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Solar Physics

, Volume 160, Issue 1, pp 133–149 | Cite as

Noise storms and the structure of microwave emission of solar active regions

  • V. M. Bogod
  • V. Garimov
  • G. B. Gelfreikh
  • K. R. Lang
  • R. F. Willson
  • J. N. Kile
Article

Abstract

Solar radio and microwave sources were observed with the Very Large Array (VLA) and the RATAN-600, providing high spatial resolution at 91 cm (VLA) and detailed spectral and polarization data at microwave wavelengths (1.7 to 20 cm - RATAN). The radio observations have been compared with images from the Soft X-ray Telescope (SXT) aboard theYohkoh satellite and with full-disk phoptospheric magnetic field data from the Kislovodsk Station of the Pulkovo Observatory. The VLA observations at 91 cm show fluctuating nonthermal noise storm sources in the middle corona. The active regions that were responsible for the noise storms generally had weaker microwave emission, fainter thermal soft X-ray emission, as well as less intense coronal magnetic fields than those associated with other active regions on the solar disk. The noise storms did, however, originate in active regions whose magnetic fields and radiation properties were evolving on timescales of days or less. We interpret these noise storms in terms of accelerated particles trapped in radiation belts above or near active regions, forming a decimetric coronal halo. The particles trapped in the radiation belts may be the source of other forms of nonthermal radio emission, while also providing a reservoir from which energetic particles may drain down into lower-lying magnetic structures.

Keywords

Radiation Belt Microwave Emission Coronal Magnetic Field Solar Active Region Magnetic Field Data 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Kluwer Academic Publishers 1995

Authors and Affiliations

  • V. M. Bogod
    • 1
  • V. Garimov
    • 1
  • G. B. Gelfreikh
    • 1
  • K. R. Lang
    • 2
  • R. F. Willson
    • 2
  • J. N. Kile
    • 2
  1. 1.Special Astrophysical Observatory RASSt. PetersburgRussia
  2. 2.Department of Physics and AstronomyTufts UniversityMedfordUSA

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