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Title: Effect of drifts on the diffusion of runaway electrons in tokamak stochastic magnetic fields

Journal Article · · Physics of Fluids B; (United States)
DOI:https://doi.org/10.1063/1.860431· OSTI ID:5504150
;  [1]
  1. Lodestar Research Corporation, Boulder, Colorado 80301 (United States)

The quasilinear diffusion of runaway electrons in tokamak stochastic magnetic fields is examined. Previous models are generalized with respect to the spatial location and coherency of the perturbing magnetic fields, treatment of the radial as well as poloidal drift motion of the electrons, and the role of sidebands that arise from the beating of the electron drift motion with the applied perturbing fields. It is found that drift effects act to reduce the level of quasilinear diffusion by an amount that depends on the poloidal distribution of the magnetic turbulence. The results are employed to estimate the internal magnetic fluctuation levels at the edge during recent experiments on the TEXT tokamak (Phys. Fluids B {bold 3}, 2038 (1991)), where the drift modification effects are shown to be small. It is inferred that intrinsic magnetic turbulence controls runaway diffusion, but not the thermal diffusivity of the background electrons.

DOE Contract Number:
FG02-88ER53263
OSTI ID:
5504150
Journal Information:
Physics of Fluids B; (United States), Vol. 4:1; ISSN 0899-8221
Country of Publication:
United States
Language:
English