CAOSP abstracts, Volume: 35, No.: 3, year: 2005

Abstract: Spectral Variation Analysis (SVAN) was applied to our own database of Coronal Green Line Brightness (CGLB) covering almost six solar cycles (1939-2001) to investigate differential rotation of the solar corona. Detailed knowledge of solar rotation seems to be crucial for a better understanding of the basic mechanisms of solar activity generation. The following principal results were obtained: (a) The synodic period of coronal rotation increases from 27 days at the equator to about 29 days at the latitudes of ± 40°, displaying the less pronounced differentiality than the photospheric phenomena do. (b) Above ∼ ± 45° differentiality greatly diminishes and the rotation displays actually rigid character (with the period of about 29.5 days) up to polar regions. (c) The total corona rotation may be expressed as a sum of two modes, the faster one with period of 27 days (slightly increasing towards the higher latitudes), and the slow one with the period of about 30.5 days; the relative contribution of these modes to the total rotation rate is estimated in dependence on latitude. A short comment on relation of our findings with the latest achievements of helioseismology is given.