Detailed analysis of flares, magnetic fields and activity in the sunspot group of Sept. 13-26, 1963

Harold Zirin, Susan Werner

Research output: Contribution to journalArticlepeer-review


We analyze large-scale H-alpha movies of the large spot group of Sept. 13-26, 1963, together with radio, ionospheric and magnetic field data as well as white light pictures. The evolution of the group and associated magnetic fields is followed, and the positions of solar flares relative to the fields are noted, along with their morphology. Although the magnetic field is deformed in time, characteristic field structures may be traced through the deformation as the seat of recurrent homologous flares. We find that most flares are homologous, and some are triggered by disturbances elsewhere in the region. We note events produced by surges falling back to the surface, and one flare initiated by a bright bead seen to fly across the region. In almost every case of an isolated type III radio burst, a corresponding H-alpha brightening could be found, but not all flares produced bursts. Flares close to the sunspots are most likely to produce radio bursts. Flare surface waves in the region all travel out to the west, because of more open magnetic field structure there. In one case (Sept. 25) a wave is turned back by the closed field structure to the east. In almost all cases the time association of radio or ionospheric events is with the beginning of the flare or with the flash phase. Several morphological classes of flares are noted as recurrent types.

Original languageEnglish (US)
Pages (from-to)66-100
Number of pages35
JournalSolar Physics
Issue number1
StatePublished - Jan 1967
Externally publishedYes

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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