Evolution and Distribution of Current Helicity in Full-Sun Simulations

Abstract

Current helicity quantifies the location of twisted and sheared non-potential structures in a magnetic field. We simulate the evolution of magnetic fields in the solar atmosphere in response to flux emergence and shearing by photospheric motions. In our global-scale simulation over many solar rotations the latitudinal distribution of current helicity develops a clear statistical pattern, matching the observed hemispheric sign at active latitudes. In agreement with observations there is significant scatter and intermixing of both signs of helicity, where we find local values of current helicity density that are much higher than those predicted by linear force-free extrapolations. Forthcoming full-disk vector magnetograms from Solar Dynamics Observatory will provide an ideal opportunity to test our theoretical results on the evolution and distribution of current helicity, both globally and in single active regions.

4 pages, 3 figures, accepted for publication in ApJ Letters

References in corpus (6)

• Doubly Helical Coronal Ejections from Dynamos and their Role in Sustaining the Solar Cycle
• Modelling the Global Solar Corona: Filament Chirality Observations and Surface Simulations
• Modelling the Global Solar Corona II: Coronal Evolution and Filament Chirality Comparison
• Magnetic Helicity Evolution During the Solar Activity Cycle: Observations and Dynamo Theory
• Helicity Observation of Weak and Strong Fields
• The distribution of current helicity at the solar surface at the beginning of the solar cycle

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