Pre-flare changes of the solar photosphere using THEMIS observations data
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| 1Andriiets, OS, 2Kondrashova, NN 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(1):50-60 |
| Start Page: Solar Physics |
| Language: Russian |
Abstract: The physical state of the photosphere 1 hour 50 min before the C1-class solar flare on 24 May 2012 was studied. We used some data of the spectropolarimetric observations with the telescope THEMIS (Tenerife, Spain). Semiempirical models were derived from the inversion with SIR code, described by Ruiz Cobo and del Toro Iniesta [Ruiz Cobo, del Toro Iniesta, Astrophys. J., 1992, 398]. Nine semiempirical models of solar photosphere were constructed. Each photospheriс 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. According to the models, the parameters of the magnetic field and the thermodynamical parameters changed strongly before the flare during 8 minutes of the observations. The models contain the layers with increased and decreased temperature. The magnetic field strength in the models varied from 0.2 T in the lower photospheric layers to 0.13 T in the upper ones. Line-of-sight velocities in the lower and middle layers of the photosphere did not exceed 2 km/s, and were up to 5-6 km/s in the upper ones. Some differences in the physical state of the photosphere and its changes are revealed for different places of the active region before the flare. |
| Keywords: photosphere, Sun, THEMIS |
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