Experimental Study of Axisymmetric Instability of Inverse-Dee and Square Tokamak Equilibria

B. Lipschultz, S. C. Prager, T. H. Osborne, J. C. Sprott, and M. Phillips
University of Wisconsin, Madison, Wisconsin 53706
(Received 21 November 1978)

ABSTRACT

Inverse-dee-- and square--shaped equilibria are observed by experimentally mapping the magnetic-flux plot as a function of time in a tokamak with a 4-null poloidal divertor. Inverse-dee equilibria are observed to be unstable to the vertical magnetohydrodynamic axisymmetric instability on a time scale ~ 1000 poloidal Alfven times. Square equilibria are stable on the time scale available for observation. Instability growth is apparently slowed by field-shaping hoop and wall passive stabilization.

Ref: B. Lipschultz, S. C. Prager, T. H. Osborne, J. C. Sprott, and M. Phillips, Phys. Rev. Lett. 43, 36-39 (1979)

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