A Coronal Hole's Effects on CME Shock Morphology in the Inner Heliosphere

TL;DR

This study investigates how a coronal hole influences the shape and expansion of a CME-driven shock in the inner heliosphere using STEREO imagery and in situ data, revealing asymmetric shock morphology related to the coronal hole's presence.

Contribution

It provides new insights into the impact of coronal holes on CME shock morphology and compares imaging-based inferences with in situ measurements at 1 AU.

Findings

CME ejecta is deflected away from the coronal hole.

Shock expands into the fast outflow from the coronal hole.

Shock normal directions from in situ data match imaging inferences.

Abstract

We use STEREO imagery to study the morphology of a shock driven by a fast coronal mass ejection (CME) launched from the Sun on 2011 March 7. The source region of the CME is located just to the east of a coronal hole. The CME ejecta is deflected away from the hole, in contrast with the shock, which readily expands into the fast outflow from the coronal hole. The result is a CME with ejecta not well centered within the shock surrounding it. The shock shape inferred from the imaging is compared with in situ data at 1 AU, where the shock is observed near Earth by the Wind spacecraft, and at STEREO-A. Shock normals computed from the in situ data are consistent with the shock morphology inferred from imaging.