Variations of the CaI λ6102.7 Å line profile and the magnetic field structure during the solar flare of August 12, 1981

  • А.Н. Бабин Crimean Astrophysical Observatory, Nauchny, Crimea, Ukraine, 98409
  • А.Н. Коваль Crimean Astrophysical Observatory, Nauchny, Crimea, Ukraine, 98409

Abstract

We present results of the study of changes of the CaI λ6102.7 Å line profiles and the magnetic field structure during the 1B/M2.2 white light flare of August 12, 1981. Two brightest flare knots located in the penumbra of the sunspot with δ-configuration have been investigated. IБV profiles of spectral lines were analyzed. We have found that: 1) the significant changes of the line profiles take place during the flare especially at the time of white light flare emission that was observed close to the maximum of the Hα flare development. The line depth reduces substantially and narrow Zeeman-split emission with the longitudinal field strength up to 3600 Gs are detected. It is stronger than that derived from the absorption lines in the sunspot below the emission; 2) the most significant observed variations of the CaI λ6102.7 Å line profile during the flare can lead to the underestimate of measured longitudinal magnetic field strength with a videomagnetograph up to 4.5 times, but cannot lead to the polarity reversal; 3) the sharp short duration displacement of the neutral line, occurred close to the flare Hα maximum leads to the appearance of the area of inverted polarity field, that is the magnetic field transient. This may be interpreted as a change of the force tubes inclination during the flare. Simultaneously observed depolarization of the CaI λ6102.7 Å line radiation may be the result of changes of the magnetic field structure too; 4) this fast dynamical changes of the magnetic field lines took place after the impulsive phase maximum and were close to the appearance of the II type radio emission.

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Published
2008-12-26
How to Cite
Бабин А., Коваль А., 2008. Izvestiya Krymskoi Astrofizicheskoi Observatorii, vol. 104, no. 1, pp. 19-29. Available at: https://jn.craocrimea.ru/index.php/izvcrao/article/view/587 (Accessed: 4December2020)
Section
Research articles