Studies of Large, Non-Circular Reversed Field Pinch Discharges
A. Almagri, S. Assadi, R. N. Dexter, S. C. Prager, J.
S. Sarff, J. C. Sprott
Department of Physics, University
of Wisconsin, Madison, Wisconsin, United States of America
(Manuscript received 25 March 1987, Final manuscript received 1 July
Reversed field pinch (RFP) discharges have been produced in a large
metre major radius, 0.56 metre average minor radius), thick walled (5
aluminum vacuum vessel with indented sides. The discahrges are
and ramped up to a current of 300 kA over a time of 10 ms. Reversal is
sustained for >~10 resistive diffusion times, despite the presence
magnetic fluctuations. The influence of the bad poloidal magnetic
on RFP stability is examined by measurement of magnetic fluctuations
the plasma edge in the separate bad and good curvature regions of the
plasma for RFP and non-reversed discharges with an edge safety factor,
qa of 0.4 and 1.4. For qa ~ 1.4 discharges, the poloidal field
is small. the large device size permits RFP startup at a low toroidal
voltage (<~ 200 V), which is applied to a gap exposed to plasma, but
successfully protected against arcing (up to 300 V). RFP plasmas have
been obtained with a toroidal limiter.
Ref: A. Almagri, S. Assadi, R. N. Dexter, S. C. Prager, J. S. Sarff,
C. Sprott, Nuclear Fusion 27, 1795-1803 (1987)
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