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Context. Flux ropes in the solar wind are a key element of heliospheric dynamics and particle acceleration. When associated with current sheets, the primary formation mechanism is magnetic reconnection and flux ropes in current sheets are commonly used as tracers of the reconnection process. Aims. Whilst flux ropes associated with reconnecting current sheets in the solar wind have been reported, their occurrence, size distribution, and lifetime are not well understood. Methods. Here we present and analyse new Solar Orbiter magnetic field data reporting novel observations of a flux rope confined to a bifurcated current sheet in the solar wind. Comparative data and large-scale context is provided by Wind. Results. The Solar Orbiter observations reveal that the flux rope, which does not span the current sheet, is of ion scale, and in a reconnection formation scenario, existed for a prolonged period of time as it was carried out in the reconnection exhaust. Wind is also found to have observed clear signatures of reconnection at what may be the same current sheet, thus demonstrating that reconnection signatures can be found separated by as much as ∼2000 Earth radii, or 0.08 au. Conclusions. The Solar Orbiter observations provide new insight into the hierarchy of scales on which flux ropes can form, and show that they exist down to the ion scale in the solar wind. The context provided by Wind extends the spatial scale over which reconnection signatures have been found at solar wind current sheets. The data suggest the local orientations of the current sheet at Solar Orbiter and Wind are rotated relative to each other, unlike reconnection observed at smaller separations; the implications of this are discussed with reference to patchy vs. continuous reconnection scenarios.
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This content will become publicly available on June 21, 2026
Parametric Regimes of Thin Current Sheets in Planetary Magnetospheres and Solar Wind
Abstract Current sheets are quasi‐1D layers of strong current density, which play a crucial role in storing magnetic field energy and subsequently releasing it through charged particle acceleration and plasma heating. They are observed in planetary magnetospheres and solar wind flows, where they are also known as solar wind discontinuities. Despite significant variations in plasma parameters across different magnetospheres and the solar wind, current sheet configurations can remain fundamentally similar. In this study, we analyze current sheets observed in various regions, including the near‐Earth (within 30 Earth radii) and distant (50–200 Earth radii) magnetotail, Earth's dayside and nightside magnetosheath, the near‐Earth solar wind, and Martian and Jovian magnetotails. We examine three key plasma parameters: the plasma beta (ratio of plasma to magnetic pressure), the Alfvénic Mach number (ratio of plasma bulk flow speed to Alfvén speed in the current sheet reference frame), and the ion to electron temperature ratio. Additionally, we investigate the kinetic, thermal, and magnetic field energy densities. Our cross‐system analysis demonstrates that the same current sheet configuration can exist across a very wide parametric space spanning multiple orders of magnitude. We also highlight the distinct plasma environments of the Martian and Jovian magnetotails, characterized by large populations of heavy ions, emphasizing their significance in comparative magnetospheric studies.
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- Award ID(s):
- 2400336
- PAR ID:
- 10614353
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Journal of Geophysical Research: Space Physics
- Volume:
- 130
- Issue:
- 6
- ISSN:
- 2169-9380
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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