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 we develop a computational model for these modes in the cylindrical tokamak approximation and explore the linear growth and single-helicity quasi-linear saturation phases of the rippling modes for parameters appropriate to the edge of a tokamak plasma. Large parallel heat conduction does not stabilize these modes; it only reduces their growth rate by a factor scaling as k/sub parallel//sup -4/3/. 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 Vector E x Vector 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:
- 5155019
- Report Number(s):
- ORNL/TM-7989; ON: DE82007724; TRN: 82-014504
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
TOKAMAK DEVICES
MAGNETIC FIELD RIPPLES
PLASMA SHEATH
INSTABILITY GROWTH RATES
QUASILINEAR PROBLEMS
SCALING LAWS
THERMAL CONDUCTION
TURBULENCE
CLOSED PLASMA DEVICES
ENERGY TRANSFER
HEAT TRANSFER
MAGNETIC FIELD CONFIGURATIONS
THERMONUCLEAR DEVICES
700107* - Fusion Energy- Plasma Research- Instabilities
700202 - Fusion Power Plant Technology- Magnet Coils & Fields