Helicity patterns on the sun Original Research Article

Solar magnetic fields exhibit hemispheric preference for negative (positive) helicity in northern (southern) hemisphere. The hemispheric helicity rule, however, is not very strong, — the patterns of mixed helicity were observed at different spatial scales in each hemisphere. Helicity patterns on scales larger than the size of typical active region were observed in distribution of active regions with abnormal (for a give hemisphere) helicity, in large-scale photospheric magnetic fields and coronal flux systems. We review the observations of large-scale patterns of helicity in solar atmosphere and their possible relationship with (sub-)photospheric processes.