New developments in the theory of ion-temperature-gradient driven turbulence in tokamaks

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:5588751

Mattor, N

This work considers three aspects of ion-temperature-gradient driven turbulence ( {eta}{sub i}-turbulence') in tokamaks. Chapter 1 is a primer for those not familiar with the basics of this instability. Chapter 2 presents a theory of weak {eta}{sub i}-turbulence near the threshold of instability. The model considers kinetics ions and adiabatic electrons in a sheared slab geometry. The nonlinear wave kinetic equation indicates that ion Compton scattering is the dominant nonlinear saturation process. The wave kinetic equation is reduced to a differential equation for the spectrum, from which it is shown that the energy scatters to the linearly stable low k{sub y} modes. The spectrum of fluctuation levels (peaked about k{sub {perpendicular}}{rho}{sub i} {approx equal} 1) is much lower than that suggested by naive extrapolation from the strong turbulence regime. The resulting ion thermal conductivity is similarly low, so that strong ion heating can be expected to drive the ion temperature gradient past this threshold regime. Chapter 3 presents a theory of diffusive momentum transport driven by {eta}{sub i}-turbulence, in order to investigate the relation between momentum and thermal transport in neutral-beam-heated tokamaks with subsonic toroidal rotation velocity. Chapter 4 is a study of {eta}{sub i}-turbulence in the presence of flat density profiles, relevant to the high confinement discharges ( H-modes') on the DIII-D tokamak. Chapter 5 is a summary of this work, and a list of suggestions for further investigation.

• Research Organization: Texas Univ., Austin, TX (United States)
• OSTI ID: 5588751
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700340* -- Plasma Waves
Oscillations
& Instabilities-- (1992-)
BEAM INJECTION
CHARGED PARTICLES
CLOSED PLASMA DEVICES
CONFINEMENT
DIFFERENTIAL EQUATIONS
ELECTRONS
ELEMENTARY PARTICLES
EQUATIONS
FERMIONS
H-MODE PLASMA CONFINEMENT
ION TEMPERATURE
IONS
KINETIC EQUATIONS
LEPTONS
NEUTRAL ATOM BEAM INJECTION
NONLINEAR PROBLEMS
PARTIAL DIFFERENTIAL EQUATIONS
PHYSICAL PROPERTIES
PLASMA CONFINEMENT
PLASMA SIMULATION
SIMULATION
TEMPERATURE GRADIENTS
THERMAL CONDUCTIVITY
THERMODYNAMIC PROPERTIES
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TURBULENCE
WAVE EQUATIONS