LASCO Activity Report for
July 31, 2007 SOHO Science Daily Meeting

Event times are first frame seen in C2 camera unless otherwise noted.
These are preliminary observations for the daily SOHO science discussions.
Final analysis is reported on the Lasco CME list.
An archive of these reports is available.

Points Of Interest

2007/07/30 (Monday)

02:54 UT  EN East	Diffuse loop front.

04:54 UT  W Limb	Complex Event: a) Wide loop-like front on W, much
 	   HALO		brighter to S (hereafter Feature I), and b) ragged 
			loop front on WNW (hereafter Feature II). Some gusty
 			outflow follows on WNW. Feature I develops as a highly
 			asymmetric Halo CME (elliptical shape), the C2 
			occulting disk being fully covered by 06:06 UT. By 
			that time the LE on W is already past the outer edge
			of the C2 FOV, while on E is barely above the occulting 
			disk. It is first seen in C3 on W at 05:18 UT. The 
			mean plane-of-sky speed of the LE at PA 270 deg is 
			~620 km/sec (based on C3 data). By 10:42 UT the LE is 
			already too faint (at ~ 22 solar radii) to keep 
			accurate tracking. Feature II also develops as an
 			asymmetric Halo Event. By 05:06 UT, a diffuse signal 
			can be seen all around the N Pole up to almost the E
 			Limb. The signature imprinted by Feature II in the C2
			FOV fully covers the occulting disk by 06:30 UT. 
			Feature II is first seen in the C3 FOV above the N Pole 
			at 06:18 UT. By 10:42 UT is no longer discernible. 
			The mean plane-of-sky speed of the LE at PA 336 is 
			~475 km/sec. The HT profile of both events show
			practically no acceleration. Neither of the events 
			seems to fully cover the C3 occulting disk by
 			themselves, although if considered as a whole, the
 			complex event shows up as almost as Full Halo event 
			in the C3 FOV. The X-ray activity recorded by GOES is
 			below the A-level. EIT 195 images (running differences)
 			show no signatures on the disk of the events. However,
 			there is an extremely faint signature (barely
 			discernible) of an apparently backsided event all 
			above the NW Limb starting at around 04:48 UT. In 
			summary, the event was determined as a Complex Full
			Halo Event (with at least 2 components), most likely
 			backsided.

12:06 UT  S West	Ragged loop front.

19:26 UT  WS West	Ragged blob-like front starts to be disernible. It
			fades in C3, very close to its inner edge.

2007/07/31 (Tuesday)

	05:06 - 10:54 UT	LASCO Data Gap (C2 time).

11:06 UT  E Limb	System of loop fronts already under development after
 			data gap.

Last C2 image available by the time of writing:  12:30 UT