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Simulations of Homologous and Cannibalistic CMEs

Simulations of Homologous and Cannibalistic CMEs. Yuhong Fan and Piyali Chatterjee High Altitude Observatory, National Center for Atmospheric Research. Cannibal CME on Nov. 4 2003 from AR 10486: fastest CME of cycle 23 . AR 10486. Zhang et al. (2008)’s study of AR 10486 :

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Simulations of Homologous and Cannibalistic CMEs

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  1. Simulations of Homologous and Cannibalistic CMEs Yuhong Fan and PiyaliChatterjee High Altitude Observatory, National Center for Atmospheric Research

  2. Cannibal CME on Nov. 4 2003 from AR 10486: fastest CME of cycle 23 AR 10486 • Zhang et al. (2008)’s study of AR 10486: • Complex delta-sunspot group with rotating sunspots (anti-clockwise) at rates ~ 1 to 4 deg/hr for period from 25 Oct – 31 Oct measured. • Vector magnetograms shows strong twisted fields. • Repeated X-class flares: X1.2 Oct.26, X17.2 Oct 28, X10 Oct 29. Movie courtesy of NASA

  3. Occurrence of homologous flares in emerging active regions with continued sunspot rotation (e.g. Gibson et al. 2002; Zhang et al. 2008; Vemareddy et al. 2012) Brown et al. (2003) Gibson et al. (2002) movie (courtesy of Sarah Gibson) showing repeated reformation of the X-ray sigmoid and “sigmoid-under-cusp” morphology in AR 8668, observation by the Yohkoh satellite.

  4. Homologous confined filament eruption via magnetic breakout (DeVore and Antiochos 2008)

  5. Model homologous eruptions in strong, highly twisted emerging active regions • Solve the ideal MHD equations in spherical wedge domain of the solar corona (2 times wider domain than that in Chatterjee and Fan 2013): • The domain is resolved by a non-uniform grid of 480x240x420 with finest resolution of ~ 1 Mm. • Initially the corona is a static isothermal atmosphere at 1MK with a pre-existing potential arcade field with a peak field strength of 70 G at the footpoints. • At the lower boundary, we impose (kinematically) a continued slow emergence of a highly twisted torus with an axial field strength of 93 G, representative of strong active region coronal field strength.

  6. ER1+ER2+ER3 ER3 ER2 ER1+ER2 ER1

  7. Summary • Continued emergence of twisted flux in strong emerging active regions can lead to homologous CMEs as a result of repeated formation of flux rope that becomes unstable to the kink and/or torus instability. • Such homologous CMEs tend to be cannibalistic, with the following CME erupting into the field opened up by the leading CME, and thus catches up and merge with the preceding one, leading to fast and more massive, highly twisted ejecta. • Homologous and Cannibalistic CMEs are a means to more effectively convert the free magnetic energy into the kinetic energy of the ejecta.

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