Analytic theory of the nonlinear m = 1 tearing mode
Numerical studies show that the m = 1 tearing mode continues to grow exponentially well into the nonlinear regime, in contrast with the slow, ''Rutherford,'' growth of m>1 modes. A single helicity calculation is presented which generalizes that of Rutherford (Phys. Fluids 16, 1903 (1973)) to the case when the constant-psi approximation is invalid. As in that theory, the parallel current becomes an approximate flux function when the island size W exceeds the linear tearing layer width. However, for the m = 1 mode, W becomes proportional to deltaB, rather than (deltaB)/sup 1//sup ///sup 2/ above this critical amplitude. This implies that the convective nonlinearity in Ohm's law, which couples the m = 0 component to the m = 1 component, dominates the resistive diffusion term. The balance between the inductive electric field and this convective nonlinearity results in exponential growth. Assuming the form of the perturbed fields to be like that of the linear mode, we find that growth occurs at 71% of the linear rate.
- Research Organization:
- Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 78712-1068
- DOE Contract Number:
- FG05-80ET53088
- OSTI ID:
- 5791514
- Journal Information:
- Phys. Fluids; (United States), Vol. 29:5
- Country of Publication:
- United States
- Language:
- English
Similar Records
A new algebraic growth of nonlinear tearing mode
Current sheets and nonlinear growth of the m =1 kink-tearing mode
Related Subjects
PLASMA
TEARING INSTABILITY
AMPLITUDES
CONVECTION
HELICITY
MAGNETIC ISLANDS
NONLINEAR PROBLEMS
NUMERICAL SOLUTION
OHM LAW
OSCILLATION MODES
SIZE
TOKAMAK DEVICES
CLOSED PLASMA DEVICES
ENERGY TRANSFER
HEAT TRANSFER
INSTABILITY
MAGNETIC FIELD CONFIGURATIONS
MASS TRANSFER
PARTICLE PROPERTIES
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
THERMONUCLEAR DEVICES
700108* - Fusion Energy- Plasma Research- Wave Phenomena
700107 - Fusion Energy- Plasma Research- Instabilities