Doppler and proper motions accompanying formation of an additional magnetic flux in the mature solar active region (NOAA 7216)

¹ Astronomical Institute, Academy of Sciences of the Czech Republic, 251 65 Ondřejov, Czech Republic
² Heliophysical Observatory of the Hungarian Academy of Sciences, H-4010 Debrecen, P.O. Box 30, Hungary

Send offprint request to: V. Bumba

Received: 31 October 1995
Accepted: 18 December 1995

Abstract

We document the evolution of an additional magnetic flux in the photosphere of a fully developed sunspot group, we measure longitudinal magnetic field, line-of-sight motions, and proper motions of sunspots in the group during this process. We demonstrate the close correlation of magnetic field, Doppler and proper motion singularities with the area in which additional magnetic flux appears and the new penumbrae and umbrae develop. We discuss the probable reasons for this fact and for the region's weak flare activity. There exist in the group about eight sunspots with the Evershed effect, differing in form, in dependence on the history of development of the spot in which it is observed.