Magnetic and current helicities in solar dynamos Original Research Article

Current helicity data for solar active region provide the unique observational information for so-called α-effect which plays a key role in astrophysical dynamos producing large-scale magnetic fields of celestial bodies. We discuss problems arising in comparison between helicity data and predictions of solar dynamo theory. In particular, a significant excess of active regions with the “wrong” sign of helicity is seen to occur just at the beginning of the 11-year solar cycle. We attribute the excess partially to additional current helicity production from the twisting of rising magnetic flux tubes. We demonstrate that the excess is much less pronounced in the twist data. Future perspectives of helicity observations are discussed.