The Build-up to Eruptive Solar Events Viewed as the Development of Chiral Systems
Martin, Sara F.
Pevtsov, Alexei A.
2nd ATST-EAST Workshop in Solar Physics: Magnetic Fields from the Photosphere to the Corona (Astronomical Society of the Pacific Conference Series)
Astronomical Society of the Pacific
When we examine the chirality or observed handedness of the chromospheric and coronal structures involved in the long-term build-up to eruptive events, we find that they evolve in very specific ways to form two and only two sets of large-scale chiral systems. Each system contains spatially separated components with both signs of chirality, the upper portion having negative (positive) chirality and the lower part possessing positive (negative) chirality. The components within a system are a filament channel (represented partially by sets of chromospheric fibrils), a filament (if present), a filament cavity, sometimes a sigmoid, and always an overlying arcade of coronal loops. When we view these components as parts of large-scale chiral systems, we more clearly see that it is not the individual components of chiral systems that erupt but rather it is the approximate upper parts of an entire evolving chiral system that erupts. We illustrate the typical pattern of build-up to eruptive solar events first without and then including the chirality in each stage of the build-up. We argue that a complete chiral system has one sign of handedness above the filament spine and the opposite handedness in the barbs and filament channel below the filament spine. If the spine has handedness, the observations favor its having the handedness of the filament cavity and coronal loops above. As the separate components of a chiral system form, we show that the system appears to maintain a balance of right-handed and left-handed features, thus preserving an initial near-zero net helicity. Each individual chiral system may produce many successive eruptive events above a single filament channel.
National Solar Observatory (NSO)
AURA Inc., under cooperative agreement with the National Science Foundation (NSF).
European Union Seventh Framework Programme (FP7/2007-2013) - COronal Mass Ejections and Solar Energetic Particles (COMESEP) project
Copyright © Copyright 2012 Astronomical Society of the Pacific
Vol. 463, pp. 157-174