The coupled nonlinear evolution of kinetic Alfven turbulence (KAW) and
anomalous alpha-particle transport is analyzed using a reduced turbul
ence model [Phys. Fluids B 4, 3152 (1992)]. Due to the nonlocal nature
of the nonlinear interaction (bulk ion Compton scattering), the satur
ated spectrum consists of two well separated peaks, one in the linearl
y unstable and one in the stable regime. The two peaks represent the e
nergy input from the alphas and energy dissipation to the electrons, r
espectively, and are in balance at saturation. Without a particle sour
ce, the turbulence-induced anomalous alpha transport leads to a flatte
ning of the initial alpha density profile, on a time scale slow compar
ed 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 anom
alous transport. The anomalous alpha diffusivity from the reduced mode
l for KAW, using reactor size parameters, is found to be D(alpha)an ap
proximately 1 m2/s.