GLOBAL CORONAL MASS EJECTIONS

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GLOBAL CORONAL MASS EJECTIONS
SOLI INVICTO

• Andrei N. Zhukov1,2 and Igor S. Veselovsky2,3

1Solar Influences Data analysis Center, Royal
Observatory of Belgium 2Skobeltsyn Institute of
Nuclear Physics, Moscow State University,
Russia 3Space Research Institute, Russian
Academy of Sciences, Russia
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CORONAL DIMMINGS AND CMES

• Coronal dimmings correspond to the places of mass
  evacuation during CMEs (Sterling Hudson 1997,
  Harrison et al. 2003, Zhukov Auchère 2004).
• Thompson et al. (2000) extended dimming areas
  map out well the apparent footprint of CMEs
  observed by a coronagraph

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A CME ON OCTOBER 28, 2003Evolution of the low
corona
SOHO/EIT Fe XII bandpass (195 Å) 1.5 MK plasma
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BASE DIFFERENCE MOVIE (last pre-event image
subtracted)
SOHO/EIT Fe XII bandpass (195 Å) 1.5 MK plasma
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DYNAMICS OF A GLOBAL DIMMING
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Definition a global CME is a CME that has
associated dimmings above the limb extending to
more than 180 in apparent position angle around
the solar disk.
Angular width of limb dimming 350 global!
270 global!
0 NOT global!
190 global!
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GLOBAL CMES STATISTICS
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GLOBAL CMES ERUPTION OF MULTIPOLAR MAGNETIC
FIELDS!
SOHO/EIT and SOHO/MDI
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CME MODELS ERUPTION OF A BIPOLAR REGION OF THE
MAGNETIC FIELD!
(Antiochos et al. 1999)
(Low and Zhang 2002)
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ERUPTION OF MULTIPLE MAGNETIC FLUX SYSTEMS
(T. Wang et al. 2002)
Pushing the overlying (often transequatorial)
magnetic flux by the main erupting flux of the
active region (Delannée Aulanier 1999 T. Wang
et al. 2002 Liu et al. 2006), leading to the
opening of large-scale overlying loops. WHY
DOESNT THIS HAPPEN MORE OFTEN?
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Global CMEs are NOTtoroidal CMEs (Brueckner et
al. 1998)
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Global CMEs are NOTglobal EIT waves
Running difference images
EIT wave
is global!
Base difference images
Coronal dimming is
local!
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Global CMEs are NOTglobal EIT waves

• However, in common cases of local CMEs the speed
  of EIT wave is around 300 km/s
• In the October 28, 2003 global CME event a
  Moreton wave was observed, propagating at a speed
  of 13002100 km/s
• As the speed of the incident shock wave should be
  higher than the local Alfvén speed, then r v2/2
  gt B2/8p Eruption possible?

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CONCLUSIONS

• Global CMEs are rare events characterized by a
  very large extent of coronal dimmings.
• During such extreme events a huge amount of the
  free energy is released in the form of both
  kinetic (CME) and radiative (flare) energy.
• Global CMEs correspond to the ejection of plasma
  from multiple interconnected large-scale coronal
  magnetic flux systems.
• Dimmings may be considered an important nonlocal
  manifestation of the CME initiation process and
  need to be described in a realistic CME model.
• More details in Zhukov and Veselovsky (ApJL 664,
  L131, 2007).