Influence of Random Fluctuations in the Λ‐Effect on Meridional Flow and Differential Rotation

We present a mean field model based on the approach taken by Rempel(astro-ph/0604451) in order to investigate the influence of stochasticfluctuations in the Reynolds stresses on meridional flow and differentialrotation. The stochastic fluctuations found in the meridional flow patterndirectly resemble the stochastic fluctuations of the Reynolds stresses, whilethe stochastic fluctuations in the differential rotation are smaller by almosttwo orders of magnitude. It is further found that the correlation length andtime scale of the stochastic fluctuations have only a weak influence onmeridional flow, but a significant influence on the magnitude of variations inthe differential rotation. We analyze the energy fluxes within the model toestimate time scales for the replenishment of differential rotation andmeridional flow. We find that the time scale for the replenishment ofdifferential rotation (~10 years) is nearly four orders of magnitude longerthan the time scale for the replenishment of meridional flow, which explainsthe differences in the response to stochastic fluctuations of the Reynoldsstress found for both flow fields.Comment: 7 pages, 4 figure