Breno Raphaldini

Magnetic helicity is a measure of the entanglement of magnetic field lines, which is commonly used to characterize the complexity of magnetic field structures in solar active regions. Previous attempts to use helicity based indicators to predict solar eruptive/flaring events have not been universally successful, suggesting that extra information is necessary to determine in advance whether an active region will exhibit such events. Here we investigate the use of a quantity associated with the magnetic helicity, the magnetic winding, which represents a the fundamental entanglement of the magnetic field lines, but which is independent of the field's strength (unlike the helicity). We use vector magnetogram data derived from HMI images to calculate the evolution and distribution of the magnetic winding associated with four different active regions, two of them with small flaring activity/non-flaring AR 11318, AR 12119, and the other two highly active with X-class flares AR 11158, AR 12673. Our aim is to compare the evolution of these active regions in terms of their magnetic winding and helicity evolution. We decomposed the field data into their potential and current carrying components and calculated their respective mean net winding time series and distributions. It is shown that the active regions which show flaring/eruptive activity have significant contributions to the winding input from the current carrying part of the field, while the winding of active region that has no eruptive events is dominated by its potential component. A significant and rapid input of current carrying winding is found to be a precursor of flaring/eruptive activity, and in conjunction with the helicity sharp inputs of both quantities are found to precede individual flaring events by approximately 20 hours. This suggest that strong input of topologically complex current carrying field is an important element for the ignition of heavy flaring active region.