EIT Observations of interconnected active regions

EIT Observations of
Interconnected Active Regions

Long gaps in difference movies

	1998 March 15 01:14 UT - 00:36 UT difference image	"Null test"
	1998 March 16 01:14 UT - 00:36 UT difference image	CME and flare

Click on either thumbnail for a full-resolution difference image.

. Due to a temporary change in the LASCO/EIT observing plan, there was a 38 minute gap between full-resolution Fe XII 195 Å CME watch images before most of the synoptic image sets (~ 01:00, 07:00, 13:00, and 19:00 UT) each day. (There is a half-resolution image in the gap, but it's not much help.)

While the difference image for 1998 March 16 (lower image, above) shows brighter interconnecting loop differences, the "null test" image (upper image) shows similar dark loop signatures whence bright features have moved/disappeared in 38 minutes.

The moral of the story:

The interconnections in this case, at least, change so rapidly that there are white/black shadow pairs even when the time separation is 10 - 12 minutes. With a > 30 minute separation, we have to be very careful before we can say whether the changes are flare or CME or {your favorite dynamic event} -induced.

Web curator: Joseph B. Gurman
Responsible NASA official: Joseph B. Gurman, Facility Scientist, Solar Data Analysis Center
joseph.b.gurman@gsfc.nasa.gov
+1 301 286-4767

NASA Goddard Space Flight Center
Solar Physics Branch / Code 682
Greenbelt, MD 20771

Last revised - J.B. Gurman