In situ multi-spacecraft and remote imaging observations of the first CME detected by Solar Orbiter and BepiColombo

Abstract

On 2020 April 19 a coronal mass ejection (CME) was detected in situ by Solar Orbiter at a heliocentric distance of about 0.8 AU. The CME was later observed in situ on April 20th by the Wind and BepiColombo spacecraft whilst BepiColombo was located very close to Earth. This CME presents a good opportunity for a triple radial alignment study, as the spacecraft were separated by less than 5${}^{\circ }$ in longitude. The source of the CME, which was launched on April 15th, was an almost entirely isolated streamer blowout. STEREO-A observed the event remotely from -75.1${}^{\circ }$ longitude, which is an exceptionally well suited viewpoint for heliospheric imaging of an Earth directed CME. The configuration of the four spacecraft has provided an exceptionally clean link between remote imaging and in situ observations of the CME. We have used the in situ observations of the CME at Solar Orbiter, Wind, and BepiColombo, and the remote observations of the CME at STEREO-A in combination with flux rope models to determine the global shape of the CME and its evolution as it propagated through the inner heliosphere. A clear flattening of the CME cross-section has been observed by STEREO-A, and further confirmed by comparing profiles of the flux rope models to the in situ data, where the distorted flux rope cross-section qualitatively agrees most with in situ observations of the magnetic field at Solar Orbiter. Comparing in situ observations of the magnetic field between spacecraft, we find that the dependence of the maximum (mean) magnetic field strength decreases with heliocentric distance as $r^{-1.24\pm 0.50}$ ($r^{-1.12\pm 0.14}$), in disagreement with previous studies. Further assessment of the axial and poloidal magnetic field strength dependencies suggests that the expansion of the CME is likely neither self-similar nor cylindrically symmetric.

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Cited by in corpus (18)

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• Multi point analysis of coronal mass ejection flux ropes using combined data from Solar Orbiter, BepiColombo and Wind
• On the Mesoscale Structure of CMEs at Mercury's Orbit: BepiColombo and Parker Solar Probe Observations
• Multi-spacecraft observations of the structure of the sheath of an interplanetary coronal mass ejection and related energetic ion enhancement
• A Coronal Mass Ejection and Magnetic Ejecta Observed In Situ by STEREO-A and Wind at 55${}^{\circ }$ Angular Separation
• Causes and Consequences of Magnetic Complexity Changes within Interplanetary Coronal Mass Ejections: a Statistical Study
• Coronal mass ejection deformation at 0.1 au observed by WISPR
• Direct First PSP Observation of the Interaction of Two Successive Interplanetary Coronal Mass Ejections in November 2020
• Parker Solar Probe Observations of Helical Structures as Boundaries for Energetic Particles
• Multi-Spacecraft Observations of the Evolution of Interplanetary Coronal Mass Ejections Between 0.3 and 2.2 AU: Conjunctions with the Juno Spacecraft
• Cross helicity of interplanetary coronal mass ejections at 1 au
• Eruption and propagation of twisted flux ropes from the base of the solar corona to 1 au
• Evolution of the Radial Size and Expansion of Coronal Mass Ejections Investigated by Combining Remote and In-Situ Observations
• Writhed Analytical Magnetic Flux Rope Model
• A coronal mass ejection encountered by four spacecraft within 1 au from the Sun: Ensemble modelling of propagation and magnetic structure
• On the specific energy and pressure in near-Earth magnetic clouds
• Magnetic Structure and Propagation of Two Interacting CMEs from the Sun to Saturn