Tearing mode analysis in tokamaks, revisited

Technical Report · Mon Dec 01 04:00:00 EST 1997

DOI:https://doi.org/10.2172/656700· OSTI ID:656700

Nishimura, Y; Callen, J D; Hegna, C C

A new {Delta}{prime} shooting code has been developed to investigate tokamak plasma tearing mode stability in a cylinder and large aspect ratio ({epsilon} {le} 0.25) toroidal geometries, neglecting toroidal mode coupling. A different computational algorithm is used (shooting out from the singular surface instead of into it) to resolve the strong singularities at the mode rational surface, particularly in the presence of finite pressure term. Numerical results compare favorably with Furth et al. results. The effects of finite pressure, which are shown to decrease {Delta}{prime}, are discussed. It is shown that the distortion of the flux surfaces by the Shafranov shift, which modifies the geometry metric element stabilizes the tearing mode significantly, even in a low {beta} regime before the toroidal magnetic curvature effects come into play. Double tearing modes in toroidal geometries are examined as well. Furthermore, m {ge} 2 tearing mode stability criteria are compared with three dimensional initial value MHD simulation by the FAR code.

• Research Organization: Univ. of Wisconsin, Center for Plasma Theory and Computation, Madison, WI (United States)
• Sponsoring Organization: USDOE Office of Energy Research, Washington, DC (United States)
• DOE Contract Number: FG02-86ER53218
• OSTI ID: 656700
• Report Number(s): UW-CPTC--97-21; ON: DE98003891
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ALGORITHMS
BOUNDARY-VALUE PROBLEMS
COMPARATIVE EVALUATIONS
NUMERICAL ANALYSIS
PRESSURE DEPENDENCE
TEARING INSTABILITY
TOKAMAK DEVICES