Nonlinear evolution of magnetic islands in a two fluid torus

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:489400

Sugiyama, L E ^[1]; Park, W ^[2]

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1. Massachusetts Institute of Technology, Cambridge, MA (United States)
2. Princeton Plasma Physics Lab., NJ (United States)

A numerical model MH3D-T for the two fluid description of macroscopic evolution in a full three dimensional torus has been developed. Based on the perturbative drift ordering, generalized to arbitrary perturbation size, the model follows the full temperature evolution, including the thermal equilibration along the magnetic field. It contains the diamagnetic drifts, ion gyroviscous stress tensor, and the Hall term in Ohm`s law. Electron inertia is neglected. The numerical model solves the same equations in a torus and in several simplified configurations. It has been benchmarked against the diamagnetic {omega}*{sub i} stabilization of the resistive m = 1, n = 1 reconnecting mode in a cylinder. The nonlinear evolution of resistive magnetic islands with m,n {ne} 1,1 in a cylinder is found to agree with previous analytic and reduced-torus results, which show that the diamagnetic rotation vanishes early in the island evolution and the saturated island size is determined by the same external driving factor {Delta}{prime} as in MHD. The two fluid evolution in a full torus, however, differs from that in a cylinder and from the resistive MHD evolution. The poloidal rotation velocity undergoes a degree of poloidal momentum damping in the torus, even without neoclassical effects. The two fluid magnetic island grows faster, nonlinearly, than the resistive MHD island, and also couples different toroidal harmonics more effectively. Plasma compressibility and processes operating along the magnetic field play a much more important role than in MHD or in simple geometry. The two fluid model contains all the important neoclassical fluid effects except for the b {circ}{del} {circ}{Pi}{sub {parallel}j} viscous force terms. The addition of these terms is in progress.

• OSTI ID: 489400
• Report Number(s): CONF-960354--
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
FLOW MODELS
MAGNETIC ISLANDS
MHD EQUILIBRIUM
NONLINEAR PROBLEMS
PLASMA FLUID EQUATIONS
TOROIDAL CONFIGURATION