LASCO Activity Report for
December 31, 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

2004/12/29 (Wednesday)

NOTE: 	As on previous day, the multiple CMEs seen on WSW-SW along the day are
	most probably associated with the X-ray activity, i.e. multiple C- and 
	B- class X-ray flares, reported by GOES during the day on NOAA AR
	10713/10712 - by the time at around S10W90 - .

01:57 UT  N Pole	Very faint blob-like front preceded by a similar one
			(which is already close to the end of the C2 FOV). A
			couple more follow, developing toward NNW.

01:57 UT  S West	Elongated and initially bright feature. Asymmetric
			and faint loop-like structure to N.

03:21 UT  S West	Another elongated and initially bright feature that
			develops as an asymmetric loop front brighter to S.

06:21 UT  S West	Another elongated and initially bright feature that
			develops as an asymmetric loop front brighter to S.

07:45 UT  E Limb	Initially bright ragged loop front that fades when
			appearing the following event (*).

08:45 UT  E Limb	(*) Bright loop front with apparently twisted trailing
			material developing toward ESE. A very faint and 
			diffuse loop-like feature (extensions?) moving toward 
			ENE follows its development.

10:45 UT  S West	Another elongated and initially bright feature that
			develops as an asymmetric loop front (fainter than
			the previous ones). Another one at 13:22 UT. At 16:21 
			UT, a spray-like front is immediately followed, a 
			little bit to N, by a ragged loop front developing 
			toward WSW. Another (smaller) spray front at 17:21 UT. 
			By 19:45 UT, an asymmetric loop front follows, much
			brighter to S. Gusty outflow well into next day.
			Signatures most likely related to B- and C-class X-ray
			activity on NOAA AR 10713 (by the time at around S12W90).
			Note that also an M1.4 X-ray flare from 10713 (S12W90)
			was reported by GOES between 19:10 - 19:25 UT with
			peak emission at 19:20 UT.

16:45 UT  E Limb	Big, wide, and very bright loop front followed by 
			gusty outflow at 
			roughly the PA of its southern leg (ESE), well into
			next day. Some
			infalling material by the end of the day on ENE.
			Clear "pair formation" by ~ 00:21 UT on next day
			at PA ~ 67 (separation point at ~ 4 solar radii). 
			GOES reported an M2.3 X-ray flare from NOAA AR 10715
			(N04E62) between 15:57 - 16:38 with peak emission
			at 16:27 UT.
	

2004/12/30 (Thursday)

00:45 UT  S West	Diffuse spray-like front. By the time, the slow
			development of a faint system of loops along the 
			streamer starts to be discerned superposed in the LOS.
			
07:57 UT  W Limb	Faint elongated loop-like structure that fades very
			close to the inner edge of the C3 FOV.
			
10:57 UT  E Limb	Wide, big and very bright loop front. By 11:45 UT,
			extremely faint extensions can be seen surrounding 
			the C2 occulting disk. By 12:41 UT a new ragged front
			seem to develop in the trailing material toward ENE. 
			The event is first seen in C3 at 11:33 UT above the 
			E Limb; by 12:33 UT extremely faint extensions seem 
			to surround the C3 occulting disk. The mean plane-of-
			sky speed of the LE of the CME (based on C3 data)
			at PA 90 was ~ 1132 km/sec (showing practically no 
			acceleration).
			GOES reported high X-ray activity during the day 
			with a couple of M flares and multiple B- and C- 
			class X-ray flares from NOAA AR 10715. In particular, 
			it is worth to mention the following events, most 
			likely associated with the C2/C3 signatures 
			described above:
		      - a C1.3 (N04E52) between 10:10 - 10:19 UT, peak 
		        emission at 10:17 UT,
		      - a M2.2 (N03E53) between 10:33 - 11:28 UT, peak 
		        emission at 11:16 UT, and
		      - a C2.6 (N05E52) between 12:14 - 12:19 UT, peak 
		        emission at 12:17 UT.
			EIT 195 images show a strong brightening on the 
			aforementioned AR starting at 10:39 UT (clear 
			signature of the M2.2 flare). An intensity 
			disturbance (wave) is seen developing afterward 
			mainly toward W and SW of the AR.
			In summary, the event has therefore been determined 
			as an extremely faint and asymmetric 'full' halo 
			event, frontsided.

17:45 UT  E Limb	Loop front that fades and gives place to another loop
			(bubble-like) structure. By 23:30 is surpassed in the
			C2 FOV by following event.
 	
22:30 UT  E Limb	Another wide, big, and very bright loop front. By 23:30
			UT, faint extensions can be seen surrounding the C2
		 	occulting disk. By 00:54 UT on next day, a ragged 
			(faint) front can be seen developing above the W Limb,
			with ragged extensions up to the S Pole, though it is
			difficult to establish its association with the event
			developing toward E. The event is first seen in C3 at
			23:18 UT above the E Limb; by 23:42 UT faint extensions
			surround the C3 occulting disk. The mean plane-of-sky
			speed of the LE (based on C3 data) at PA 90 was ~ 1150
			km/sec (showing practically no acceleration).
			As mentioned in previous event, GOES reported high 
			X-ray activity during the day with a couple of M flares
			and multiple B- and C- class X-ray flares from NOAA AR
			10715. In particular, it is worth to mention the
			following events, very likely associated with the C2/C3
			signatures described above:
		      - a C4.1 (N03E46) between 21:41 - 21:56 UT, peak emission
			at 21:52 UT,
		      - a M4.2 (N04E46) between 22:02 - 22:28 UT, peak emission
			at 22:18 UT, and
		      - a C1.2 (N03E47) between 00:30 - 00:54 UT (on 12/31), 
			peak emission at 00:43 UT (on 12/31).
			EIT 195 images show a brightening on the aforementioned
			AR starting at 21:49 UT followed by a much stronger one
			at 22.12 UT. An intensity disturbance (wave) is seen
			developing by the time mainly toward N, S, and W of the
			AR. The ejection of a filament to NE, N, S, and W of the
			AR can be seen between ~ 22:24 - 22:36 UT.
			In summary, the event has therefore been determined as 
			an asymmetric 'full' halo event, frontsided. 

2004/12/31 (Friday)

07:31 UT  E Limb	Diffuse loop front discernible in the aftermath of 
			halo event reported to start at 22:30 UT on previous 
			day. Much outflow all across the eastern limb.

15:30 UT  E Limb	Big CME spanning in C2 all above the E Limb (as 
			projected on the plane of the sky) without clear
			extensions. By 16:54 UT, C2 shows a ragged front just
			appearing above the N Pole that spans later all above 
			the W Limb (it is difficult to say whether it is 
			related to the huge CME on E mentioned above). As for 
			C3, this latter front fades close to the inner edge.
			On 2004/12/31, among multiple B- and C-class X-ray
			flares, GOES reported an M1.2 X-ray flare (N04E38)
			between 14:38 - 14:48 UT, with peak emission at 14:45 
			UT, followed by a C6.8 (N03E38) between 14:52 and 15:04
			UT with peak emission at 14:59 UT. EIT 195 images show 
			a brightening on the aforementioned AR starting at 
			14:48 UT, clear signature of the M 1.2 X-ray flare. An
			intensity disturbance (wave) can be seen developing
			afterward mainly toward NW, W, S, and SE of the AR, 
			and by ~ 15:00 UT, a dimming region mainly to SW and S 
			of the AR. 

21:54 UT  S West	Ragged loop front.