Nonlinear inward particle flux component in trapped electron mode turbulence

Journal Article · Thu Jun 15 00:00:00 EDT 2006 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2212403· OSTI ID:20787357

Terry, P W; Gatto, R ^[1]

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1. University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

Trapped electron turbulence is shown to have a significant inward particle flux component associated with nonlinear deviations of the density-potential cross correlation from the quasilinear value. The cross correlation is altered because the density advection nonlinearity mixes a linearly stable eigenmode with the eigenmode of the instability. The full nonlinear flux is evaluated by solving spectrum balance equations in a complete basis spanning the fluctuation space. An ordered expansion for small collisionality, perpendicular wave number, and temperature/density-gradient instability threshold parameter enables an analytic solution for a weakly driven regime. The solution quantifies the role of zonal modes on transport via their saturation of the turbulence under intensely anisotropic transfer. The inward transport is neither diffusive nor convective, but is driven by temperature gradient and enhanced by flat density gradients. It is slightly smaller than the outwardly directed flux associated with the growing eigenmode, making the flux a small fraction of the quasilinear value.

• OSTI ID: 20787357
• Journal Information: Physics of Plasmas, Vol. 13, Issue 6; Other Information: DOI: 10.1063/1.2212403; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ADVECTION
ANALYTICAL SOLUTION
ANISOTROPY
CORRELATIONS
ELECTRON COLLISIONS
ELECTRON TEMPERATURE
EXPANSION
FLUCTUATIONS
ION COLLISIONS
ION TEMPERATURE
NONLINEAR PROBLEMS
PLASMA
PLASMA DENSITY
PLASMA INSTABILITY
RADIATION TRANSPORT
TEMPERATURE GRADIENTS
TRAPPED ELECTRONS
TURBULENCE