The Color of Solar Corona Structures

Abstract

Two-dimensional distributions of the relative color index (RCI) of the continuous corona spectrum of 1991 and 2006 reveal that the energy distributions in the continuums of the corona and photosphere differ, as do the RCI values for different coronal structures. The approximate symmetry of RCI distributions relative to the HCS projection on the sky plane excludes the contribution of the dust component. The revealed reddening with distance over the entire corona at all position angles is explained by the propagation of electron fluxes in the entire corona volume. It is noted that scattering by bound ion electrons causes bluing at distances of <1.3 R☉. Thus, studies of coronal color give information about the dynamics of the electron component of the coronal plasma and the composition of the coronal matter.