Nonlinear coupling of tearing modes with self-consistent resistivity evolution in tokamaks
The nonlinear interaction of tearing modes of different helicity in tokamaks is studied for realistic values of resistivity and parallel heat conduction. The self-consistent evolution of the resistivity is taken into account through the electron heat conduction equation. For equilibrium q profiles inferred from electron temperature profiles measured before a tokamak disruption, the essential result is that the (m=2;n=1) mode nonlinearly destabilizes other modes on a rapid time scale. Because of the development of magnetic islands of different helicity, the toroidal current density is severely deformed. These islands overlap and field lines become stochastic in a sizable plasma volume, flattening the temperature profile in this region through parallel heat transport. The deformation of the toroidal current produces a rapid decrease in the self-inductance of the plasma, and the voltage at the limiter decreases, becoming increasingly negative. An extensive survey of equilibria and initial conditions has been conducted and a simple prescription for their nonlinear stability properties is given.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 5048704
- Journal Information:
- Phys. Fluids; (United States), Vol. 23:9
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
TEARING INSTABILITY
NONLINEAR PROBLEMS
TOKAMAK TYPE REACTORS
COMPUTER CODES
CURRENT DENSITY
CYLINDRICAL CONFIGURATION
ELECTRIC CONDUCTIVITY
ELECTRON TEMPERATURE
FINITE DIFFERENCE METHOD
FOURIER ANALYSIS
MAGNETIC ISLANDS
MAGNETOHYDRODYNAMICS
PLASMA INSTABILITY
PLT DEVICES
THERMAL CONDUCTION
THREE-DIMENSIONAL CALCULATIONS
CONFIGURATION
ELECTRICAL PROPERTIES
ENERGY TRANSFER
FLUID MECHANICS
HEAT TRANSFER
HYDRODYNAMICS
INSTABILITY
ITERATIVE METHODS
MAGNETIC FIELD CONFIGURATIONS
MECHANICS
NUMERICAL SOLUTION
PHYSICAL PROPERTIES
PLASMA MACROINSTABILITIES
THERMONUCLEAR REACTORS
700107* - Fusion Energy- Plasma Research- Instabilities