fl226.gan01 Posted: 17-Jan-96 Updated: 26-Apr-96 Events specified:
Gan,W.Q., Watanabe,T., and et al.
We scanned all over four years' Yohkoh data and picked out such events that they have a ralatively complete time history in BCS observations, and they show to be single loop structure or single loop dominated structure in SXT images. With this judgement, we obtained totally around 200 samples. As a first step of the work, we plan to make a simple statistical analysis on the data, and try to provide a supplementary to the known conclusions. Then we will discuss specially the redshifted events and try to make a comprehensive conclusion. We plan also to study in a little detail some events which show to have a great line blue shift. The last stage of this work is to explain the data by constructing hydrodynamical models.
Events used: about 200 events, which satisfy the judgement mentioned above.
Specially interesting events: 22-Apr-93 14:08UT;
18-Mar-93 21:10UT;
16-Dec-91 22:04UT; and so on
Update 26-Apr-96
The following paper has been submitted to ApJ.
A STATISTICAL STUDY FOR THE RESONANCE LINE OF CaXIX OBSERVED WITH YOHKOH BRAGG CRYSTAL SPECTROMETER W. Q. GAN Purple Mountain Observatory, Nanjing 210008, China T. WATANABE National Astronomical Observatory, Mitaka, Tokyo 181, Japan
ABSTRACT
Using the observational data of Bragg crystal spectromater on Yohkoh for the period from October, 1991 to the end of 1995, we have made a statistical study for the flares which show to be in a single loop or a single loop dominated in the SXT images. Totally 158 flares are sampled. Under the temporal resolution of three seconds, we conclude that although the blue asymmetry is very common during the impulsive phase, the number of events with total blueshift is rather small, especially the number of events with great total blueshift is very small, unlike the predictions of some hydrodynamic models. It is also found that the blueshift for most flares appears at the early impulsive phase and is temporally correlated with the broadening of the line. These results demonstrate the necessarity to check the universality of chromospheric evaporation in solar flares.