The focus of this thesis is to investigate magnetic reconnection in the solar chromosphere by usinghigh spatial resolution data including polarimetric signals. Magnetic reconnection occurs whenmagnetic field lines of different directions come in contact and change the configuration of the fieldlines. When this happens in the solar atmosphere, magnetic energy is transformed into thermalenergy (heating) and kinetic energy. This is observed as brightenings and fast plasma motions. The data was taken with the Swedish 1-m Solar Telescope (SST) on La Palma (Spain) in 2016 andincludes the spectral lines CaIIK, CaII8542 Å , FeI6301/6302 Å and Hα. The observations ofCaII8542 Å and FeI6301/6302 Å also include polarimetric signals. The analysis is done by inferringthe atmospheric conditions in which the events are evolving with the inversion code STiC using thefirst three lines mentioned. Before the inversion, several methods were used to improve the datasuch as denoising using a convolution neural network. The improvements were done to enhancethe polarimetric signals of Stokes Q and U. These signals are usually hard to detect since thepolarization signal is smaller by a factor 10^3-10^4 than the observed intensity. In this thesis, two reconnection events were studied in detail. The first event was identified as anEllerman bomb type event. We detect a compact, smaller than 12, enhancement in the temperatureand bidirectional flow of plasma where two magnetic concentrations of opposite polarities came incontact. The second event is identified as a light-bridge jet type event where the vertical magneticfield of a pore is interacting with the horizontal magnetic field of a light bridge. It is characterized bystrong fan-shaped jets, high-velocity plasma flows, and an elongated temperature enhancement.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:su-202479 |
| Date | January 2020 |
| Creators | Koskelainen, Filippa |
| Publisher | Stockholms universitet, Institutionen för astronomi |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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