Morphology of solar filaments during the solar maximum of cycle 24: A study of 35 filaments focusing on chirality, barb orientation, skewness, and eruptive behavior

Abstract

Filaments in the solar atmosphere are plasma structures held aloft by magnetic fields, counteracting the pull of gravity. Analyzing their magnetic structure is challenging due to the lack of direct observations of their magnetic fields. However, through multiwavelength intensity observations, one can infer their morphology. We identified 35 solar filaments during the maximum period of solar cycle 24. In order to ascertain their chirality, we analyzed Hα intensity observations. Using coronal ultraviolet intensity images, we also determined the skewness of the related coronal arcades. Furthermore, based on adjacent active regions, we classified filaments as quiescent or active according to the strength of nearby photospheric magnetic fields. We followed every filament over time to estimate their characteristics. The hemispheric chirality preference is followed by 27 (77%) filaments across all categories, based on observed bearing sense. We examined the skewness of the coronal arcades connected to 19 filaments, and they all complied with the hemisphere helicity criterion. The morphology of 16 filaments was also ascertained by integrating the skewness and bearing sense. There were 2 filaments with a sheared arcade morphology and 14 with a flux rope shape. Additionally, by analyzing the changes in the skewness of coronal arcades and the bearing sense of filament barbs over time, we examined the variation in the filament's magnetic structure. Further, we examined the temporal evolution of selected filaments that exhibit peculiar characteristics during the observational period. Lastly, we investigated the eruptive characteristics of these filaments. We did not find filaments that are more likely to explode because they do not adhere to the hemispheric chirality preference.