Spectrum of ballooning instabilities in a stellarator
The recent revival of interest in the application of the 'ballooning formalism' to low-frequency plasma instabilities has prompted a comparison of the Wentzel-Kramers-Brillouin (WKB) ballooning approximation with an (in principle) exact normal mode calculation for a three-dimensional plasma equilibrium. Semiclassical quantization, using the ideal magnetohydrodynamic (MHD) ballooning eigenvalue to provide a local dispersion relation, is applied to a ten-field period stellarator test case. Excellent qualitative agreement, and good quantitative agreement is found with predications from the TERPSICHORE code (D.V. Anderson et al., Int. J. Supercomput. Appl. 4, 34, 1990) for toroidal mode numbers from 1 to 14 and radial mode numbers from 0 to 2. The continuum bands predicted from three-dimensional WKB theory are too narrow to resolve.
Bibliographic Reference: Article: Phys. Plasmas, Vol. 3 (1996) No. 1, pp. 275-280
Record Number: 199610260 / Last updated on: 1996-03-18
Original language: en
Available languages: en