The eruption of a magnetic flux rope observed by \textit{Solar Orbiter} and \textit{Parker Solar Probe}

TL;DR

This study combines remote sensing and in-situ measurements from Solar Orbiter and Parker Solar Probe to observe the formation, evolution, and eruption of a magnetic flux rope, revealing its handedness, structure, and dynamics.

Contribution

It presents the first combined remote sensing and in-situ observations of a flux rope's eruption and evolution near the Sun, including plasma flow analysis and flux rope diagnostics.

Findings

Helical plasma flows indicate a right-handed flux rope with positive chirality.

Flux rope length and velocity increased before eruption.

In-situ data supports the flux rope's right-handed structure during eruption.

Abstract

Magnetic flux ropes are a key component of coronal mass ejections, forming the core of these eruptive phenomena. However, determining whether a flux rope is present prior to eruption onset and, if so, the rope's handedness and the number of turns that any helical field lines make is difficult without magnetic field modelling or in-situ detection of the flux rope. We present two distinct observations of plasma flows along a filament channel on 4 and 5 September 2022 made using the \textit{Solar Orbiter} spacecraft. Each plasma flow exhibited helical motions in a right-handed sense as the plasma moved from the source active region across the solar disk to the quiet Sun, suggesting that the magnetic configuration of the filament channel contains a flux rope with positive chirality and at least one turn. The length and velocity of the plasma flow increased from the first to the second observation, suggesting evolution of the flux rope, with the flux rope subsequently erupting within $\sim$5~hours of the second plasma flow. The erupting flux rope then passed over the \textit{Parker Solar Probe} spacecraft during its Encounter 13, enabling \textit{in-situ} diagnostics of the structure. Although complex and consistent with the flux rope erupting from underneath the heliospheric current sheet, the \textit{in-situ} measurements support the inference of a right-handed flux rope from remote-sensing observations. These observations provide a unique insight into the eruption and evolution of a magnetic flux rope near the Sun.