Reconnection rates of magnetic fields

Technical Report · Sun May 01 00:00:00 EDT 1983

DOI:https://doi.org/10.2172/6242852· OSTI ID:6242852

Park, W; Monticello, D A; White, R B

The Sweet-Parker and Petschek scalings of magnetic reconnection rate are modified to include the effect of the viscosity. The modified scalings show that the viscous effect can be important in high-..beta.. plasmas. The theoretical reconnection scalings are compared with numerical simulation results in a tokamak geometry for three different cases: a forced reconnection driven by external coils, the nonlinear m = 1 resistive internal kink, and the nonlinear m = 2 tearing mode. In the first two cases, the numerical reconnection rate agrees well with the modified Sweet-Parker scaling, when the viscosity is sufficiently large. When the viscosity is negligible, a steady state which was assumed in the derivation of the reconnection scalings is not reached and the current sheet in the reconnection layer either remains stable through sloshing motions of the plasma or breaks up to higher m modes. When the current sheet remains stable, a rough comparison with the Sweet-Parker scaling is obtained. In the nonlinear m = 2 tearing mode case where the instability is purely resistive, the reconnection occurs on the slower dissipation time scale (Psi/sub s/ approx. eta). In addition, experimental data of the nonlinear m = 1 resistive internal kink in tokamak discharges are analyzed and are found to give reasonable agreement with the modified Sweet-Parker scaling.

• Research Organization: Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 6242852
• Report Number(s): PPPL-2014; ON: DE83013719
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
TOKAMAK DEVICES
MAGNETIC FIELD CONFIGURATIONS
KINK INSTABILITY
NONLINEAR PROBLEMS
SCALING LAWS
TEARING INSTABILITY
VISCOSITY
CLOSED PLASMA DEVICES
INSTABILITY
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
THERMONUCLEAR DEVICES
700202* - Fusion Power Plant Technology- Magnet Coils & Fields