Trapped electron transport via microinstabilities

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:6748725

Hu, Y

Anomalous electron thermal conduction is generally recognized to be the principal heat loss channel in most modern tokamaks. Turbulent drift type microinstabilities have long been suspected to be the primary cause of this anomalous thermal conduction. In this work, a systematic formulation of trapped-electron transport is presented, based on a drift-wave turbulence model in the good confinement region (between the q = 1 and q = 2 surfaces). A pre-existing nonlinear gyrokinetic formalism was extended to include collisional effects by using the Fokker-Planck collision operator. Following the procedures of neoclassical theory, a formal transport theory including turbulence is developed. To further explore the properties of the low-..beta.. gyrokinetic Fokker-Planck equation, the author considers the specific case of an axisymmetric, large aspect ratio tokamak with circular, concentric magnetic surfaces and employs the ballooning mode representation for the fluctuating quantities. The resulting equation is solved analytically for the perturbed electron distribution function. Corresponding expressions for the fluxes of particles and energy are evaluated numerically after prescribing the mode structure along the field line and the saturated mode amplitudes. Electrostatic transport coefficients thus obtained are presented and found to be in agreement with previous heuristic arguments.

• Research Organization: Princeton Univ., NJ (USA)
• OSTI ID: 6748725
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700103 -- Fusion Energy-- Plasma Research-- Kinetics
700107* -- Fusion Energy-- Plasma Research-- Instabilities
CLOSED PLASMA DEVICES
DIFFERENTIAL EQUATIONS
DRIFT INSTABILITY
ELECTRONS
ELEMENTARY PARTICLES
EQUATIONS
FERMIONS
FOKKER-PLANCK EQUATION
INSTABILITY
LEPTONS
NEOCLASSICAL TRANSPORT THEORY
PARTIAL DIFFERENTIAL EQUATIONS
PLASMA DRIFT
PLASMA INSTABILITY
PLASMA MICROINSTABILITIES
PLASMA WAVES
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TRANSPORT THEORY
TRAPPED ELECTRONS
TURBULENCE