Theory of neoclassical pressure-gradient-driven turbulence

Technical Report · Tue Nov 01 04:00:00 EST 1988

OSTI ID:6717971

Kwon, O J; Diamond, P H; Biglari, H

The nonlinear evolution and saturation of neoclassical pressure- gradient-driven turbulence (NPGDT), evolving from linearly unstable bootstrap current modes, are investigated. The theoretical model is based on '' neoclassical MHD equations'' which are valid in the banana-plateau regimes of collisionality. Modes with poloidal wavelengths shorter than radial wavelengths are shown to be suppressed. From nonlinear saturation conditions, the turbulent pressure diffusivity is determined as an eigenvalue of the renormalized equations. Levels and radial scales of turbulence are determined from the pressure diffusivity and are shown to exceed mixing length estimates by powers of a nonlinear enhancement factor. The problem of the electron heat transport due to stochastic magnetic fields driven by NPGDT is revisited. The reconsideration of the radial structure of magnetic flutter leads to estimates of the electron heat transport and magnetic fluctuation levels which differ qualitatively and quantitatively from previous calculations. 25 refs.

• Research Organization: Texas Univ., Austin (USA). Inst. for Fusion Studies
• DOE Contract Number: FG05-80ET53088; FG03-88ER53275
• OSTI ID: 6717971
• Report Number(s): DOE/ET/53088-351; IFSR-351; ON: DE89002464
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700103* -- Fusion Energy-- Plasma Research-- Kinetics
BANANA REGIME
BEAM INJECTION
CHARGE TRANSPORT
ELECTRIC FIELDS
EQUILIBRIUM
MHD EQUILIBRIUM
NEOCLASSICAL TRANSPORT THEORY
NEUTRAL ATOM BEAM INJECTION
NONLINEAR PROBLEMS
PRESSURE GRADIENTS
TRANSPORT THEORY
TRAPPING
TURBULENCE