Lithium as a passive tracer probing the rotating solar tachocline turbulence

The rotational influence on the eddy-diffusivity tensor D-ij for anisotropi c turbulence fields is considered in order to explain the lithium decay law during the spin-down process of solar-type stars. Rotation proves to be hi ghly effective in the transfer of chemicals through the solar tachocline (b eneath the convection zone) which is assumed to contain only turbulence wit h horizontal motions. The effect is so strong that the tachocline turbulenc e must not exceed a limit of similar to 10(-(3...4)) of the rms velocity in the convection zone in order to let the lithium survive after Gigayears. S uch long depletion times can also be explained by a very small rotational i nfluence upon the eddy-diffusion tensor if it is realized with correlation times shorter than 15 min. It is argued that such slow and/or short-living turbulence beneath the convection zone could hardly drive the solar dynamo. In our theory the diffusion remains small for rapid rotation due to the ro tational quenching of the turbulence. In young stellar clusters like Pleiad es, there should be a (positive) correlation between rotation rate and lith ium abundance, where the fastest stars should have maximal lithium. First i nspections of the data seem to confirm this finding.