/Vertical Bar< or approx. =10/sup -2/)= poloidally symmetric radial-field structures intersecting the vacuum wall and precessing toroidally in the anti-I/sub phi/ sense. The effect of even slight toroidal-field reversal (Vertical BarB/sub phi/(a)Vertical Barroughly-equalB/sub theta/(a)/10) is to polarize these radial-field spikes preferentially positive (i.e., B/sub r/>0) and to increase the speed of the minority (B/sub r/<0) while decreasing the speed of the majority (B/sub r/>0) spikes. Synchronous with the polarized B/sub r/ spikes are intense radially outward fluxes of plasma (instantaneously > or approx. =10/sup 22/ m/sup -2/ s/sup -1/) leading to recurrent, large amplitude (Vertical Bar..delta..n/n> or approx. =25%) depletion of the density in the outer quarter of minor radius. The resulting time-averaged global loss-rate per particle is significant (approx.10/sup 3/ s/sup -1/).
- Research Organization:
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545
- OSTI ID:
- 5385158
- Journal Information:
- J. Appl. Phys.; (United States), Vol. 55:1
- Country of Publication:
- United States
- Language:
- English
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