Multispacecraft Remote Sensing and In Situ Observations of the 2020 November 29 Coronal Mass Ejection and Associated Shock: From Solar Source to Heliospheric Impacts

TL;DR

This study combines remote sensing and in situ data from multiple spacecraft to analyze the 2020 November 29 CME and shock, revealing their structure, expansion, and heliospheric impacts from the Sun to Earth.

Contribution

It provides a comprehensive multi-spacecraft analysis of the CME and shock, integrating modeling and observations to better understand their propagation and impacts.

Findings

The shock has an ellipsoidal structure expanding in all directions.

The CME and shock reach Parker Solar Probe and STEREO A.

The far flank of the CME arrives at Earth without shock signature.

Abstract

We investigate the source eruption, propagation and expansion characteristics, and heliospheric impacts of the 2020 November 29 coronal mass ejection (CME) and associated shock, using remote sensing and in situ observations from multiple spacecraft. A potential--field source--surface model is employed to examine the coronal magnetic fields surrounding the source region. The CME and associated shock are tracked from the early stage to the outer corona using extreme ultraviolet and white light observations. Forward models are applied to determine the structures and kinematics of the CME and the shock near the Sun. The shock shows an ellipsoidal structure, expands in all directions, and encloses the whole Sun as viewed from both SOHO and STEREO A, which results from the large expansion of the CME flux rope and its fast acceleration. The structure and potential impacts of the shock are mainly determined by its radial and lateral expansions. The CME and shock arrive at Parker Solar Probe and STEREO A. Only based on the remote sensing observations, it is difficult to predict whether and when the CME/shock would arrive at the Earth. Combining Wind in situ measurements and WSA-ENLIL simulation results, we confirm that the far flank of the CME (or the CME leg) arrives at the Earth with no shock signature. These results highlight the importance of multipoint remote sensing and in situ observations for determining the heliospheric impacts of CMEs.