Nonlinear dynamics of single-helicity neoclassical MHD tearing instabilities

Technical Report · Sat Oct 01 00:00:00 EDT 1988

DOI:https://doi.org/10.2172/7079859· OSTI ID:7079859

Spong, D. A.; Shaing, K. C.; Carreras, B. A.; Callen, J. D.; Garcia, L.

Neoclassical magnetohydrodynamic (MHD) effects can significantly alter the nonlinear evolution of resistive tearing instabilities. This is studied numerically by using a flux-surface-averaged set of evolution equations that includes the lowest-order neoclassical MHD effects. The new terms in the equations are fluctuating bootstrap current, neoclassical modification of the resistivity, and neoclassical damping of the vorticity. Single-helicity tearing modes are studied in a cylindrical model over a range of neoclassical viscosities (..mu../sub e//..nu../sup e/) and values of the ..delta..' parameter of tearing mode theory. Increasing the neoclassical viscosity leads to increased growth rate and saturated island width as predicted analytically. The larger island width is caused by the fluctuating bootstrap current contribution in Ohm's law. The ..delta..' parameter no longer solely determines the island width, and finite-width saturated islands may be obtained even when ..delta..' is negative. The importance of the bootstrap current (/approximately/par. delta/rho///partial derivative/psi/) in the nonlinear dynamics leads us to examine the sensitivity of the results with respect to different models for the density evolution. 11 refs., 8 figs.

• Research Organization: Oak Ridge National Lab., TN (USA)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 7079859
• Report Number(s): ORNL/TM-10947; ON: DE89001960
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700107* -- Fusion Energy-- Plasma Research-- Instabilities
CLOSED PLASMA DEVICES
CONFINEMENT
DIFFERENTIAL EQUATIONS
EQUATIONS
EQUATIONS OF MOTION
EQUILIBRIUM
INSTABILITY
MHD EQUILIBRIUM
NEOCLASSICAL TRANSPORT THEORY
NONLINEAR PROBLEMS
PARTIAL DIFFERENTIAL EQUATIONS
PLASMA CONFINEMENT
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
TEARING INSTABILITY
THERMONUCLEAR DEVICES
THREE-DIMENSIONAL CALCULATIONS
TOKAMAK DEVICES
TRANSPORT THEORY