LASCO Activity Report for
July 26, 2004 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

2004/07/23 (Friday)

00:06 UT  SS West	Bright narrow feature preceded at 23:54 UT (on
			2004/07/22) by a diffuse and not well defined loop
 			loop front to N. Gusty outflow follows toward S. Later,
			at 01:54 and 02:30 UT, a couple of asymmetric loop 
			fronts develop toward SSW. C3 shows a very faint front
			developing mainly toward SW, which is first seen at 
			00:42 UT. It fades rapidly. On the other hand, Fe XII
			running difference images show discernible 
			brightenings on AR 0652 at 22:12 UT and 23:24 UT (no
			images between 22:36 - 23:12 UT).
			GOES recorded late on 2004/07/22 a couple of C- and 
			one M-class X-ray flares on NOAA AR 0652:
			C4.1 (N03E04) between 22:01 - 22:18 UT; Peak at 22:12 UT
			M1.6 (N04E03) between 22:40 - 23:07 UT; Peak at 22:58 UT
			C1.3 (N03E02) between 23:09 - 23:45 UT; Peak at 23:21 UT

03:30 UT  W Limb	Very very slow development of an apparently twisted
			structure.

03:54 UT  E Limb	Ragged loop front. Superposed with it, a very diffuse
			and faint loop-like feature seems seems to develop,
			moving faster. Barely visible in C3. 

07:31 UT  S West  	Diffuse and not well defined loop front (difficult to
			give an exact time of first appearance). A faint and
			diffuse loop-like front follows, starting at ~08:30 UT
			above the W Limb. C3 shows a faint front (though a 
			little bit brighter than that of previous event)
			developing mainly toward SW and spanning about 90 deg
			(first seen in C3 FOV at 08:18 UT). Fe XII running
			difference images show discernible brightenings on AR
			0652 at 06:48 UT and 07:36 UT.  
			GOES recorded a couple of C-class X-ray flares by the
			time:
			C2.3 (N03W04) between 06:41 - 07:02 UT; Peak at 06:48 UT
			C4.3 (N03W04) between 07:17 - 07:36 UT; Peak at 07:26 UT

16:06 UT  W Limb	COMPLEX HALO CME: At 16:06 UT a very faint and diffuse
			loop-like front is first seen (just barely) above the W
			Limb in C2, becoming rather bright and wide at 16:30 UT.
			Close inspection of the development of the event in C2
			show that several features contribute to the evolution 
			of the global pattern later observed, i.e.: 
			
			i) a very wide and diffuse arcade-like front (most 
			likely related to [a] -see below-). It is first seen in
			C3, above the W Limb, at 16:42 UT. Mean plane-of-sky
			speed at PA ~ 270: ~990 km/sec (though very poor 
			measurement due to the diffuseness of the leading edge, 
			based on C3 data).
			
			ii) a ragged front that first appears at 17:54 UT above
			the WSW Limb (most likely related to [b]). It is first
			seen in C3, above the WSW Limb, at 18:18 UT. Mean
			plane-of-sky speed at PA ~ 245: 540 km/sec (based on C3
			data, LE of brightest feature). 

			iii) another ragged front first seen above SW between
			18:54 - 19:31 UT (most likely related to [c]). It is
			first seen in C3, above the SW Limb, at 19:42 UT, though
			still almost hidden by feature in ii). Mean plane-of-sky
			speed at PA ~ 204: 621 km/sec (based on C3 data, LE of
			brightest feature, last point at ~ 11 solar radii).

			GOES recorded by the time a couple of C- and one M-class
			X-ray flares on NOAA AR 0652 (at the time of writing):
			[a] C1.0 (N05W04) between 16:03 - 16:15 UT; Peak at 16:09
			[b] M2.3 (N03W10) between 17:08 - 17:37 UT; Peak at 17:28
			[c] C4.1 (N03W05) between 18:02 - 18:11 UT; Peak at 18:07
			
			Among significant features observed in Fe XII running
			difference images it is worth to mention: 
			
			i) a kind of jet-like brightening at 16:12 UT on NOAA AR
			0652 and developing toward SW [a], and 

			ii) a strong brightening [b] on the same AR at 17:24 UT
			with associated ejecta of material toward SW (ejecta 
			that seems to disturb -push toward S- some loops on SW 
			of the AR 0652); by 18:36 UT the loop system is no 
			longer discernible).

22:30 UT  S West	Slow development of a circular and twisted structure 
			superposed in the LOS with the trailing material of 
			event reported to start between 18:54 - 19:31 UT (see
			COMPLEX HALO CME). By 05:54 UT on next day, is already
			seen as a very well defined structure in C2.

2004/07/24 (Saturday)

00:30 UT  N West	Bright loop front with apparently circular twisted inner
			core. Trailing material. Gusty outflow.

01:31 UT  NN West	Diffuse fan-like front. It fades throughout C2.

01:54 UT  E Limb	Ragged loop front developing slightly toward ESE. It
			fades close to the inner edge of C3 FOV.

11:06 UT  E Limb	Small ragged front apparently preceded by a faint and
			expanding elongated loop front 

18:54 UT  ES East	Very faint asymmetric loop front. It fades throughout C2.

19:31 UT  W Limb	Faint abd ragged loop front. It fades throughout C3.

23:54 UT  S West	Bright loop front developing toward SSW, trailing twisted
			structure. By the time, a faint and diffuse loop front
			develops toward SW. The latter is seen ahead a little
			bit ahead.

2004/07/25 (Sunday)

06:30 UT  N West	Small ragged fronts along streamer. They fade in C2.

13:31 UT  WS West	Faint asymmetric loop front surpassed by next event.

14:30 UT  S West	Very bright loop front develops as a 'full' halo CME.
			GOES recorded an M2.2 X-ray flare on NOAA AR 0652
			(N04W30) between 13:37 - 13:55 UT with peak emission
			at 13:49 UT. Proton storm. EIT Fe XII running difference
			images show a strong brightening at 13:48 UT on AR 0652.
			Arcade to SW of AR disturbed. Signature of a big CME
			traveling SW. At 14:48 UT, expanding loop apparently
			from just behind the WSW Limb (it makes signatures in
			C2 appear complicated to disentangle). Another strong
			brightening at 16:12 UT on the same AR. GOES recorded
			an M1.1 X-ray flare on the same AR (N08W33) between 
			14:19 - 16:43 UT with peak emission at 15:14 UT.

19:54 UT  SS West	Elongated loop front in the trailing material of the 
			previous event. Lot of gusty outflow to N (on SW).

21:54 UT  N West	Very slow development of a system of loops. Difficult
			to give an exact time of first appearance.

23:06 UT  EN East	Very faint ragged fan-like front that quickly fades.

2004/07/26 (Monday)

00:30 UT  S West	Ragged loop front in the Halo aftermath.

04:30 UT  S West	Elongated ragged loop front in the gusty outflow.