Helioseismic signature of fragmentation of magnetic flux beneath sunspot photosphere?

Broock, Elena; Donea, Alina; Martinez-Cifuentes, Angel; Lindsey, Charles
Bibliographical reference

SDO 2025 Science Workshop: A Gathering of the Helio-hive! Online at <A HREF="https://sdo2025.sdo-workshops.org/">https://sdo2025.sdo-workshops.org/<…

Advertised on:
2
2025
Number of authors
4
IAC number of authors
1
Citations
0
Refereed citations
0
Description
A crucial element of the stability of sunspots was the apparent need for the umbral magnetic flux, monolithically dense in the photosphere, to separate into thin magnetic strands a few hundred km beneath its photosphere (Eugene Parker, 1979). The submerged medium separating the magnetic strands bears a crucial relationship to umbral dots, which admit most of the thermal energy flux that penetrates into the umbral photosphere. Subjacent-vantage phase-correlation acoustic holography by Brooke et al. (2025) shows signatures of "strong acoustic scatterers" in the extreme outer convection zone beneath the sunspot photosphere. They propose that these features are a signature of Parker's proposed fragmentation of the magnetic flux in the shallow sunspot sub photosphere. An understanding of the implications of these helioseismic signatures could help us penetrate a diverse array of outstanding fundamental problems in sunspot structure and dynamics. It may lead us, for example, to a recognition of the reservoir into which the convective flux blocked by inhibited convection is diverted by a sunspot during its sometimes weeks-long life cycle.