A helicity proxy from horizontal solar flow patterns

Motivated by new observations of solar surface how patterns of mesogranulat ion, theoretical computations of the horizontal divergence-vorticity correl ation are presented. Because of its close relation to the helicity in rotat ing turbulence such observations and discussions are of particular importan ce for the conventional dynamo theory. For the northern hemisphere we find a small, but always negative, divergence-vorticity correlation. Both an ana lytical Second Order Correlation Approximation for slow rotation as well as a numerical simulation (originally done for accretion disks) for fast rota tion yield very similar results.