05:30 UT WS West Faint front along streamer. It fades throughout C3. 06:54 UT SS West Kind of diffuse and elongated front that quickly fades. 11:30 UT WS West Ragged front along streamer that fades throughout C3. 17:06 UT WS West Ragged front along streamer. Very faint (rather) circular extensions around the C2 occulting disk by around 18:30 UT. No visible signatures in C3. GOES reported an M1.0 X-ray flare on NOAA AR 10718 (S06E02) between 16:02 - 16:14 UT with peak emission at 16:06 UT. EIT 195 images show, by 16:12 UT, a brightening on both sides of the neutral line of the AR, followed by an small dimming region to N of the AR.
NOTE: LASCO did not show evidence of any halo-like event associated with the X1.2 X-ray flare on NOAA AR 10720 (N14E08) that occurred between 00:22 - 01:02 UT with peak emission at 00:43 UT. 06:30 UT N Pole Very bright loop front above the N Pole. A faint and (HALO) diffuse envelope (shock?) can be seen all around the loop front. By 06:54 UT, the C2 occulting disk is completely covered, the LE of the event on N being already out of the C2 FOV. The event is first seen in C3 at 16:42 UT above the N Pole, the C3 occulting disk being completely covered by 07:42 UT. It develops pretty fast: the LE on N crossed the end of the C3 FOV by ~ 09:42 UT. The mean plane-of-sky speed of the LE (outermost front of the diffuse envelope ahead of the loop-like feature) at PA 002 was ~2150 km/sec (as measured on C3 in only 3 frames, then out of the FOV). For the sake of completeness, the mean plane-of- sky speed of the LE of the loop-like feature at PA 0 was ~1850 km/sec (based on C3 data, only 3 frames). GOES reported multiple M-class flares and a couple of X-ray flares on NOAA AR 10720 during the day. In particular, an M8.6 X-ray flare occurred at N16E04 between 05:54 - 07:17 UT with peak emission at 06:38 UT, is the one most likely associated to the signatures observed on C2/C3, which happened just after a compact M8.4 X-ray flare on the same AR (N14E06) between 04:26 - 04:36 UT with peak emission at 04:31 UT. EIT 195 images show signatures of the event along and N of the (east-west) neutral line of AR 10720 between 06:00 - 07:13 UT. An intensity disturbance (wave) is seen mainly to N and NW of the AR, including the activation of a large filament channel (FC). In summary, the event has therefore been determined as an asymmetric 'full' halo event, frontsided. Expanding loop-like structures follow on NNW, most likely related to continued X-ray activity on AR 10720. 14:54 UT WS West Bright ragged loop front with apparently twisted trailing structure. GOES reported an M3.2 X-ray flare on NOAA AR 10718 (S08W12) between 14:08 - 14:39 UT with peak emission at 14:23 UT. EIT 195 images show a wave on disk toward S, SW, and NW of the AR after a brightening at 14:36 UT. 23:06 UT N-NW-E Limb Very bright loop front covering practically the whole (HALO) NW quadrant. The next C2 frame (23:30 UT) shows the C2 occulting disk completely covered. Early on next day a proton storm can be seen developing in the C2 FOV (also C3). The event is first seen in C3 at 23:18 UT above the NW Limb extending from the W up to past the N Pole. It is shown as a bright loop front surrounded by a fainter and diffuse envelope (shock?). By 23:42 UT, the C3 occulting disk is completely covered. By 01:42 UT (on next day), the LE on NW already crossed the outer edge of the C3 FOV. The mean plane-of-sky speed of the LE (outermost front of the diffuse envelope ahead of the loop-like feature) at PA 329 was ~2890 km/sec (as measured on C3 in only 2 frames, as it is two difficult to discern the feature tracked in the following frame, if not already out of the FOV). For the sake of completeness, the mean plane-of- sky speed of the LE of the loop-like feature at PA 329 was ~2400 km/sec (based on C3 data, only 3 frames). GOES reported an X2.6 X-ray flare during a long duration X-ray event on NOAA AR 10720 (N15W05) between 22:25 - 23:31 UT with peak emission at 23:02 UT (on 2005/01/15), most likely associated to the signatures observed on C2/C3. EIT 195 images show a strong brightening on the aforementioned AR starting at ~ 22:36 UT, peaking by 23:12 UT (there is a small EIT data gap between 22:36 UT - 23:12 UT due to the C3 Polarization sequence taken during that time). FC to NW of the AR is blown away during the gap. In summary, the event has therefore been determined as an asymmetric 'full' halo event, frontsided.
Data degraded since early in the day by snowstorm (proton event). Degradation becomes more mportant by the end of the day. 00:06 UT E Limb Faint system of wide loop fronts developing slightly toward ESE in the aftermath of previous halo. 05:30 UT N East Brightening along streamer preceding an elongated and expanding loop-like structure. 16:54 UT N West Expanding 'curved' feature develops being 'pushed' toward N. It fades throughout C3.
09:30 UT N West Very bright loop front on the NW quadrant surrounded (HALO) by a very tenuous and diffuse excess intensity, which in fact, can be guessed (though barely) in previous frame at 09:06 UT. By 09:54 UT, the LE on NW already exited the C2 FOV, the occulting disk being completely covered. Please note that at that time, a new bright and ragged front appears above the NW Limb. The snowstorm associated with the proton event reported to start on previous day is still present on the C2/C3 images, becoming progressively more important (by around 12:30 UT) until making the C2 images completely degraded by 14:07 UT (14:19 UT for C3). The event is first seen in C3 at 09:42 UT above the NW Limb. It is shown as a bright loop front surrounded by a fainter and diffuse envelope (shock?). The next frame at 10:20 UT shows i) the diffuse envelope, ii) the loop front, and iii) a much brighter ragged front, most likely the C3 counterpart of the front appearing in C2 at 09:54 UT. The C3 occulting disk is completely covered by that time, i.e., at 10:20 UT. The outermost LE of the 'complex' event reaches the end of the C3 FOV by 11:42 UT. The mean plane-of-sky speed of the LE of the outermost front of the diffuse envelope [i.e., feature described as i)] at PA 326 was about 2185 km/sec (as measured on C3 in only 4 frames). On the other hand, the mean plane-of-sky speed of the apparently fastest outermost feature belonging to the bright loop [i.e., feature described as iii)] at PA 263 was 2350 km/sec (based on C3 data, only 4 frames). Given the superposition of structures during the development of the complex event, it is difficult to give a reliable value for the speed of the feature described as ii). GOES reported a long X-ray duration event on NOAA AR 10720: an X3.8 X-ray flare (N15W25) between 06:59 - 10:07 UT with peak emission at 09:52 UT, associated to the signatures observed on C2/C3; just after a compact C3.9 X-ray flare (N15W21) between 06:06 - 06:15 UT with peak emission at 06:10 UT. EIT 195 images show a steady increase in intensity on the AR 10720 since around 07:48 UT, peaking at 09:48 UT. Inspection of running differences show an 'intensity peak' at 08:00 UT followed by expanding loop-like structures toward NW. By 09:36 UT the loops on NW of the AR open and then disappear followed by a wave to NNE, N, and NW of the AR. Another CME signature can be seen after 09:48 UT (time of the strongest brightening): wave to NNE, NW, W, SW, and SSW on disk plus NW, W, SW, SSW off-limb. In summary, the event has therefore been determined as an asymmetric and complex 'full' halo event, frontsided. NOTE: Please note that GOES recorded previously two M2-class flares (peak emissions on 2005/01/16 @ 22:03 UT and on 2005/01/17 @ 03:21 UT). No clear signatures of associated CME can be seen in LASCO data. LASCO Data strongly degraded after proton event.
LASCO Data still strongly degraded (snowstorm) by proton event on previous day associated to the X3.8 X-ray flare and Complex Full Halo event (last C2 image at the time of writing: 12:55 UT).