Strong coronal channelling and interplanetary evolution of a solar storm up to Earth and Mars

TL;DR

This study reveals how a solar storm's non-radial propagation, influenced by coronal channelling, affects its impact on Earth and Mars, improving space weather prediction models.

Contribution

It introduces the Ellipse Evolution model to accurately describe CME shape and propagation, highlighting the importance of coronal channelling in space weather forecasting.

Findings

CME was channelled 37±10 degrees from source

In situ data confirmed non-radial CME motion

Ellipse shape model fits shock observations

Abstract

The severe geomagnetic effects of solar storms or coronal mass ejections (CMEs) are to a large degree determined by their propagation direction with respect to Earth. There is a lack of understanding of the processes that determine their non-radial propagation. Here we present a synthesis of data from seven different space missions of a fast CME, which originated in an active region near the disk centre and, hence, a significant geomagnetic impact was forecasted. However, the CME is demonstrated to be channelled during eruption into a direction + 37+/-10 degree (longitude) away from its source region, leading only to minimal geomagnetic effects. In situ observations near Earth and Mars confirm the channelled CME motion, and are consistent with an ellipse shape of the CME-driven shock provided by the new Ellipse Evolution model, presented here. The results enhance our understanding of CME propagation and shape, which can help to improve space weather forecasts.