CME - Geomagnetic Storm Analysis Page

Key to terms, in order of probable puzzlement produced:

    NVA:  No Visible Activity
    M:       GIF or Mpeg movie link
    Ap:      Ap index, a measure of the magnitude of a geomagnetic storm
    PA:     Position Angle (angle on solar limb, measured CCW from due north)
    AR:     Active Region number (assigned by NOAA's Space Environment Center)
    C2:       Link to LASCO C2 movie
    C3:       Link to LASCO C3 movie
    cad:      Cadence (period between observations)
    CME:  Coronal Mass Ejection

Information for minor storm reported June 26, 1998, Ap 48:
Day CHIP (He I -- chromosphere) EIT (Fe XII -- coronal disk) MK3 (low corona limb) LASCO (outer corona limb)
Jun 21 M: {17:05-21:00} No data. No data. C2: {00:15-23:55} 
C3: {00:25-23:45}
8:55: Faint halo
17:05-21:00: PA 320: Large prominence. 
PA 135: smaller prominence.		 18:56-23:55: PA 320: Streamer swells considerably, probably start of CME
20:48: PA 310: Bright spot, eruptive shape appear in prominence
Jun 22 M: {20:14-21:56} M: {13:58-23:52, 1 hr cad} No data. C2: {00:15-23:58} 
C3: {00:25-23:52, gap 18:49-22:27}
02:46: PA 320: Large, slow (perhaps large earthward component of velocity) CME.
07:34: PA 220: Another CME, blends temporally a bit with the first.
10:48: PA 65: Faint, slow CME
17:57: AR 8249 (5W, 30S): Small expulsion NVA
20:14-21:56: PA 320: Large prominence gone. 
(10E, 20S): small filament moves S. 
PA 270: Moderate jet on limb.		 19:15: AR 8251 (70W, 15 N): Small expulsion 20:45: PA 300: Another small ejection (maybe just part of the streamer)
Jun 23 M: {19:52-22:05}  M: {00:04-23:51} No data. C2: {00:28-23:55} 
C3: {00:40-23:44}
NVA 00:40: PA 65: Remnants of CME from previous day seen leaving
NVA 03:59: PA 240: Moderate CME
07:57: PA 300: Dimmed stream expelled 08:59: PA 300: Small expulsion
NVA 19:37: PA 60: Prominence near limb oscillates, fades momentarily 20:55: PA 60: Moderate CME
20:34: PA 300: Some sort of eruption NVA NVA 
21:25: AR 8249 (30W, 30S): Small surge NVA  NVA 
Jun 24 M: {17:03-22:24} M:{00:03-22:06} No data. C2:{00:27-11:55} 
C3:{00:44-11:44}
NVA 00:27: PA 60: CME in progress at start of day.
05:35: AR 8253 (75E, 20N): Bright swelling NVA
NVA 08:44: PA 150: Bizarre, untrustworthy bent streamer in C3.
NVA 09:27: PA 110: Small expulsion
17:59-18:27: AR (35W, 40S): Surge NVA No data.
19:06-20:13: F (10E, 30S): Surge NVA
19:09-19:29, 20:39-20:48: AR 8253 (65E, 20N): Surges 19:14-20:38: AR 8253 (70E,20N): Bright swelling
20:33-21:54: F (10E, 50N): Filament disappearance with outward jet. NVA 
 

Information for severe storm reported May 4, 1998, Ap 101:
Day CHIP (He I -- chromosphere) EIT (Fe XII -- coronal disk) MK3 (low corona limb) LASCO (outer corona limb)
Apr 30 No data. M:{00:04-23:51, 20min cad} No data. C2: {00:28-23:28, 30 min cad} 
C3: {00:40-23:40, 1 hr cad}
 NVA 00:28: PA 320:  Tail of material leaving, from previous day. 
 NVA 06:27: PA 50: surge in streamer
 NVA 15:00: PA 50: surge in streamer
21:37-23:06: AR 8210 ( 10 W, 5 S) seems to expel material.  23:00: PA 280: Some material ejected just S. of streamer.
May 1  M:{16:43-22:04} M:{00:03-23:51} {16:44-22:04} 
 		 C2: {00:28-23:56, gaps 00:28-7:31, 16:27-23:56} 
C3: {00:40-23:40, same gaps}
 NVA 10:00: PA 50: surge in streamer
16:49-18:07: AR 8206 ( 60W, 30S): surge on N end.  NVA 20:00: PA 110: Some swelling of streamer. NVA
 16:43-22:04: AR 8210 ( 5W, 5S) quite active, with motion of material, small surges. 18:36-22:58: AR 8210: Bright flashes in its SE corner; esp. bright starting 22:58; also some dimming E. of 8210 at 22:58.   23:56: PA 250: after time gap, there seems to be an ejection underway
May 2 M:{17:08-22:20} M: {00:03-23:56} {17:11-22:22} 
 		 C2: {00:58-23:48} 
C3: {00:40-23:52}
03:54: NE AR 8210 ( 10W,5S): Small ejection possible from NE corner, with dimming to NE. NVA
04:55: AR 8210: Another small ejection, with dim material travelling NE. 05:31: PA 240: Small CME
13:42: AR 8210: Huge eruption; massive dimming evident to N immediately afterward. 14:06: Huge halo CME (mostly in N)
17:50: N AR 8210: Faint filament seems to disappear.  NVA  NVA  
20:47: SE AR 8210: Small filament-like structure appears, takes a semi-circular shape, then quickly collapses. 21:28: SE AR 8210:  More brightening. Some swelling of streamer at PA 240 througuout run. 21:20: PA 240: Small CME 
Comments: the CME which caused the storm was almost certainly the huge eruption seen in EIT at 13:42 on May 2 (this also corresponded to an X-class flare).  Unfortunately, this was not during CHIP's viewing window; however, the smaller CME at the end of May 2 was visible in CHIP.  AR 8210 was indeed quite active; in a CHIP movie of Apr 28 (M), it appears to emit material to the NE, perhaps to AR 8214.

Revised 6 Aug 1998 by Mark Neyrinck