Numerical Simulation of Helical Jets at Active Region Peripheries

Wyper, Peter F; DeVore, C Richard; Antiochos, Spiro K

Abstract

Coronal jets are observed above minority polarity intrusions throughout the solar corona. Some of the most energetic occur on the periphery of active regions where the magnetic field is strongly inclined. These jets exhibit a non-radial propagation in the low corona as they follow the inclined field, and often have a broad, helical shape. We present a three-dimensional magnetohydrodynamic simulation of such an active-region-periphery helical jet. We consider an initially potential field with a bipolar flux distribution embedded in a highly inclined magnetic field, representative of the field nearby an active region. The flux of the minority polarity sits below a bald-patch separatrix initially. Surface motions are used to inject free energy into the closed field beneath the separatrix, forming a sigmoidal flux rope which eventually erupts producing a helical jet. We find that a null point replaces the bald patch early in the evolution and that the eruption results from a combination of magnetic breakout and an ideal kinking of the erupting flux rope. We discuss how the two mechanisms are coupled, and compare our results with previous simulations of coronal-hole jets. This comparison supports the hypothesis that the generic mechanism for all coronal jets is a coupling between breakout reconnection and an ideal instability. We further show that our results are in good qualitative and quantitative agreement with observations of active-region periphery jets.

Citation

Wyper, P. F., DeVore, C. R., & Antiochos, S. K. (2019). Numerical Simulation of Helical Jets at Active Region Peripheries. Monthly Notices of the Royal Astronomical Society, 490(3), 3679-3690. https://doi.org/10.1093/mnras/stz2674

• Journal Article Type: Article
• Acceptance Date: Sep 19, 2019
• Online Publication Date: Oct 3, 2019
• Publication Date: Dec 31, 2019
• Deposit Date: Oct 4, 2019
• Publicly Available Date: Oct 4, 2019
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 490
• Issue: 3
• Pages: 3679-3690
• DOI: https://doi.org/10.1093/mnras/stz2674
• Public URL: https://durham-repository.worktribe.com/output/1284262