Sunspot Formation from Emerging Flux Ropes Observations from Flare Genesis

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Sunspot Formation from Emerging Flux Ropes -
Observations from Flare Genesis

• D. M. Rust
• P. N. Bernasconi
• M. K. Georgoulis
• Johns Hopkins University Applied Physics
  Laboratory

• B. J. LaBonte
• Institute for Astronomy
• R. A. Shine
• Lockheed Palo Alto Res. Lab
• B. Schmieder
• Observatory of Paris, Meudon

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FGE Flight Summary

• 17 days of nearly continuous solar observations
• Vector magnetograms, Dopplergrams
• Ca I (6122 Å) and H? (6563 Å) images
• 0.5" resolution, no distortion by seeing
• Highlights
• Emerging flux region on January 25, 2000
• Flare on Jan 22

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What We Found

• Magnetic fields emerged as folded flux ropes.
• The folds appeared as Moving Magnetic Features.
• MMFs streamed toward the spots.
• MMFs have twisted fields and downdrafts.
• MMFs trigger Ellerman bombs.
• Observations are inconsistent with ?-shaped
  loops MMF fields are U-shaped.
• Orientation of largest flux rope gave false
  ?-spot signal.

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AR8844 emerged rapidly on January 25, 2000
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As flux emerged, bombs appeared in H? and in the
corona at 171 Å
Nearly 300 bombs were recorded. See paper
by Georgoulis.
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Emerging Active Region 8844 Photosphere and
Longitudinal Field
Flux emerging
Photospheric filtergram with Fabry-Perot passband
centered at 6122.43 Å, on the blue wing of the Ca
I 6122.5 Å. Field of view is 90" x 90".
Line-of-sight magnetic fields White, positive
fields point towards observer. Black, negative
fields. Grey, below threshold.
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Dopplergram shows vertical motions with overlay
of cork tracks that show horizontal
motions. Dark features are downdrafts light
features are updrafts
Horizontal flux rope
Updrafts signal flux emergence
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Dopplergram shows vertical motions with overlay
of corks that shows how horizontal motions
would redistribute plasma in the growing sunspot
region. Dark features are downdrafts light
features are updrafts.
Note accumulation of corks near downdrafts
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Note bombs (red) at polarity boundaries in flux
rope
MMF with Ellerman Bombs and downdrafts
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Vector magnetograms show rotation in following
elements of flux rope
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Conclusions

• Magnetic field emerged as folded flux ropes.
• The folds appeared as Moving Magnetic Features
  even though the fields are mostly horizontal.
• Ellerman bombs, twisted fields and downdrafts
  were found in the MMFs.
• Our observations are inconsistent with ?-shaped
  loops MMF fields are U-shaped.
• Our interpretation flux ropes rising out of the
  photosphere fold, twist and reconnect to produce
  Ellerman Bombs.