UCMEO 93001 30718 1820/ 30717 62336 80236 0081/ 121// 233// 41355 30717 62317 92334 32181 13363 2224/ 99999 PLAIN SOHO/LASCO HALO CME July 17-18, 2023 FRONTSIDE C2 Start Time: 23:36 UT C3 Start Time: ​00:18 UT Type of CME: Assymmetric HALO CME — FRONTSIDE pa1: 008 pa2: 121 Total Width: 247 degrees Velocity Measurements: C2: 5 points 1292.2 km/sec @ PA 235.58 Acceleration: -76.96 mk/sec^2. C3: 11 points 1347.8 km/sec @ PA 235.38 Average through both(C2/C3) fields: 1355.2 km/sec Acceleration: -23.39 mk/sec^2. COMMENT: LASCO C2/C3 both show a massive partial halo CME originating from the southwestern region, then expanding outward with a bright leading edge and large core. The CME is preceded by a smaller CME that begins at 22:54 UT in the same region, causing partial overlap with the CME discussed. Halo CME is associated with two M5.0+ flares centered on S21W81 (AR 3363) starting around 23:17 UT as seen on SDO AIA 94,131,193. SDO AIA 193 also shows an eruption of filamentary material that accompanies the flares. LASCO shows extreme proton flux in the field of view. (SEP) NOAA/GOES reports a M5.0 flare from AR 3363 23:17/23:37/23:34 UT. NOAA/GOES reports a M5.7 flare from AR 3363 23:37/00:22/00:06 UT. NOAA/GOES shows an increase in proton particles with an increase in flux well over the > 10 MeV warning threshold which remains. STEREO Beacon Data COR2 A, shows the CME in the SW direction starting at 00:53 UT after a gap in data. Due to gaps in data 17:53 - 00:53 UT, velocity and position measurements could not be completed at the time. Preliminary UCMEO velocity and position measurements are delivered first. Images, movies, and time/height information for this event will be available at: https://umbra.nascom.nasa.gov/lasco/observations/halo/2023/230717 Best Regards, --James Tabourne BT [Images from original message are omitted here] ________________________________________________ Soho-halo-alert mailing list Soho-halo-alert@mail.nascom.nasa.gov https://mail.nascom.nasa.gov/mailman/listinfo/soho-halo-alert