Two-component photospheric models of a solar flare of 2N/M2 class
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| 1Andriiets, OS, 2Kondrashova, NN, 1Kurochka, EV 1Astronomical Observatory of Taras Shevchenko National University of Kyiv, Kyiv, Ukraine 2Main Astronomical Observatory of the National Academy of Sciences of Ukraine, Kyiv, Ukraine |
| Kinemat. fiz. nebesnyh tel (Online) 2014, 30(2):58-69 |
| Start Page: Solar Physics |
| Language: Russian |
Abstract: The physical state in the photosphere during the 2N/M2 solar flare on 18 July 2000 was studied. We used chelle Zeeman spectrograms obtained by Lozitsky V. G. in orthogonal circular polarizations with the solar spectrograph. Semiempirical models are derived for three times of the flare at the onset and main phases using an inversion with SIR code. Seven photospheric lines of Fe I and Cr I are used. The photosphere model has a two-component structure: a magnetic flux tube and nonmagnetic surroundings. The height dependences of the temperature, magnetic field, and line-of-sight velocity were obtained for two components. The temperature in a magnetic flux tube had some inhomogeneities with height. The layers with increased temperature were found in the middle and upper photosphere in relation to undisturbed photosphere. Temperature increase was noted at 500800 K in the lower layers during the flare. The magnetic field during the flare increased by 0.05 T in the lower and of 0.080.1 T in the upper photosphere, while its vertical gradient decreased from 0.0012 to 0.0008 T/km. The model for onset stage shows the upperflows in the lower photosphere and downflows in the upper photosphere. The line-of sight velocities significantly decreased in the main phase of the flare. The parameters of the photosphere nonmagnetic surroundings differed little from their values in the quiet photosphere. |
| Keywords: photosphere, solar flare |
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