Rippling modes in the edge of a tokamak plasma
A promising resistive magnetohydrodynamic candidate for the underlying cause of turbulence in the edge of a tokamak plasma is the rippling instability. In this paper a computational model for these modes in the cylindrical tokamak approximation was developed and the linear growth and single-helicity quasi-linear saturation phases of the rippling modes for parameters appropriate to the edge of a tokamak plasma were explored. Large parallel heat conduction does not stabilize these modes; it only reduces their growth rate by a factor sacling as K/sup -4/3//sub parallel/. Nonlinearly, individual rippling modes are found to saturate by quasi-linear flattening of the resistivity profile. The saturated amplitude of the modes scales as m/sup -1/, and the radial extent of these modes grows linearly with time due to radial E x B/sub 0/ convection. This evolution is found to be terminated by parallel heat conduction.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 5223982
- Journal Information:
- Phys. Fluids; (United States), Vol. 25:7
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
OSCILLATION MODES
MATHEMATICAL MODELS
PLASMA
TURBULENCE
PLASMA INSTABILITY
AMPLITUDES
CYLINDRICAL CONFIGURATION
NONLINEAR PROBLEMS
STABILIZATION
THERMAL CONDUCTION
TOKAMAK DEVICES
CLOSED PLASMA DEVICES
CONFIGURATION
ENERGY TRANSFER
HEAT TRANSFER
INSTABILITY
THERMONUCLEAR DEVICES
700107* - Fusion Energy- Plasma Research- Instabilities
700108 - Fusion Energy- Plasma Research- Wave Phenomena