Calculation of ideal MHD growth rate with compressibility for three-dimensional stellarator plasmas
The first results of full 3-D calculations of ideal MHD growth rates with finite compressibility for stellarator plasmas are presented. In previous studies the incompressibility condition was assumed, so that only the stability index could be calculated. The full compressional terms have now been incorporated into the 3-D linear ideal MHD code TERPSICHORE, which can calculate the physical growth rate. The new code has been benchmark tested against known stability results of the 2-D axisymmetric Solov'ev equilibrium. It has also been applied to truly 3-D stellarator equilibria and physical growth rates were obtained. Preliminary results indicate that it is essential to decouple sound waves from shear Alfvén waves in order to obtain accurate results. The number of Fourier modes needed to ensure convergence is, therefore, substantially broadened. Various numerical aspects of the new code are discussed, as well as a tunable integration finite element method, which has been implemented in the code. This method has been shown to suppress numerically destabilised continuum modes near resonance surfaces, which are induced by the hybrid finite element method. Detailed results and applications to the proposed LHD device are presented.
Bibliographic Reference: Article: 1991 International Sherwood Fusion Conference (1991) p. 2C29
Record Number: 199111315 / Last updated on: 1994-12-02
Original language: en
Available languages: en