Determine the global sector-boundary topology of the observed reconnection event

Determine the global sector-boundary topology of the 2017 November 10 solar-wind excursion observed by Magnetospheric Multiscale, including whether it represents a complete or partial crossing of the heliospheric current-sheet sector boundary.

Background

The paper analyzes a reconnection exhaust observed by the four Magnetospheric Multiscale spacecraft in the pristine solar wind on 2017 November 10. Although the reconnecting magnetic component reverses transiently across the exhaust and then returns, the external magnetic fields do not show a completed sector-polarity crossing.

Suprathermal-electron observations had identified the excursion as two partial crossings of the heliospheric current sheet, but the magnetic-field record alone does not establish the event’s global sector-boundary topology. The authors explicitly leave that classification unresolved because it is not needed for the timing and thickness measurements reported in the paper.

References

We therefore leave its global sector-boundary topology open; the timing and thickness results below do not depend on that classification.

— Direct Four-Spacecraft Measurement of Reconnection Exhaust Thickness in the Solar Wind  (2609.03088 - Chettri et al., 2 Sep 2026) in Section 2, “Event and Data”