Helioseismic observations of subphotospheric dynamics of sunspots and developing active regions

A. G. Kosovichev, T. L. Duvall, Junwei Zhao

Research output: Contribution to journalConference articlepeer-review

2 Scopus citations


New methods of time-distance helioseismology provide us unique information about the structure and dynamics of sunspots and active regions in the upper convection zone. We present three-dimensional maps of the sound-speed perturbations and flow velocities obtained from the SOHO/MDI data for sunspots, emerging flux events and evolving active regions. The results reveal complex dynamics of magnetic structures below the solar surface, and shed light on the mechanisms of sunspots and active regions, and magnetic field dynamics. One interesting case that includes a fast spinning sunspot accompanied with subphotospheric vortex motions and twisting coronal loops represents an intriguing example of magnetic coupling between the subphotospheric processes and the atmospheric activity. The evolution of a large active region, NOAA 9393, has been studied for almost 3 solar rotations in March-April 2001, including the periods of emergence, maximum activity and decay. It is concluded that this active region was formed by fragmented magnetic flux tubes emerging during an extended period of time rather than by a single large Ωloop broken into smaller flux tubes near the surface.

Original languageEnglish (US)
Pages (from-to)79-82
Number of pages4
JournalEuropean Space Agency, (Special Publication) ESA SP
Issue number505
StatePublished - Oct 2002
Externally publishedYes
EventProceedings of the Magnetic Coupling of the solar Atmosphere Euroconference and IAU Colloquium 188 - Santorini, Greece
Duration: Jun 11 2002Jun 15 2002

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering
  • Space and Planetary Science


  • Helioseismology
  • Solar activity
  • Solar cycle
  • Solar interior
  • Sunspots


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