Solar flares with short and long decay components

Science Nugget Nov 21, 1997

    We supported the SERTS 1997 flight on 18 November 1997 by keeping the data between 19:37 and 19:57 UT from being overwritten. The following picture is an SXT full-disk image around the time of the SERTS launch. The box shows the field of view of SXT partial frame images (220000 km square). (Click on the picture to see a larger, more visible, version.)
    In the following, SXT partial frame images are displayed. In order to disentangle the line of sight differential emission measure, we ran a four-filter sequence. Note that this active region, AR 8108, shows us even in the thickest (Beryllium) filter. The field of view is 220000 km square.


    AR 8108 produced a number of C class flares. One of them was on 17 November 1997 at 15 UT. Although its soft X-ray light curves show a slow decay, it seems to have an impulsive component which is rather short-lived. The following movie, taken before the slow decay started, gives us an impression that soft X-ray loops were moving up. It can be viewed here.

Another event was an LDE on 19 November. The following mpeg movie shows expanding loops/eruptions in NW and SE well before the flare. After the flare onset, a cusp structure is clearly seen here.

Further analysis of these events is ongoing.

Nariaki Nitta 21-Nov-97 (email