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Your search keyword '"McDevitt, C J"' showing total 3 results
Start Over Author "McDevitt, C J" Topic momentum (mechanics)
3 results on '"McDevitt, C J"'

1. Transport of parallel momentum by collisionless drift wave turbulence.

Author

Diamond, P. H., McDevitt, C. J., Gürcan, Ö. E., Hahm, T. S., and Naulin, V.

Subjects
*TURBULENCE, *MOMENTUM (Mechanics), *DRIFT waves, *RESONANCE, *BIFURCATION theory
Abstract

This paper presents a novel, unified approach to the theory of turbulent transport of parallel momentum by collisionless drift waves. The physics of resonant and non-resonant off-diagonal contributions to the momentum flux is emphasized, and collisionless momentum exchange between waves and particles is accounted for. Two related momentum conservation theorems are derived. These relate the resonant particle momentum flux, the wave momentum flux and the refractive force. A perturbative calculation, in the spirit of Chapman-Enskog theory, is used to obtain the wave momentum flux, which contributes significantly to the residual stress. A general equation for mean κ∥(<κ∥>) is derived and used to develop a generalized theory of symmetry breaking. The resonant particle momentum flux is calculated, and pinch and residual stress effects are identified. The implications of the theory for intrinsic rotation and momentum transport bifurcations are discussed. [ABSTRACT FROM AUTHOR]

Published
2008
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2. Poloidal rotation and its relation to the potential vorticity flux.

Author

McDevitt, C. J., Diamond, P. H., Gürcan, Ö. D., and Hahm, T. S.

Subjects
*POTENTIAL theory (Physics), *VORTEX motion, *MAGNETIZATION, *PLASMA gases, *REYNOLDS stress, *MOMENTUM (Mechanics), *SELF-consistent field theory, *THERMOELECTRICITY, *HEAT convection
Abstract

A kinetic generalization of a Taylor identity appropriate to a strongly magnetized plasma is derived. This relation provides an explicit link between the radial mixing of a four-dimensional (4D) gyrocenter fluid and the poloidal Reynolds stress. This kinetic analog of a Taylor identity is subsequently utilized to link the turbulent transport of poloidal momentum to the mixing of potential vorticity. A quasilinear calculation of the flux of potential vorticity is carried out, yielding diffusive, turbulent equipartition, and thermoelectric convective components. Self-consistency is enforced via the quasineutrality relation, revealing that for the case of a stationary small amplitude wave population, deviations from neoclassical predictions of poloidal rotation can be closely linked to the growth/damping profiles of the underlying drift wave microturbulence. [ABSTRACT FROM AUTHOR]

Published
2010
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3. Residual parallel Reynolds stress due to turbulence intensity gradient in tokamak plasmas.

Author

Gürcan, Ö. D., Diamond, P. H., Hennequin, P., McDevitt, C. J., Garbet, X., and Bourdelle, C.

Subjects
PARALLEL algorithms, REYNOLDS stress, TURBULENCE, TOKAMAKS, PLASMA gases, SYMMETRY breaking, WAVE mechanics, MOMENTUM (Mechanics), TRANSPORT theory
Abstract

A novel mechanism for driving residual stress in tokamak plasmas based on k∥ symmetry breaking by the turbulence intensity gradient is proposed. The physics of this mechanism is explained and its connection to the wave kinetic equation and the wave-momentum flux is described. Applications to the H-mode pedestal in particular to internal transport barriers, are discussed. Also, the effect of heat transport on the momentum flux is discussed. [ABSTRACT FROM AUTHOR]

Published
2010
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