Nonlinear Force Free Field Extrapolation

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Non-linear Force Free Field Extrapolation

• Yang Liu Stanford University
• yliu_at_solar.stanford.edu

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Method

• Boundary Integral Equation Representation (Yan
  Sakurai 2000).
• Inputs Vector magnetic field at solar surface.

More detail
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AR9077

• Boundary Data and Extrapolated Field Lines.

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AR9077

• Boundary Data and Extrapolated Field Lines.

5
AR9077

• Boundary Data and Extrapolated Field Lines.

6
AR9077

• Flux Rope ?

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AR9077

• Flux Rope ?

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AR9077

• Flux Rope ?

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AR0386

• Boundary Data and Extrapolated Field lines.

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AR0386

• .

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AR0386

• .

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AR0386

• .

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AR0306

• Boundary Data And Extrapolated Field Lines.

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AR0306
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AR0397

• Boundary Data And Extrapolated Field Lines.

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AR0397
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Can NLFFF modeled fields reproduce changes of
coronal structure seen in observations?

• Yes?

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Can NLFFF reproduce changes of corona? (cont.)
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Can NLFFF reproduce changes of corona? (cont.)
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Can NLFFF reproduce changes of corona? (cont)

• Bleybel et al. (2002) A.Ap estimate changes of
  energy and helicity.

Before Flare
After Flare
NLFFF
LFFF
Potential Field