Effects of nonlinear electron dynamics in a fluid model of collisionless trapped-electron mode turbulence
The role of the electron nonlinearity on saturation levels and particle transport in collisionless trapped electron mode turbulence is examined numerically using a two-dimensional fluid model. It is found that the removal of the electron nonlinearity results in an order of magnitude [ital increase] in fluctuation and particle transport levels. In addition, the qualitative behavior of the saturated state changes distinctly, including a decrease in RMS wave number in both cross-field directions, deviations from isotropy, changes in transport scalings, and changes in the spectral flow of energy. These results indicate that the electron nonlinearity is responsible for an efficient transfer of internal energy to small dissipation scales, thus resulting in lower fluctuation levels than predicted by ion mode coupling alone. The electron nonlinearity also decreases the phase angle between the density and potential leading to a decrease in the driving source. These results underscore the importance of the cross-correlation on saturation and demonstrate that numerical or theoretical use of [ital i][delta]'' models to describe weakly collisional or collisionless trapped-electron mode turbulence is not appropriate.
- Publication Date:
- OSTI Identifier:
- DOE Contract Number:
- FG03-88ER53275; W-7405-ENG-48
- Resource Type:
- Journal Article
- Resource Relation:
- Journal Name: Physics of Plasmas; (United States); Journal Volume: 1:6
- Country of Publication:
- United States
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; TRAPPED ELECTRONS; TURBULENCE; COLLISIONLESS PLASMA; ENERGY SPECTRA; ENERGY TRANSFER; NONLINEAR PROBLEMS; TOKAMAK DEVICES; TRANSPORT THEORY; CLOSED PLASMA DEVICES; ELECTRONS; ELEMENTARY PARTICLES; FERMIONS; LEPTONS; PLASMA; SPECTRA; THERMONUCLEAR DEVICES 700340* -- Plasma Waves, Oscillations, & Instabilities-- (1992-); 700330 -- Plasma Kinetics, Transport, & Impurities-- (1992-)
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