The Relationship Between CMEs and Post-eruption Arcades Peter T. Gallagher, Chia-Hsien Lin, Claire Raftery, Ryan O. Milligan

Recap of CME Morphology G “Typical” event consists of 3 components: G Ejection of coronal magnetic field and mass G Ejection of filament/prominence field and mass G Heating of > 10MK flare coronal loops and acceleration of flare particles (Krucker) G Strength of each component can vary between events, but all are present to some degree G How are they related? G “Typical” event consists of 3 components: G Ejection of coronal magnetic field and mass G Ejection of filament/prominence field and mass G Heating of > 10MK flare coronal loops and acceleration of flare particles (Krucker) G Strength of each component can vary between events, but all are present to some degree G How are they related?

Non-Dipole Coronal Topology G Field of two dipoles – axi-symmetric G Large global at Sun center, weaker near surface G Must have 4-flux system with separatrix bdys, and null G Field of two dipoles – axi-symmetric G Large global at Sun center, weaker near surface G Must have 4-flux system with separatrix bdys, and null

Non-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: G Corona has no lid G Magnetic field lines can stretch indefinitely without breaking G Free to open slowly in response to photospheric stress and gas pressure (rather than erupt as CME) G 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: G Corona has no lid G Magnetic field lines can stretch indefinitely without breaking G Free to open slowly in response to photospheric stress and gas pressure (rather than erupt as CME) G Slow opening (not associated with filament channels) observed to occur continuously in large-scale corona (from, DeVore et al, 2005; Aulanier et al, 2005)

Breakout Model G 2D multi-polar initially potential field G Create filament channel by simple footpoint motions G Outward expansion drives breakout reconnection in corona G 2D multi-polar initially potential field G Create filament channel by simple footpoint motions G Outward expansion drives breakout reconnection in corona

Breakout Model G Breakout reconnection allows for explosive eruption G Flare current sheet, flare reconnection, and twisted flux rope all consequences of ejection G CME with no flare possible for slow eruptions G Breakout reconnection allows for explosive eruption G Flare current sheet, flare reconnection, and twisted flux rope all consequences of ejection G CME with no flare possible for slow eruptions

Ideal Instability

Open CME questions G What are the forces governing the propagation and expansion of CMEs? G Is there a relationship between CME kinematics and post-flare loop kinematics? G What are the forces governing the propagation and expansion of CMEs? G Is there a relationship between CME kinematics and post-flare loop kinematics?

CME Kinematics G Kinematics are governed by force balance equation:

Standard Flare Model

CME 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.

Overview of 17-Dec-2006 Event

CME Kinematics

Post-flare arcade kinematics

CME and Arcade Kinematics

24-hours

~ ~

Comparison of events 21-apr Dec v max (km/s) ~2, ~790 ~1 a max (m/s/s) Duration (hours) ~20~13 X-ray magnitude X1.1C2.0

A comparable event: 21-Apr- 2002

Conclusions G Is there a relationship