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On Magnetic Configuration of Solar Sources for Erupting CMEs: Case Study

This study analyzes the magnetic field structure and evolution of solar sources associated with eruptive events, using high-resolution vector magnetic field measurements. The data helps determine the orientation of presumed flux ropes in the events.

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On Magnetic Configuration of Solar Sources for Erupting CMEs: Case Study

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  1. On Magnetic Configuration of Solar Sources for Erupting CMEs: Case Study Yang Liu Stanford University

  2. Motivation • Magnetic configuration of solar sources for CMEs may determine the property of magnetic field in their counterparts at 1 AU, and further help predict geoeffectiveness. • HMI takes full-disk vector magnetic field measurements with high-spatial and temporal resolution and continuous data coverage. This observation provides unique opportunity to study magnetic field configuration and evolution of the solar sources. • This study presents preliminary analyses of magnetic field structure of the solar sources for the eruptive events listed in Savani et al (2015). It provides data necessary to help determine the orientation of the presumed flux ropes in the events.

  3. Case Study: Savani’s D Images from SOHO/LASCO halo CME catalog: A halo CME that was associated with a M1.9 flare from AR 11504.

  4. Case Study: Savani’s D The active region AR 11504 produced the M1.9 flare.Play flare movie

  5. Case Study: Savani’s D Magnetic field configuration and the Case D. Top: synoptic chart of magnetic field. Middle: footpoints of coronal holes at the solar surface (dots), and the current sheets (black solid curves); Bottom: coronal holes maps up to the source surface. • The active region was at southern hemisphere; • The active region was sitting near a coronal hole.

  6. Case Study: Savani’s D Evolution of magnetic field in AR 11504 (Bz movie from HMI vector field data)

  7. Case Study: Savani’s D Vector magnetic field in AR 11504 measured by HMI.

  8. Case Study: Savani’s D With time series vector magnetic field data, we can calculate (1) helicity flux injection rate through the photosphere, and (2) a force-free alpha, a proxy of magnetic twist.

  9. Case Study: Savani’s D • Sigmoid: S-shape (or forward S), implying a positive (right-handed) helicity.

  10. Summary of Savani’s Case D

  11. Summary of Savani’s Cases • Magnetic twist in all cases follows the hemisphere rule; • Most of cases have the same sign of twist and helicity flux; • For most cases, the signs of twist, helicity flux, and sigmoid are consistent.

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