Halo CME on 20060816 - SOHO/LASCO C3 Data |
COMMENTS:
I expect that the axis of the corresponding MC (if indeed is present) should be oriented more
or less parallel to the ecliptic (<45 deg) plane. The direction of the axial field should then
be westward and the azimuthal field at the front edge of the ejecta should be southward,
slowly turning northward as the event progresses. The MC is expected to right handed.
Since the speed is not very high I expect that the negative Bz will not much exceed
-20nT (i.e Bz>= -20nT) thus it has a potential to produce a moderate to strong storm
with the Dst index dropping down to about -150...-190nT. But this number is the worst
case scenario which can be realized provided that we will have direct hit and the
magnetic field at the front edge will consist of mostly Bz component.
I'm not sure what
is the real Dst index at this moment but if it is indeed -100nT as reported by the World
Data Center for Geomagnetism in Kyoto, then the predicted decrease of -150..-190nT should
be from the base level of -100nT, therefore the final value of the Dst index could reach
of about -300nT.
COMMENTS AFTER ARRIVAL: The ejecta arrived on early Aug 19 and it was not observed as a typical MC but
it rather looked as a complex ejecta (Burlaga et al). I think that it was deflected southward (under the earth),
missed the target and what we observed was an edge of it. However, I'll leave the final interpretation of ACE data to expects.
Some periods of relatively strong negative Bz were, nevertheless, observed and as a result the Dst index dropped by
about 80 units reaching -180 at 2200UT on Aug 19.
- CME's Source Region is NOAA AR0904 ; P0= 16.440862; Day of Year # 228
- CME Appeared at 6 Solar Radii on 20060816 at 1642 UT
- CME Arrived at 20 Solar Radii on 20060816 at 2130 UT
- CME's Projected Speed: 800 km/sec
See more info on the event
- Estimated Travel Time is 2.48016 +/- 0.25 days
- Estimated Time of Arrival is 20060819 at 0901 (arrived at approx 0600 on Aug 19)1
- Estimated Speed of Solar Wind at 1AU is 600 km/sec (much slower, 470 km/sec)
- Estimated Direction of the Bz in the Ejecta is SOUTHWARD ( southward, turned northward )
- Estimated Magnitude of the hourly averaged Bz in the Ejecta is -7...-21 nT (-10...-12 nT)
- Estimated Change of the Dst index is -21...-196nT (decrease -80 nT from the -100nT base level)
- Estimated Level of the Geomagnetic Storm is NONE...INTENSE(MODERATE)
NONE > -30 > WEAK > -50 > MODERATE > -100 > INTENSE
1Numbers in red are estimates. Numbers in parenthesis (if any) are actual measured values
*These estimates should be compared to the observed 1 hour averaged ACE and Dst values
Real Time Dst from World Data Center for Geomagnetism, Kyoto
Real Time ACE data
Today's Space Weather
SOHO/LASCO C3 |
SOHO/LASCO C3 |
SOHO/LASCO C3 |
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Full Disk Halpha |
Full Disk SOHO/MDI |
Full Disk SOHO/EIT195 |
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Active Region Halpha |
Active Region SOHO/MDI |
Active Region /EIT195 |
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Images are courtesy of Active Region Monitor
Automaticaly Generated on Thu Aug 17 10:36:55 2006
Please, send questions and comments to Vasyl Yurchyshyn