Solar Helicities in Theory and Observations: Implications for Space Weather and Dynamo Theory

Magnetic helicity is a conserved quantity in ideal MHD and is also a topological invariant. Due to these properties, it plays special roles for the operation of the global solar dynamo, and in the release of solar eruptive events, but both of these related processes remain poorly understood. On both themes, theoretical models would benefit from being validated and constrained with observational data, and the increasing amounts of observational data could be more efficiently used as basis to improve the models. The abundant observational data pouring in from various sources poses its own challenges and sometimes cross-calibrations are lacking. This program will bring together solar observers and dynamo theorists to work on these topics. We aim to obtain crucial new knowledge on the operation of the global solar dynamo itself, but also how it drives eruptive events which then are observed as space weather.