Magnetohydrodynamic calculations with a nonmonotonic q profile and equilibrium, sheared toroidal flow

Technical Report · Wed Jul 01 04:00:00 EDT 1998

DOI:https://doi.org/10.2172/307907· OSTI ID:307907

Held, E D ^[1]; Leboeuf, J N; Carreras, B A ^[2]

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1. Univ. of Wisconsin, Madison, WI (United States). Center for Plasma Theory and Computation
2. Oak Ridge National Lab., TN (United States). Fusion Energy Div.

The linear and nonlinear stability of a nonmonotonic q profile is examined using a reduced set of magnetohydrodynamic (MHD) equations with an equilibrium, sheared toroidal flow. The reversed shear profile is shown to be unstable to a rich variety of resistive MHD modes including pressure-driven instabilities and tearing instabilities possessing a tearing/interchange character at low Lundquist number, S, and taking on a double/triple tearing structure at high S. Linear calculations show that the destabilizing effect of toroidal velocity shear on tearing modes is enhanced at finite pressure seen previously for tearing modes at high S. Nonlinear calculations show the generation of a large, m = 1, n = 0, Reynolds-stress-driven poloidal flow in the absence of significant flow damping. Calculations in which the poloidal flow was heavily damped show that sub-Alfvenic, sheared toroidal flows have a minimal effect on weakly-coupled, localized instabilities.

• 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)
• OSTI ID: 307907
• Report Number(s): UW-CPTC--98-9; ON: DE99001534
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
INSTABILITY GROWTH RATES
MAGNETOHYDRODYNAMICS
NONLINEAR PROBLEMS
PLASMA DRIFT
PRESSURE DEPENDENCE
SHEAR
TEARING INSTABILITY
TOKAMAK DEVICES