The Relationship Between CMEs and Posteruption Arcades Peter
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 > 10 MK 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
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) De. Vore et al, 2005; Aulanier et al, 2005) G Slow opening (not(from, associated with filament channels) observed to occur continuously in
Breakout Model G 2 D 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
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?
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.
Overview of 17 -Dec-2006 Event
CME Kinematics
Post-flare arcade kinematics
CME and Arcade Kinematics
24 -hours
Comparison of events vmax (km/s) amax (m/s/s) Duration (hours) X-ray magnitude 21 -apr 2002 ~2, 400 1 -10 17 -Dec 2006 ~790 ~1 ~20 ~13 X 1. 1 C 2. 0
A comparable event: 21 -Apr 2002
Conclusions G Is there a relationship
- Slides: 26