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 nitta@isass0.solar.isas.ac.jp)
