Free Access
Astron. Astrophys. Suppl. Ser.
Volume 139, Number 1, October I 1999
Page(s) 89 - 96
Published online 15 October 1999
DOI: 10.1051/aas:1999382

Astron. Astrophys. Suppl. Ser. 139, 89-96

Analysis of evolution of NOAA 7912 active region on 19 October 1995

P. Rudawy1 - L. van Driel-Gesztelyi2,3 - B. Cader-Sroka1 - P. Mein2 - N. Mein2 - B. Schmieder2 - J.-M. Malherbe2 - B. Rompolt1

Send offprint request: P. Rudawy

1 - Astronomical Institute of the Wroclaw University, PL 51622 Wroclaw, ul Kopernika 11, Poland
2 - Observatoire de Paris, Section de Meudon, F-92195 Meudon Principal Cedex, France
3 - Konkoly Observatory, Budapest, Pf. 67, H-1525, Hungary

Received January 28; accepted June 18, 1999


An analysis of a minor (B3.2) flare related to an X-ray jet in the reversed polarity NOAA 7912 active region is presented, focusing on various kinds of activity observed in the H$\alpha$ line with the MSDP instrument. Using complementary Yohkoh soft X-ray observations and a Kitt Peak magnetic field map we study the influence of a rather low and graduate energy release on filaments, fibrils and chromospheric brightenings and their relevant coronal features. We find that this small flare affected the entire AR and was associated with strong up- and downflows along remote fibrils and filaments, which appear to be connected by large-scale loops. It is shown that at least one of the observed brightenings was caused by downflow of the matter, thus, by the kinematic heating of the material. The filament in the vicinity of the flare footpoints changed the most: it broke into two parts, temporarily rose to higher altitudes inside the AR and even erupted outside of the AR, re-forming only three hours later. We show that even a minor flare can lead to important morphological and dynamical changes in an active region.

Key words: Sun: chromosphere -- Sun: activity -- Sun: filaments

Tables at the CDS

Copyright The European Southern Observatory (ESO)

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.