Reconnection

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Reconnection Prominence Magnetic Fields
coronagraph (CME)
Ha limb (prominence)
X-ray (flare loops)
Ha disk (flare ribbons)
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Loss of Equilibrium Model
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Trajectories Assuming M 0.1
A
M
A
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Power Processed Through Current Sheet
for M 0.1
A
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Chromospheric Evaporation
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I µ 1/R ln(R/r0)
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torus instability (see Bateman 1978)
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3D Loss-of-Equilibrium Model
Titov Démoulin (1999)
1. flux rope
3 field sources
3. line-current
2. magnetic   charges
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Forces Acting on Flux Rope
force vectors
restoring forces near feet
out of plane twisting
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current density
Kliem Török (2004)
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Simulation of Kliem Török
1. line current replaced by quadrupole 2.
subcritical twist for helical kink 3. torus
center near surface
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Line-Tied Evolution
erupted configuration
initial configuration
vertical field at surface
potential field
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Evolution of Flux-Rope Footprint Caused by
Reconnection
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Transient Coronal Holes as Seen by EIT
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Coronal Hole Evolution During 4 Hours
18 Dec 1998
18 Dec 1998
EIT soft X-ray images (171 Å)
10830 Å contours magnetogram
(images prepared by K. Harvey)
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Transient Coronal Holes as Seen by TRACE
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Some Unanswered Questions
How are stressed magnetic fields formed?
1.
issue of reverse currents
What determines the rate of reconnection?
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kinetic processes
turbulence
To what extent are flares CMEs predictable?
3.
complexity