Authors: Mausumi Dikpati (NSF-NCAR, HAO)

Flux emergence is often described as magnetic tubes rising through the convection zone, but the central unresolved issue is whether the Sun actually delivers active regions as coherent deep-rooted tubes, as thick distorted magnetic bands, or as flux systems that are only finally assembled near the surface. The purpose of this scene-setting talk is to involve the audience for a constructive debate on the following unsettled questions: (a) Where does active-region flux originate? Do active regions emerge from deep-seated dynamo fields or form through near-surface magnetic self-organization? (b) Are active regions produced by thin flux tubes, thick magnetic bands, or distributed magnetic systems? (c) Is flux emergence governed by a single physical process throughout the convection zone, or does the dominant physics change with depth as magnetic flux approaches the solar surface? (d) What physical processes transform subsurface magnetic flux into coherent sunspots and magnetically complex active regions? (e) Can observable or model-based precursors reliably forecast active-region emergence, and what can the properties of newly emerged active regions tell us about their rise times and subsurface origins?