Magnetic switchback development from the evolution of torsional Alfvén waves
Abstract
Magnetic switchbacks are mostly Alfvénic local deflections, or even reversals, of the ambient magnetic field of the solar wind. Despite intense research their origin remains unclear and is highly debated. Here we describe a new simulation study demonstrating how torsional Alfvén waves can evolve into switchbacks. We use surface rotational motions to launch torsional Alfvén waves into the super-radially expanding magnetic field of a coronal hole. The simulations demonstrate that in such an expanding wind, the waves initially steepen as they propagate while also inducing a cylindrical parallel plasma jet. A combination of shear from the jet and wave evolution under the constraint of approximate spherical polarisation (|B|≈ const.) then leads to the formation of switchbacks in a ring configuration. We explore the 3D nature of the switchbacks, how and where they from, and present scalings for their peak deflection and parallel and perpendicular length scales. We also derive an expression for switchback deflection in the linear regime which we contrast against our results. The results are discussed in relation to recent observations and previous switchback formation studies.
Related
- Spectral signatures of torsional Alfvén waves in synthetic Hα
- Radial Evolution of Near-Sun Magnetic Switchback Alfvénicity, Occurrence Rate, and Size
- Dynamics of a switchback-like magnetic deflection induced by a propagating coronal jet
- Dynamics of switchback-like magnetic deflection induced by a propagating coronal jet
- Radial increase of the compensated interplanetary magnetic field magnitude as a result of the growth of spherically polarized Alfvén waves
BibTeX
@misc{wyper2026magnetic,
title = {{Magnetic switchback development from the evolution of torsional Alfvén waves}},
author = {Peter F Wyper and Etienne Pariat and Lorenzo Matteini and Jonathan Squire and Jade Touresse},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.34518},
eprint = {2610.34518},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.34518},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Magnetic switchback development from the evolution of torsional Alfvén waves
AU - Peter F Wyper
AU - Etienne Pariat
AU - Lorenzo Matteini
AU - Jonathan Squire
AU - Jade Touresse
PY - 2026
DA - 2026/10/25
PB - arXiv
DO - 10.48550/arxiv.2610.34518
UR - https://arxiv.org/abs/2610.34518
AB - Magnetic switchbacks are mostly Alfvénic local deflections, or even reversals, of the ambient magnetic field of the solar wind. Despite intense research their origin remains unclear and is highly debated. Here we describe a new simulation study demonstrating how torsional Alfvén waves can evolve into switchbacks. We use surface rotational motions to launch torsional Alfvén waves into the super-radially expanding magnetic field of a coronal hole. The simulations demonstrate that in such an expanding wind, the waves initially steepen as they propagate while also inducing a cylindrical parallel plasma jet. A combination of shear from the jet and wave evolution under the constraint of approximate spherical polarisation (|B|≈ const.) then leads to the formation of switchbacks in a ring configuration. We explore the 3D nature of the switchbacks, how and where they from, and present scalings for their peak deflection and parallel and perpendicular length scales. We also derive an expression for switchback deflection in the linear regime which we contrast against our results. The results are discussed in relation to recent observations and previous switchback formation studies.
ER -