Studies Of Bright Points In Lower Solar Atmosphere

There are two parts of work included in this thesis.In the first one,we developed a novel method of identifying and tracking both the isolated and the non-isolated BPs in the photosphere.The isolated(non-isolated)BPs are those that did not(did)experience either splitting or merging in their lifetimes.With the new method,we totally identified 2010 BPs.Among them 35% are non-isolated,and the rest are isolated.We mainly studied basic properties(such as the lifetime,area and intensity)of the isolated and the non-isolated BPs in different background magnetic field regions.The results show that the area and intensity of both the isolated and the non-isolated BPs are independent of the background magnetic field.However,the lifetime are shorter in the regions of stronger background magnetic field and are longer in the regions of weaker background magnetic field.The number density and area coverage of BPs are higher in the stronger background magnetic field regions than those in the weaker background magnetic field regions.Based on the first work,we further developed a method of identifying and tracking both the photospheric bright points(PBPs)and the chromospheric bright points(CBPs),as well as pairing them.We identified,tracked and paired 278 BPs.And then,we found that the lifetimes of PBPs and CBPs are positively correlated with a coefficient of 0.8.We further analyzed the difference in appearance time,disappearance time,and lifetime of these BP pairs.These three parameters all follow the Gaussian distribution.We conclude here that the formation and disintegration mechanisms of PBPs and CBPs might be different.However,both the formation and disintegration of PBPs and CBPs are based on the formation and disintegration of flux tubes they are located in.Therefore,this is probably the reason that lifetimes of the PBP and the CBP have positive correlation with each other.We further calculated the horizontal displacement between the PBP and the CBP at the same observation time.The displacements follow Gaussian distribution.We also calculated the perturbation displacement of the flux tubes and found that it follows exponential distribution.Such perturbation displacement might be caused by the propagation of the MHD waves along the flux tubes.