Comparison of magnetic energy and helicity in coronal jet simulations
Pariat, E.; Wyper, P.F.; Linan, L.
Dr Peter Wyper email@example.com
Context. While non-potential (free) magnetic energy is a necessary element of any active phenomenon in the solar corona, its role as a marker of the trigger of the eruptive process remains elusive. Meanwhile, recent analyses of numerical simulations of solar active events have shown that quantities based on relative magnetic helicity could highlight the eruptive nature of solar magnetic systems. Aims. Based on the unique decomposition of the magnetic field into potential and non-potential components, magnetic energy and helicity can also both be uniquely decomposed into two quantities. Using two 3D magnetohydrodynamics parametric simulations of a configuration that can produce coronal jets, we compare the dynamics of the magnetic energies and of the relative magnetic helicities. Methods. Both simulations share the same initial setup and line-tied bottom-boundary driving profile. However, they differ by the duration of the forcing. In one simulation, the system is driven sufficiently so that a point of no return is passed and the system induces the generation of a helical jet. The generation of the jet is, however, markedly delayed after the end of the driving phase; a relatively long phase of lower-intensity reconnection takes place before the jet is eventually induced. In the other reference simulation, the system is driven during a shorter time, and no jet is produced. Results. As expected, we observe that the jet-producing simulation contains a higher value of non-potential energy and non-potential helicity compared to the non-eruptive system. Focussing on the phase between the end of the driving-phase and the jet generation, we note that magnetic energies remain relatively constant, while magnetic helicities have a noticeable evolution. During this post-driving phase, the ratio of the non-potential to total magnetic energy very slightly decreases while the helicity eruptivity index, which is the ratio of the non-potential helicity to the total relative magnetic helicity, significantly increases. The jet is generated when the system is at the highest value of this helicity eruptivity index. This proxy critically decreases during the jet-generation phase. The free energy also decreases but does not present any peak when the jet is being generated. Conclusions. Our study further strengthens the importance of helicities, and in particular of the helicity eruptivity index, to understand the trigger mechanism of solar eruptive events.
Pariat, E., Wyper, P., & Linan, L. (2023). Comparison of magnetic energy and helicity in coronal jet simulations. Astronomy & Astrophysics, 669, Article A33. https://doi.org/10.1051/0004-6361/202245142
|Journal Article Type||Article|
|Acceptance Date||Nov 13, 2022|
|Online Publication Date||Jan 3, 2023|
|Deposit Date||Jan 9, 2023|
|Publicly Available Date||Jan 10, 2023|
|Journal||Astronomy and astrophysics.|
|Peer Reviewed||Peer Reviewed|
Published Journal Article
Publisher Licence URL
© The Authors 2023. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
You might also like
Interchange reconnection dynamics in a solar coronal pseudo-streamer
Plasmoids, Flows, and Jets during Magnetic Reconnection in a Failed Solar Eruption
The Imprint of Intermittent Interchange Reconnection on the Solar Wind
An exact threshold for separator bifurcation
The Dynamic Structure of Coronal Hole Boundaries