Solar origins of a strong stealth CME detected by Solar Orbiter

TL;DR

This study traces the origin of a stealth CME to a quiet Sun cavity using advanced imaging and magnetic field models, revealing its strong in situ magnetic field despite a weak source region.

Contribution

It identifies the source region of a stealth CME and links in situ magnetic measurements to the remote sensing observations, enhancing understanding of such elusive events.

Findings

Stealth CME originated from a quiet Sun cavity in the northern hemisphere.

The CME exhibited a strong magnetic field in situ despite weak source magnetic fields.

Interaction with the environment likely increased the magnetic field strength measured in situ.

Abstract

Aims.We aim to locate the origin of a stealth coronal mass ejection (CME) detected in situ by the MAG instrument on board Solar Orbiter, and make connections between the CME observed at the Sun, and the interplanetary CME (ICME) measured in situ. Methods. Remote sensing data are analysed using advanced image processing techniques to identify the source region of the stealth CME, and the global magnetic field at the time of the eruption is examined using Potential Field Source Surface (PFSS) models. The observations of the stealth CME at the Sun are compared with the magnetic field measured by the Solar Orbiter spacecraft, and plasma properties measured by the Wind spacecraft. Results. The source of the CME is found to be a quiet Sun cavity in the northern hemisphere. We find that the stealth CME has a strong magnetic field in situ, despite originating from a quiet Sun region with an extremely weak magnetic field. Conclusions. The interaction of the ICME with its surrounding environment is the likely cause of a higher magnetic field strength measured in situ. Stealth CMEs require multi-wavelength and multi-viewpoint observations in order to confidently locate the source region, however their elusive signatures still pose many problems for space weather forecasting. The findings have implications for Solar Orbiter observing sequences with instruments such as EUI that are designed to capture stealth CMEs