Relationship of umbral dot parameters with sunspot magnetic field

Sunspots are the regions of the sun where the magnetic field is concentrated. Magnetic field controls the physical conditions in and around sunspots and produces a variety of fine structures, notably umbral dots (UDs), observed in the sunspot umbra. In this thesis study, 18 sunspot data covering the years 2013-2022 were selected from the archive data of the Goode Solar Telescope (GST) at the Big Bear Solar Observatory. The physical parameters of UDs (brightness, diameter, eccentricity, lifetime and dynamic velocity) were calculated. Although the relationship between UD parameters has been extensively studied in literature, there are only a few studies on the relationship between UD parameters and umbral magnetic field. In order to fill this gap in literature to some extent, within the scope of this thesis, relationship between the physical parameters of the UDs observed in each sunspot and umbral magnetic field was investigated. Magnetic field measurements were obtained from observations of two different instruments: GST/Near InfraRed Imaging Spectropolarimeter (NIRIS) and Solar Dynamics Observatory (SDO)/Helioseismic and Magnetic Imager (HMI). Magnetic field intensity and UD parameters were compared with two different methods (manual and automatic) and analyzed in detail, and relationship of UDs with the magnetic field was clearly revealed. Image processing techniques, particle detection and tracking algorithms, regression and Pearson correlation analysis are main methods used. As a result of the studies; i) The ranges of UD physical parameters were found to be: diameter 92.17 - 246.53 km, eccentricity 0.02 - 0.65, lifetime 0.75 - 120.00 minutes and dynamic velocity 0.01 - 3.80 km/s, ii) Intensity-diameter and diameter-eccentricity pairs showed the highest degree of correlation while lowest correlation was determined for diameter-lifetime relationships, iii) It has been concluded that as the intensity of the magnetic field increases in the sunspot umbra, the mean UD brightness observed at the same location decreases, iv) It was concluded that other calculated UD physical parameters (mean UD diameter and eccentricity) values did not show a significant relationship with magnetic field intensity at the same location in both NIRIS/HMI data.