22-years magnetic cycle in polar activity of the Sun
Abstract
We have digitized and processed the daily K-CaII-line full disk spectroheliograms from the archive of the Kodaikanal Observatory during 1907-1995. The programm has been worked out to determine the boundaries of the bright areas (plages, decayed plages, enhanced network features, K-CaII bright points and so on) with contrast that exceeded a level of the quiet Sun on the given value. About the 1.2 {times} 10^6 K-CaII active regions of different scales were processed. The coordinates, areas, the tilt and latitude-time distributions of bright features were determined. At the high latitudes the K-CaII bright points form a polar branch of solar activity at the period between the polar magnetic field reversals. This polar activity shows both 11-year's and 22-year's cycles. We found that the polar K-CaII bright point cycles proceed on average 5.5 years the sunspot cycles.
- Publication:
-
Multi-Wavelength Investigations of Solar Activity
- Pub Date:
- 2004
- DOI:
- 10.1017/S1743921304005368
- Bibcode:
- 2004IAUS..223..125M