Solar physics: Towards better predicting of geomagnetic storms

The channelling of solar storms by the Sun’s magnetic field influences their direction and therefore their potential to generate severe disturbances on Earth, reports a study published online in Nature Communications. This explains why a coronal mass ejection (CME) in January 2014 missed the Earth and may allow for better modelling and forecasting of disruptive solar storms in future.

CMEs where a mass of the order of 1012 (a trillion) kilogrammes is ejected from the Sun, can lead to massive disturbances on Earth, including power blackouts and satellite failures. Policy makers have increasingly recognised them as a serious natural hazard and producing reliable real-time predictions of their effects is therefore essential. Although the disturbances on Earth are often related to the CME’s source position on the Sun’s surface, a model that can produce reliable space weather forecasts remains unavailable.

Christian Mostl and colleagues collected data from 7 different space missions on a CME event dated 7th January 2014. The event resulted in a very fast CME, which erupted from an active solar region facing the Earth. For this reason strong negative effects were forecast; however, the worst of the storm missed the Earth and no geomagnetic disturbances followed.

The authors used the data from the missions to model the CME’s evolution from the Sun, up to the Earth, and as far as Mars where it was detected by the Curiosity rover. From their model, the authors can now report that the CME was channelled in a longitudinal direction by the Sun’s magnetic fields. Further space missions will provide increasing understanding of solar storms propagations, providing the chance for increasingly reliable space weather forecasts - essential to gauge the impact of these massive events on planets and spacecraft.