Study of the Intensity Distribution of the Green Line in the Inner Corona

Abstract

The corona is a key region of solar atmospheric activity, and the source of solar-terrestrial space weather. Limited by observation, research on the plasma structure and magnetic field state of the lower coronal atmosphere is still very lacking, and there are few international studies on the brightness stratification of the lower coronal atmosphere in the visible light band. In this paper, the coronal green line (${\text{Fe}}_{\text{XIV}}$5303 Å) observation data of Lijiang coronagraph YOGIS (Yunnan Observatories Green-line Imaging System) is used to analyze the bright structure and mid-coronal loops in the inner coronal region (1.03$R_{\odot }$–1.25$R_{\odot }$, where $R_{\odot }$ represents the solar radius) effectively. By fitting the exponential decay of the intensity of the bright structures at the radial height of the sun and comparing these fitting results, it is found that the decay index of the static inner coronal loops obtained is around a fixed value. Then, the more obvious coronal loops are extracted, and by performing the same exponential fitting on the intensities of different heights, the obtained decay index is also relatively similar to that of the bright structure, which provides a reference for further study of the evolution of physical parameters in the corona.