Vertical and Kink Mode Stability Calculations for Current Carrying Quasiaxial Stellarators
Vertical and kink mode stability are essential for strongly shaped tokamaks, to preclude disruptive plasma termination. Similarly, the design of stellarators with significant current, such as quasiaxial stellarators (QAS) must be carefully examined to ensure adequate vertical and kink stability. The CAS3D [1] and TERPSICHORE [2] MHD stability code packages are being used to evaluate the stability of QAS configurations. CAS3D has previously been applied to predict stability of the W7-X stellarator, under construction at IPP, Greifswald, Germany. As part of a multifaceted effort to develop an interesting compact quasiaxial stellarator configuration for a modest sized experiment at PPPL, these two code packages are being used for three dimensional calculations of internal and external MHD stability, including extensive benchmarking of MHD stability for axisymmetric and nonaxisymmetric cases. Optimized configurations have been identified for the proposed NCSX experiment which are stable to ballooning, kink and the periodicity-preserving modes and have acceptable confinement. Neoclassical particle transport is being studied and optimized for good confinement [7]. The three dimensional global ideal MHD stability code packages CAS3D and TERPSICHORE are found in agreement in numerous benchmarking studies and both predict global stability for the NCSX design point configuration. CAS3D has extended TERPSICHORE calculations for NCSX showing stability of the kink and periodicity-preserving modes for this stellarator even without a conducting wall. There is still a need for comprehensive comparisons of detailed measurements of MHD instabilities to results of global stability calculations for both rippled tokamak and stellarator experiments.
- Research Organization:
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- AC02-76CH03073
- OSTI ID:
- 8835
- Report Number(s):
- PPPL-3351; ON: DE00008835
- Country of Publication:
- United States
- Language:
- English
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