Spectral study of Ellerman bombs. The photosphere

Heading: 
1Pasechnik, MN
1Main Astronomical Observatory of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
Kinemat. fiz. nebesnyh tel (Online) 2018, 34(2):25-45
https://doi.org/10.15407/kfnt2018.02.025
Start Page: Solar Physics
Language: Russian
Abstract: 

The results of the spectral observation analysis of two Ellerman bombs (EB-1 and EB-2), which were formed and have evolved in the emerging magnetic flux area of active region NOAA 11024, are presented. The spectral data with high spatial and temporal resolution (about 3 seconds) were obtained with the French-Italian solar telescope THEMIS on July 4, 2009. The observation time was 20 minutes. We used a spectral region of 630 nm, which included four Fraunhofer lines that are formed over a wide range of photospheric heights: the neutral iron lines Fe I λ 630.15 nm, 630.25 nm, 630.35 nm and the titanium line Ti I λ 630.38 nm. During our observations, the brightness of EB-1 decreased, and brightness EB-2 increased. The metal line profiles obtained for different periods of the EBs development were asymmetric. Asymmetry was more pronounced in weak lines, the profiles of which consisted of several components in most cases. It was found that when the central depth of the profiles decreases, their half-width increased. Changes of the Fraunhofer lines central intensity in the spectra of the Ellerman bombs and their vicinity at different stages of the EBs evolution were analyzed. EBs developed in the intergranular lanes. An increase the core intensity of all the photospheric lines, used in the work, spatially correlated with an increase of the intensity in the Hα line wings. At all photospheric levels, the brightness changes were of an oscillatory nature, the interval between the vibrations was 1 to 5 minutes. The temporal changes of the Fraunhofer line intensities in the spectra of the AO region under investigation indicate that as a result of the emergence of the new magnetic flux, there have been consecutive magnetic reconnections in the EB-1 region, the excitation has propagated along the magnetic loop and caused the appearance of the EB-2, then they developed as a physically connected pair.

Keywords: activity, Ellerman bombs, photosphere, spectral study, the Sun
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