New method for separating K- and F-corona brightness based on LASCO/SOHO data

Abstract

A relatively simple (in technology) method for separating K- and F-corona brightness based on LASCO data, which makes it possible to obtain the latitude distribution of this brightness in the field of view of the LASCO C2 and C3 coronographs at any instant for which white light corona images are available, has been proposed. It has been estimated that the error in determining K-corona brightness varies from 20 to 50% at distances of R ≤ 6R_⊙ (R_⊙ is the solar radius). At distances of R > (5–6)R_⊙, the accuracy of the K-corona brightness determination decreases and is of an estimative character. Nevertheless, it is often possible to trace the brightest coronal rays and the K-corona regions of decreased brightness (including such regions in coronal holes) to distances of R ≈ 15R_⊙ and 25–30R_⊙ for some events. This makes it possible to estimate and compare electron densities in different coronal structures to large distances. Examples of method testing are presented. For the first time, we have managed to obtain continuous (in latitude) distributions of K- and F-corona brightness, using this method.