Small-scale magnetic features in active region NOAA 11024

1Kondrashova, NN, 2Leiko, UM
1Main Astronomical Observatory of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
2Astronomical Observatory of Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
Kinemat. fiz. nebesnyh tel (Online) 2019, 35(2):28-49
Start Page: Solar Physics
Language: Russian

We analyzed spectropolarimetric data obtained for an active region NOAA 11024 with the French-Italian telescope THEMIS on Tenerife (Canary Islands) on 4 July 2009, consisting of the Stokes V measurements of the photospheric lines Fe I 630.15 nm, Fe I 630.25 nm, Fe I 630.35 nm, and Ti I 630.38 nm. The region studied includes two pores of opposite polarity and two plages. One of pores was developing during observation. Eruptive events, such as chromospheric surges, Ellerman bombs were observed in this area. The Stokes V profiles of the photospheric lines vary greatly in different places in the active region. In most cases, they are normal. In pores, their amplitude increases to the outer edges of the pores. The maximal amplitude is noted for the profiles at the boundary between the emerging pore and the Ellerman bomb. It rapidly increased with time. From the analysis of the observed profiles, we have evidence for the presence of two small-scale patches with anomalous Stokes V profiles of the photospheric lines Fe I 630.15 nm and Fe I 630.25 nm in the region studied. The amplitude of the profiles in these places reduced. The amplitude and shape of the profiles changed with time. One of the patches was located between the pores, the other one in the plage area. In these patches the polarity of the photospheric magnetic field changed during the observations. Evidence of new small-scale magnetic fluxes of opposite polarity emergence is obtained. This led to the beginning of magnetic reconnections and the appearance of chromospheric surges and the Ellerman bomb. Strong oscillations of the amplitude of the Stokes V profiles of the photospheric lines Fe I 630.15 nm and Fe I 630.25 nm were found during the Ellerman bombs, which may indicate a pulsed character of energy release.

Keywords: active regions, Ellerman bombs, magnetic fields, photosphere, pores, spectro­polarimetry, Sun

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