What helioseismology teaches us about the Sun

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5 Scopus citations

Abstract

Helioseismology uses observations of oscillations of the solar surface to determine the internal structure and dynamics of the Sun, providing critical knowledge about the mechanisms of solar variability and activity cycles. The recent advances based on observations from SOHO spacecraft and GONG network have allowed us to study both long-term changes of the global structure and circulation and short-term variations associated with developing active regions, sunspots and coronal activity. In particular, the global helioseismology results have revealed 1.3-year variations of the rotation rate in the tachocline, but found no indication of 11-year variations. Studies of the meridional circulation have shown formation of additional meridional cells of flows converging toward the activity belts, thus, questioning the flux-transport theories of the solar cycle. It is found that sunspots as cool objects appear to be only 4-5 Mm deep, but accumulate significant heat in the deeper layers, and also form converging downflows. Large active regions are formed as a result of multiple flux emergence, and no evidence of large-scale emerging Ω-loop has been found. This paper presents a brief review of these and some other results of helioseismology, analysis techniques, and perspectives.

Original languageEnglish (US)
Pages (from-to)795-806
Number of pages12
JournalEuropean Space Agency, (Special Publication) ESA SP
Issue number535
StatePublished - Oct 20 2003
Externally publishedYes
EventProceedings of the ISCS 2003; Solar Variability as an Input to the Earth's Environment - Tatranska Lomnica, Czech Republic
Duration: Jun 23 2003Jun 28 2003

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering
  • Space and Planetary Science

Keywords

  • Active regions
  • Differential rotation
  • Global circulation
  • Helioseismology
  • Solar radius
  • Subphotospheric velocity field; magnetic reconnection
  • Synoptic maps

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