Optimization code with weighting function for the reconstruction of coronal magnetic fields

Wiegelmann, T.

doi:10.1023/b:sola.0000021799.39465.36

Cited by 459 publications

(447 citation statements)

References 23 publications

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“…We then correct for projection effects and transform the line-of-sight and transverse components of the vector magnetic field to the heliographic components as described in Gary & Hagyard (1990). Finally, an NLFFF extrapolation is made to obtain the magnetic field configuration with the optimization method (Wheatland et al 2000;Wiegelmann 2004). Figure 3b depicts the magnetic field lines and the 3600 Å contours.…”

Section: Data Analysis and Resultsmentioning

confidence: 99%

Understanding the white-light flare on 2012 March 9: evidence of a two-step magnetic reconnection

Hao¹,

Guo²,

Dai³

et al. 2012

A&A

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Aims. We attempt to understand the white-light flare (WLF) that was observed on 2012 March 9 with a newly constructed multiwavelength solar telescope called the Optical and Near-infrared Solar Eruption Tracer (ONSET). Methods. We analyzed WLF observations in radio, Hα, white-light, ultraviolet, and X-ray bands. We also studied the magnetic configuration of the flare via the nonlinear force-free field (NLFFF) extrapolation and the vector magnetic field observed by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO). Results. Continuum emission enhancement clearly appeared at the 3600 Å and 4250 Å bands, with peak contrasts of 25% and 12%, respectively. The continuum emission enhancement closely coincided with the impulsive increase in the hard X-ray emission and a microwave type III burst at 03:40 UT. We find that the WLF appeared at one end of either the sheared or twisted field lines or both. There was also a long-lasting phase in the Hα and soft X-ray bands after the white-light emission peak. In particular, a second, yet stronger, peak appeared at 03:56 UT in the microwave band. Conclusions. This event shows clear evidence that the white-light emission was caused by energetic particles bombarding the lower solar atmosphere. A two-step magnetic reconnection scenario is proposed to explain the entire process of flare evolution, i.e., the firststep magnetic reconnection between the field lines that are highly sheared or twisted or both, and the second-step one in the current sheet, which is stretched by the erupting flux rope. The WLF is supposed to be triggered in the first-step magnetic reconnection at a relatively low altitude.

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Section: Data Analysis and Resultsmentioning

confidence: 99%

Understanding the white-light flare on 2012 March 9: evidence of a two-step magnetic reconnection

Hao¹,

Guo²,

Dai³

et al. 2012

A&A

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“…The preprocessed bottom boundary are used by the optimization code to extrapolate the NLFFF (Wheatland et al 2000;Wiegelmann 2004). Selected field lines are plotted in Figure 1.…”

Section: Analysis and Resultsmentioning

confidence: 99%

A filament supported by different magnetic field configurations

et al. 2010

Self Cite

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Abstract.A nonlinear force-free magnetic field extrapolation of vector magnetogram data obtained by THEMIS/MTR on 2005 May 27 suggests the simultaneous existence of different magnetic configurations within one active region filament: one part of the filament is supported by field line dips within a flux rope, while the other part is located in dips within an arcade structure. Although the axial field chirality (dextral) and the magnetic helicity (negative) are the same along the whole filament, the chiralities of the filament barbs at different sections are opposite, i.e., right-bearing in the flux rope part and left-bearing in the arcade part. This argues against past suggestions that different barb chiralities imply different signs of helicity of the underlying magnetic field. This new finding about the chirality of filaments will be useful to associate eruptive filaments and magnetic cloud using the helicity parameter in the Space Weather Science.

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“…method Developed by Wiegelmann (2004) by minimizing a joint measure for the normalized Lorentz force and the divergence of the field, given by the function, …”

Section: Boundary Integral Equation (Bie) Methods Proposed Bymentioning

confidence: 99%

Accuracy analysis and application of extrapolation of force-free fields in solar active and quiet regions

Liu¹,

Zhang²,

Su³

et al. 2012

Proc. IAU

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Abstract. In this paper, the availability, applicability and deviation of nonlinear force-free (NLFF) fields extrapolated by Approximate Vertical Integration (AVI), Boundary Integral Equation (BIE) and Optimization (Opt.) methods are studied based on the comparison with two semi-analytical fields (Low & Lou 1990). These NLFF extrapolations based on the observational vector magnetograms are used to study the spatial magnetic field in the quiet Sun.

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Optimization code with weighting function for the reconstruction of coronal magnetic fields

Cited by 459 publications

References 23 publications

Understanding the white-light flare on 2012 March 9: evidence of a two-step magnetic reconnection

Understanding the white-light flare on 2012 March 9: evidence of a two-step magnetic reconnection

A filament supported by different magnetic field configurations

Accuracy analysis and application of extrapolation of force-free fields in solar active and quiet regions

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