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Exploring the Mysteries of Sigmoids: A Journey Through Flux and Magnetic Fields

"Sigmoid: A Twisted Tale of Flux and Fields" by Tyler Behm delves into the intriguing nature of sigmoids formed in solar physics. This study examines the components of the "S," tracing the evolution of sigmoids over time and exploring methods for their study. Through rigorous research, including NLFFF modeling and the examination of cross-sections and QSL maps, Tyler aims to find the best fit model and understand the significance of these magnetic structures. Key findings may shed light on energy boundaries, stability predictions, and the dynamics of coronal plasma.

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Exploring the Mysteries of Sigmoids: A Journey Through Flux and Magnetic Fields

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  1. Sigmoid:A Twisted Tale of Flux and Fields By Tyler Behm Mentors: Antonia Savcheva Ed DeLuca

  2. Etymology Sigm- -oid Having the shape or form of • Sigma

  3. Talk Outline Part 1: Background • What is the “S” made of? • How do sigmoids evolve with time? • How can we study sigmoids? Part 2: REU Research • Finding best fit model • Cross-sections and QSL maps

  4. What is the “S” made of? • Cooled plasma suspend by coiled magnetic fields - + - + Gold, T., and Hoyle, F., Mon. Not. R. astron. Soc, 120, 89 (1961)

  5. How do sigmoids evolve with time? • Magnetic reconnection • 68% of erupting active regions are sigmoids

  6. How can we study sigmoids? NLFFF Modeling Force-Free Sigmoid Cross- Section Lorentz Pressure Potential Linear Nonlinear

  7. Tyler’s WorkSignificance and Goals • Goals Find best fit NLFFF model in axial/polodial flux space Generate mapping of field divergence (QSL) • Significance Place boundaries on energy in field Estimate helicity; Predict stability of sigmoid Russell and Elphic, 1979

  8. Tyler’s WorkStep 1: Make Models • LOS Magnetogram Fields • XRT Images  Coronal Loops (ie Flux) • Span polodial/axial flux parameter space • Magneto-friction relaxation Both are Aug 4, 2010

  9. Tyler’s WorkStep 2: Find Best Fit 34 models to span flux parameter space Goodness = Less distance from field to flux = Green(on left charts) Unstable Unstable Aug 4, 2010

  10. Tyler’s WorkStep 3: Make Sure It’s Stable Best Fit Model Higher Flux Model Aug 4, 2010

  11. Tyler’s WorkStep 4: Make Quasi-Separatrix Layers If B-fields were heads of hair… QSL’s would be parted hairlines. QSL

  12. Tyler’s WorkStep 4: Make Quasi-Separatrix Layers Aug 4, 2010 Aug 10, 2010 Free Energy = 6.0×1031 erg Helicity = -5.2×1042 Mx2 Free Energy = 3.4×1031 erg Helicity = -2.3×1042 Mx2

  13. Tyler’s WorkStep 4: Make Quasi-Separatrix Layers Aug 4, 2010 Aug 10, 2010 Free Energy = 6.0×1031 erg Helicity = -5.2×1042 Mx2 Free Energy = 3.4×1031 erg Helicity = -2.3×1042 Mx2

  14. Conclusion What is the “S” made of? • Magnetically floated, cool coronal plasma How do sigmoids evolve with time? • Magnetic reconnection and CMEs How can we study sigmoids? • NLFFF Modeling + 1 intern = 2 sigmoids modeled tudy Me

  15. Special Thanks • NSF REU solar physics program at CfA, grant number ATM-0851866 for funding • Kathy, Marie, and all REU organizers • Antonia and Ed for excellent mentorship • Aadfor the Coronal Modeling Software • CfA for hospitality • Trae, Jonathan, andAlisdairfor computer help

  16. References Importance of Sigmoid Studies: Canfield et al. (1999, 2007) NLFFF Modeling: Savcheva, Van Ballegooijen (2009) QSL’s: Domoulin, Hénoux, Priest, Mandrini (1996) Illustrations: solarmuri.ssl.berkeley.edu/~hhudson/cartoons/

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