Authors: S. K. Antiochos (U Michigan), C. R. DeVore (NASA/GSFC), K. J. Knizhnik (NRL), L. K. S. Daldorff (NASA/GSFC), P. W. Schuck (NASA/GSFC)

Explosive solar activity ranging from giant CMEs/eruptive flares with scales > 10¹⁰ cm to tiny coronal hole jets with scales < 10⁸ cm, are all believed to be due to the release of the magnetic free energy stored in a filament channel. Consequently, understanding why and how filament channels form is critical for understanding the origins of space weather at the Sun and predicting its effects at Earth. Filament channels have two key properties:  they are ubiquitous, eventually appearing over every long-lived polarity-inversion-line (PIL) on the photosphere, even reappearing after an ejection, and they strongly obey the hemispheric helicity preference, negative in the North and positive in the South. In Antiochos (2013) we proposed the helicity condensation model for filament channel formation. The gist of the model is that a net helicity is injected into the corona in each hemisphere by the convective flows and then turbulent-like reconnection in the corona results in the helicity showing up as magnetic shear localized along PILs. We present recent numerical simulations of the model exploring the effect of multi-scale driving. We discuss the implications of these results for filament channel observations, especially for possible coronal magnetic field measurements by DKIST. The primary conclusions from our work are that the helicity condensation model is robust and that understanding the effects of magnetic helicity conservation is absolutely essential for advancing our understanding of explosive solar activity.

This work was supported by the ISFM program at NASA/GSFC and LWS grants to U Michigan.