Note on tracking Sun-Earth connection event

ICME Event: 2011/10/24

Observer: Eleni Nikou on 2019/06

1. ICME
  1.1. Catalog
     # Identified in ICME catalogs: Richardson & Can List
      RC catalog:
      Disturbance start time: 2011/10/24 18:31 UT
      Ejecta      Start time: 2011/10/24 22:00 UT
      Ejecta      End   time: 2011/10/25 16:00 UT
      dv = 150 km/s, v = 460 km/s, vmax= 510 km/s
      MC index:     2
      Dst:        -147 nT
      Suggested source CME: 2011/10/22 00:05 UT
      V_transit:  630 km/s
      
  1.2. Comments
      Overall ICME quality index: 3
      ICME signatures: Bmax: 24.8 nT
               ICME signatures: low beta after 00:00 UT, relatively smooth v, B smooth by parts
    
      Disturbance time 460 km/s  -> search window 3-4 days -> 2011/10/20-21

2. CME
   2.1. A. Candidate A
    A.1. LASCO:    
      #CME 2011/10/22 01:25 UT, halo CME
           

    A.2 .STEREO: 
           Also seen as a CME in COR2-A and COR2 B (first frame at COR2-A 01:24 UT)
	   Front-side CME, towards the nothern hemisphere

    A.3. AIA & GOES
	   corresponding flare: no flare is given at that time by GOES.
       
Solar Monitor gives a C1.7 flare at 02:11 UT but it can't be the same one since the C2 and COR2 observations start before that time.

    A.4 Comment: 
 
	   Could be the source: The timing and orientation is in agreement with the observations. It is a fast CME and it makes sense to arrive in less than 3-4 days (based on the in sity velocity and  arrival time approximation)

    Based on multi-wavelength observations it seems that there was a filament at the NW hemisphere that erupted. We can also see dimmings at the same area at the time of the halo CME.
   
3. Other Comments

     CDAW gives a partial halo CME on 2011/10/20 at 03:36:05 UT, but it is a back-side event.
     
      The following events were only captured by STEREO-A and appear as partial halo CMEs, but are on the western limb and they are not Earth directed. 

     21-Oct-2011 12:53   13:00   13:08   M1.3      11319
     21-Oct-2011 13:40   13:44   13:46   C1.5      11319

4. Summary
    SW index 3
    Source index 1
    Overall index 1