The Relationship Between CMEs and Post-eruption Arcades Peter T. Gallagher, Chia-Hsien Lin, Claire...
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Transcript of The Relationship Between CMEs and Post-eruption Arcades Peter T. Gallagher, Chia-Hsien Lin, Claire...
The Relationship Between CMEs and Post-
eruption Arcades
The Relationship Between CMEs and Post-
eruption ArcadesPeter T. Gallagher, Chia-Hsien
Lin, Claire Raftery, Ryan O. Milligan
Peter T. Gallagher, Chia-Hsien Lin, Claire Raftery, Ryan O.
Milligan
Recap of CME MorphologyRecap of CME Morphology
“Typical” event consists of 3 components:Ejection of coronal magnetic field and massEjection of filament/prominence field and
massHeating of > 10MK flare coronal loops and
acceleration of flare particles (Krucker) Strength of each component can vary
between events, but all are present to some degreeHow are they related?
“Typical” event consists of 3 components:Ejection of coronal magnetic field and massEjection of filament/prominence field and
massHeating of > 10MK flare coronal loops and
acceleration of flare particles (Krucker) Strength of each component can vary
between events, but all are present to some degreeHow are they related?
Non-Dipole Coronal TopologyNon-Dipole Coronal Topology
Field of two dipoles – axi-symmetricLarge global at Sun center, weaker near
surfaceMust have 4-flux system with separatrix
bdys, and null
Field of two dipoles – axi-symmetricLarge global at Sun center, weaker near
surfaceMust have 4-flux system with separatrix
bdys, and null
Non-eruptionNon-eruption• Bipolar (one polarity inversion line) initial magnetic field • Filament-field formation by shearing and reconnection• See pronounced expansion & kinking – but no eruption
Underlying physics: Corona has no lid Magnetic field lines can stretch indefinitely
without breakingFree to open slowly in response to photospheric
stress and gas pressure (rather than erupt as CME) Slow opening (not associated with filament
channels) observed to occur continuously in large-scale corona
• Bipolar (one polarity inversion line) initial magnetic field • Filament-field formation by shearing and reconnection• See pronounced expansion & kinking – but no eruption
Underlying physics: Corona has no lid Magnetic field lines can stretch indefinitely
without breakingFree to open slowly in response to photospheric
stress and gas pressure (rather than erupt as CME) Slow opening (not associated with filament
channels) observed to occur continuously in large-scale corona
QuickTime™ and a decompressor
are needed to see this picture.
(from, DeVore et al, 2005; Aulanier et al, 2005)
Breakout ModelBreakout Model
2D multi-polar initially potential field Create filament channel by simple footpoint
motions Outward expansion drives breakout
reconnection in corona
2D multi-polar initially potential field Create filament channel by simple footpoint
motions Outward expansion drives breakout
reconnection in corona
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Breakout ModelBreakout Model
Breakout reconnection allows for explosive eruption
Flare current sheet, flare reconnection, and twisted flux rope all consequences of ejection
CME with no flare possible for slow eruptions
Breakout reconnection allows for explosive eruption
Flare current sheet, flare reconnection, and twisted flux rope all consequences of ejection
CME with no flare possible for slow eruptions
QuickTime™ and aBMP decompressor
are needed to see this picture.QuickTime™ and a
BMP decompressorare needed to see this picture.
Open CME questionsOpen CME questions
What are the forces governing the propagation and expansion of CMEs?
Is there a relationship between CME kinematics and post-flare loop kinematics?
What are the forces governing the propagation and expansion of CMEs?
Is there a relationship between CME kinematics and post-flare loop kinematics?
CME KinematicsCME Kinematics
Kinematics are governed by force balance equation:
Kinematics are governed by force balance equation:
€
ρ D ˆ v
Dt= −∇P + ˆ J × ˆ B −
GMρ
R2ˆ R
€
ˆ J =c
4π∇ × ˆ B
CME ModelsCME Models
• All models are based on the principle that CMEs are driven by the sudden release of the free magnetic energy stored in pre-eruptive coronal magnetic fields.
– Resistive MHD models: where magnetic reconnection in a current sheet plays an important role in triggering the CME onset and in sustaining the eruption.
– Ideal resistive hybrid: where eruption is triggered by an ideal loss of equilibrium of the magnetic field but that subsequent formation of a current sheet and magnetic reconnection is crucial for sustaining the eruption and allowing a magnetic flux rope to escape.
– Non-force free models: the weight of the prominence mass plays a important role in building up the magnetic energy to exceed that of the open-field limit, and that a sudden drop of the prominence weight triggers the eruption.
• All models are based on the principle that CMEs are driven by the sudden release of the free magnetic energy stored in pre-eruptive coronal magnetic fields.
– Resistive MHD models: where magnetic reconnection in a current sheet plays an important role in triggering the CME onset and in sustaining the eruption.
– Ideal resistive hybrid: where eruption is triggered by an ideal loss of equilibrium of the magnetic field but that subsequent formation of a current sheet and magnetic reconnection is crucial for sustaining the eruption and allowing a magnetic flux rope to escape.
– Non-force free models: the weight of the prominence mass plays a important role in building up the magnetic energy to exceed that of the open-field limit, and that a sudden drop of the prominence weight triggers the eruption.
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QuickTime™ and aTIFF (Uncompressed) decompressor
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QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (Uncompressed) decompressor
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Comparison of eventsComparison of events
21-apr-2002
17-Dec-2006
vmax
(km/s)
~2,4001-10
~790~1
amax
(m/s/s)
Duration(hours)
~20 ~13
X-ray magnitud
e
X1.1 C2.0