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Orsay, 07.03.2007 5 th SECCHI Consortium Meeting: Wiegelmann et al.: SECCHI-3D reconstruction software Wiegelmann, Inhester, Feng, Ruan, Thalmann, Podlipnik SECCHI-3D reconstruction software Tools to compute coronal magnetic fields Selfconsistent magnetohydrostatic equilibria Feature recognition Stereoscopy Tomography
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Orsay, 07.03.2007 5 th SECCHI Consortium Meeting: Wiegelmann et al.: SECCHI-3D reconstruction software Aim: 3D Reconstruction of Solar Corona The 2 Viewpoints of STEREO help us for a 3D-reconstruction. But: Image data are not sufficient (see talk of Feng) Essential: Magnetic field information. Our tools use combined data sets of SECCHI with photospheric B-field measurements from various instruments (SOHO, HINODE, SOLIS)
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Orsay, 07.03.2007 5 th SECCHI Consortium Meeting: Wiegelmann et al.: SECCHI-3D reconstruction software Coronal magnetic field codes Potential, linear and nonlinear force-free extrapolation codes -Cartesian (Active Regions) and -Spherical (Full Sun) geometry Selfconsistent magnetohydrostatic codes: B-field + Plasma in one MHS-model -Cartesian -Spherical
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Orsay, 07.03.2007 5 th SECCHI Consortium Meeting: Wiegelmann et al.: SECCHI-3D reconstruction software ModelMathematicsObservations needed Validity Potential Fields Line of sight magnetogram (Global) current free regions, quiet sun Linear Force- Free Fields LOS magnetogram + observations of plasma structures Local in active regions, low-beta plasma Non Linear Force-Free Vectormagnetogram (3 times more data, ambiguities, noise) Active regions, low beta plasma in low corona MHS Equilibrium Vectormagnetogram + Tomographic Inversion of density Helmet streamer, finite beta plasma, full solar corona Better Models More Challenging Computational + Observational
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Orsay, 07.03.2007 5 th SECCHI Consortium Meeting: Wiegelmann et al.: SECCHI-3D reconstruction software Easy to compute Require only LOS-Magnetograms
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Orsay, 07.03.2007 5 th SECCHI Consortium Meeting: Wiegelmann et al.: SECCHI-3D reconstruction software Very Challenging Vector-Magnetograms Pre-processing
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Orsay, 07.03.2007 5 th SECCHI Consortium Meeting: Wiegelmann et al.: SECCHI-3D reconstruction software
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Orsay, 07.03.2007 5 th SECCHI Consortium Meeting: Wiegelmann et al.: SECCHI-3D reconstruction software Measured loops in a newly developed AR (Solanki et al., Nature 2003) Potential field reconstruction Linear force-free reconstructionNon-linear force-free reconstruction Comparison of observed magnetic loops and extrapolations from photospheric measurements (Wiegelmann et al., A&A 2005) Nonlinear force-free Models are superior.
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Orsay, 07.03.2007 5 th SECCHI Consortium Meeting: Wiegelmann et al.: SECCHI-3D reconstruction software What do coronal B-field models provide? 3D loop structure +projections on 2 images Length + shape of loops Magnetic field strength Electric current density (Free) magnetic energy Helicity Stereoscopy Scaling Laws CME-onset
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Orsay, 07.03.2007 5 th SECCHI Consortium Meeting: Wiegelmann et al.: SECCHI-3D reconstruction software What does SECCHI provide? Rigorous Test of B-field models. Obtain free model parameters. Test scaling laws. Get plasma parameters along loops - Temperature - Density - Pressure Compare selfconsistent MHS-models with coronagraph images (Talk of Ruan) Compare real + artificial images, Loops + B-lines Modeling, Tomography
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Orsay, 07.03.2007 5 th SECCHI Consortium Meeting: Wiegelmann et al.: SECCHI-3D reconstruction software Single viewpoint: SOHO/EIT, TRACE Use B-Field for feature-recognition (Wiegelmann et al., Sol. Phys. 2005) Compute the coronal magnetic field. Project 3D field lines onto an EUV-image. Emissivity and gradient along projected field lines. Compare field lines and plasma. How well are they aligned? Alternative: Extract 1-D loops out of the EUV- images (see talk of Inhester) and compare with projections of magnetic field lines thereafter.
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Orsay, 07.03.2007 5 th SECCHI Consortium Meeting: Wiegelmann et al.: SECCHI-3D reconstruction software EIT-image and projections of magnetic field lines for a potential field ( α=0). (bad agreement) Linear force-free field with α=+0.01 [Mm -1 ] (bad agreement) We use a linear force-free model with MDI-data and have the freedom to choose an appropriate value for the force-free parameter α.
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Orsay, 07.03.2007 5 th SECCHI Consortium Meeting: Wiegelmann et al.: SECCHI-3D reconstruction software Linear force-free field with α=-0.01 [Mm -1 ] (better agreement) 3D-magnetic field lines, linear force-free α=-0.01 [Mm -1 ]
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Orsay, 07.03.2007 5 th SECCHI Consortium Meeting: Wiegelmann et al.: SECCHI-3D reconstruction software SUMER Dopplergram in NeVIII ( 77 nm) and a 2-D-projection of some field lines. (Marsch, Wiegelmann, Xia, A&A 2004) Mass flux density inferred from Doppler- shift and intensity from SUMER observations. up down 3D-Loops guide Data Analysis
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Orsay, 07.03.2007 5 th SECCHI Consortium Meeting: Wiegelmann et al.: SECCHI-3D reconstruction software Rates quality of magnetic field reconstruction. Identifies coronal loops. For a linear force-free model the method computes the optimal force-free parameter α. The method tells us also how good the assumption “linear force-free” is. (This assumption is good if the optimal value α is the same on all loops.) Two viewpoints will be more restrictive. Magnetic Stereoscopy, Talk of Feng What does the method provide?
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Orsay, 07.03.2007 5 th SECCHI Consortium Meeting: Wiegelmann et al.: SECCHI-3D reconstruction software Magnetic fields and coronal tomography a)Use only line of sight density integrals. Wiegelmann and Inhester, Sol. Phys, 2003 b)Use only magnetic field data. c)Use both line of sight density integrals and magnetic field as regularization operator. Magnetic Models support Tomography, Regularization
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Orsay, 07.03.2007 5 th SECCHI Consortium Meeting: Wiegelmann et al.: SECCHI-3D reconstruction software Summary We developed tools for the 3D-reconstruction of the solar corona (global and local). Combined data-analysis of SECCHI-data with magnetic field information are more powerful than 2 STEREO-viewpoints alone. It is fortunate that we have STEREO and HINODE data available at the same time. SECCHI + HINODE + Reconstruction Tools = Corona in 3D
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Orsay, 07.03.2007 5 th SECCHI Consortium Meeting: Wiegelmann et al.: SECCHI-3D reconstruction software References (Selection) Coronal magnetic field models T. Wiegelmann: Optimization code with weighting function for the reconstruction of coronal magnetic fields. (Sol. Phys., Vol. 219: 87-108, 2004.)Optimization code with weighting function for the reconstruction of coronal magnetic fields. T. Wiegelmann, A. Lagg, S.K. Solanki, B. Inhester, J. Woch: Comparing magnetic field extrapolations with measurements of magnetic loops. (A&A, Vol. 433, 701-705, 2005.)Comparing magnetic field extrapolations with measurements of magnetic loops. T. Wiegelmann, B. Inhester, T.Sakurai: Preprocessing of vector magnetograph data for a nonlinear force-free magnetic field reconstruction. (Sol. Phys, Vol. 233, 215-232, 2006.)Preprocessing of vector magnetograph data for a nonlinear force-free magnetic field reconstruction. B. Inhester and T. Wiegelmann : Nonlinear force-free magnetic field extrapolations: comparison of the Grad-Rubin and Wheatland-Sturrock-Roumeliotis algorithm.Nonlinear force-free magnetic field extrapolations: comparison of the Grad-Rubin and Wheatland-Sturrock-Roumeliotis algorithm. (Sol. Phys., Vol. 235,201-221, 2006) T. Wiegelmann and T. Neukirch: An optimization principle for the computation of MHD equilibria in the solar corona. (A&A, Vol. 457, 1053-1058, 2006.) An optimization principle for the computation of MHD equilibria in the solar corona. T. Wiegelmann: Computing nonlinear force-free coronal magnetic fieldsComputing nonlinear force-free coronal magnetic fields in spherical geometry. in spherical geometry. (Solar Physics, in press, 2007)
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Orsay, 07.03.2007 5 th SECCHI Consortium Meeting: Wiegelmann et al.: SECCHI-3D reconstruction software Stereoscopy T. Wiegelmann and T. Neukirch: Including Stereoscopic Information in the Reconstruction of Coronal Magnetic Fields. (Sol. Phys., Vol. 208: 233-251, 2002.)Including Stereoscopic Information in the Reconstruction of Coronal Magnetic Fields. T. Wiegelmann and B.Inhester: Magnetic Stereoscopy. (Solar Physics, Vol. 236, 25-40, 2006.)Magnetic Stereoscopy. L.Feng, T. Wiegelmann, B.Inhester, S.K. Solanki, W.Q. Gan, P. Ruan : Magnetic Stereoscopy of Coronal Loops in NOAA 8891. (Sol. Phys., accepted.) Magnetic Stereoscopy of Coronal Loops in NOAA 8891. B.Inhester: Stereoscopy Basics for the Stereo mission (ISSI publication, submitted.) Tomography T. Wiegelmann and B. Inhester: Magnetic modeling and tomography: First steps towards a consistent reconstruction of the solar corona. (Solar Physics, Vol. 214: 287-312, 2003.)Stereoscopy Basics for the Stereo missionMagnetic modeling and tomography: First steps towards a consistent reconstruction of the solar corona. Feature recognition T. Wiegelmann, B. Inhester, A. Lagg, S.K. Solanki: How to use magnetic field information for coronal loop identification? (Sol. Phys., Vol. 228, 67-78, 2005.) How to use magnetic field information for coronal loop identification?
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Orsay, 07.03.2007 5 th SECCHI Consortium Meeting: Wiegelmann et al.: SECCHI-3D reconstruction software 3D-Loops guide Data Analysis
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Orsay, 07.03.2007 5 th SECCHI Consortium Meeting: Wiegelmann et al.: SECCHI-3D reconstruction software Better Models More Challenging Computational + Observational
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