Kirill Kuzanyan (Russian Academy of Sciences, National Astronomical Observatory of Chinese Academy of Sciences): Helicity and Twist of Solar Magnetic Fields: an Intrinsic Property of the Dynamo Mechanism.
Solar Magnetism known for its 11-year cyclicity is driven by the shear, internal differential rotation in the solar convection zone, and the breakage of mirror-symmetry of turbulent convective motion (kinetic and magnetic helicity). The origin of helicity comes from background turbulent dynamo action as well as large-scale tilt of bipolar magnetic flux tubes, the building material for sunspots. We carry out quantitative computations of the amounts of helicity in bipolar solar active regions produced by tilting the flux tubes and compare with those produced by the global dynamo. We obtain that these amounts are comparable by the order of magnitude though opposite in sign. We conclude that in smaller active regions the dynamo-born helicity dominate its tilt-related part. The amount of helicity residing in the solar photosphere (that can be observed from available magnetographic data) can be considered as the remainder from the amounts of helicity produced and those leaving the Sun with CMEs and solar wind.
We give observational interpretation and support of the results.