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Solar photosphere under an eruptive filament
Wollmann, Jiří ; Švanda, Michal (advisor) ; Zemanová, Alena (referee)
Filaments are enlongated structures of plasma in solar atmosphere held by solar magnetic field. The aim of this thesis is to study the photosphere near the eruptive filament. An eruptive filament is a filament that erupts in the final stage of its life. The studied filament was located at 10◦ of heliographic longiitude close to the central meridian on October 21 2010. The measurements of the vector velocity fields with a cadence of 6 hours were analysed, as well as the observations in the Hα line with a cadence of 1 min and the maps of the line-of-sight component of the magnetic field with a cadence of 45 s. From the Hα measurements first the evolution of the filament was studied, including the phase of its activation and eruption. Then the 6-hour averages were studied and mutually compared. The velocity field was used to study the flows in the vicinity of the filament. It was found that before the phase of activation convergent flows towards the spine of the filament was enhanced, which disappeared after the filament eruption. From the magnetograms the potential-approximation magnetic field in the region of the filament was also computed and its evolution was studied. 1
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Spectral analysis of flares on AD Leo
Wollmann, Jiří ; Heinzel, Petr (advisor) ; Korčáková, Daniela (referee)
Solar flare is a process which releases magnetic energy stored in the solar corona due to the effect of magnetic reconnection. Similar activity has been observed on other stellar types, namely type K and M stars, which usually have vast and strong magnetic field. Often during flares on M stars we observe asymmetry of profiles of some spectral lines with enhanced red wing. The cause of these asymmetries is not well understood. The aim of this thesis is to analyse spectra of AD Leo, which is frequently flaring dMe star, and to model radiation of the Hα line coming from flare loops analogically to flare loops on the Sun. The light curves of selected spectral lines rise sharply during initial phases of flares and gradually fall back to preflare state. The light curves of continua surrounding these selected spectral lines rise sharply in the blue part of the spectrum during flares. The continua in the red part exhibit only small rise. Simulations of Hα radiation coming from flare loops yield asymmetric profiles with highly enhanced red wings. 1
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Solar photosphere under an eruptive filament
Wollmann, Jiří ; Švanda, Michal (advisor) ; Zemanová, Alena (referee)
Filaments are enlongated structures of plasma in solar atmosphere held by solar magnetic field. The aim of this thesis is to study the photosphere near the eruptive filament. An eruptive filament is a filament that erupts in the final stage of its life. The studied filament was located at 10◦ of heliographic longiitude close to the central meridian on October 21 2010. The measurements of the vector velocity fields with a cadence of 6 hours were analysed, as well as the observations in the Hα line with a cadence of 1 min and the maps of the line-of-sight component of the magnetic field with a cadence of 45 s. From the Hα measurements first the evolution of the filament was studied, including the phase of its activation and eruption. Then the 6-hour averages were studied and mutually compared. The velocity field was used to study the flows in the vicinity of the filament. It was found that before the phase of activation convergent flows towards the spine of the filament was enhanced, which disappeared after the filament eruption. From the magnetograms the potential-approximation magnetic field in the region of the filament was also computed and its evolution was studied. 1
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