Solar active regions (ARs – sunspot groups and associated phenomena) are formed by the emergence of magnetic flux bundles from the Sun’s interior into its atmosphere. The outcome of this emergence process through the turbulent medium of the solar convective zone is subject to very significant random fluctuations, so active regions often strongly deviate for the idealized simple bipolar structure, oriented East-West with a slight latitude dependent tilt. Unusual structure and/or size of an AR may, in turn, result in a large deviation of the amplitude of the global dipole magnetic field built up from the remains of ARs which serves as a seed field for the next 11-year solar magnetic cycle, hence it can give rise to major intercycle variations in the level of solar activity and other cycle properties.

The purpose of the team was to discuss and further study the factors that determine what makes such an exceptional or rogue AR, i.e. what properties of an AR determine its dynamo effectivity. The importance of this issue lies in its key role for our ability to predict an upcoming solar cycle and thereby to provide reliable space climate forecasts on a time scale of years to decades. Developing a capability to forecast space climate variations is important for the planning of future space missions.