Discrepancy between the theory and polarization observations in the 530.3 nm solar coronal line

Abstract

Results of polarization observations of the green-line corona during the eclipse of July 11, 1991, are briefly discussed. A significant discrepancy is found between the directions of polarization of the coronal green line obtained from the eclipse observations and inferred from the generally accepted theory. The observations show polarization direction in the line λ 530.3 nm to be close to that characteristic of the white-light corona; i.e., the electric vector in the scattered wave is tangential to the solar limb. This fact contradicts the theoretical conclusions (including ours) that the actual direction of the electric vector in the polarized emission of the coronal green line is radial. The cause of this drastic contradiction is not clear.