ISSN:
1089-7674
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The coupled nonlinear evolution of kinetic Alfvén turbulence (KAW) and anomalous alpha-particle transport is analyzed using a reduced turbulence model [Phys. Fluids B 4, 3152 (1992)]. Due to the nonlocal nature of the nonlinear interaction (bulk ion Compton scattering), the saturated spectrum consists of two well separated peaks, one in the linearly unstable and one in the stable regime. The two peaks represent the energy input from the alphas and energy dissipation to the electrons, respectively, and are in balance at saturation. Without a particle source, the turbulence-induced anomalous alpha transport leads to a flattening of the initial alpha density profile, on a time scale slow compared to the fluctuation time scale. In the presence of a particle source, a stationary alpha density profile is built up self-consistently as a result of the competition between the alpha-particle source and anomalous transport. The anomalous alpha diffusivity from the reduced model for KAW, using reactor size parameters, is found to be Danα ∼ 1 m2/s.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.870564
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