Determine the appropriate subsurface sunspot model

Determine whether the monolithic model or the cluster model more appropriately describes the subsurface magnetic structure of sunspots, thereby resolving the competing interpretations of the invisible deeper layers.

Background

Sunspots have strong magnetic fields and complex subsurface structures that cannot be directly observed because the deeper solar layers become opaque. Two principal models have been proposed: the monolithic model, which describes a single coherent magnetic structure, and the cluster model, which describes a bundle of smaller flux tubes.

Although local helioseismology provides indirect constraints and recent results appear to favor the cluster model, the available observations and their interpretations remain insufficient to establish conclusively which model is correct.