Open Issues on CME Propagation in the Inner Heliosphere

Abstract:

Over the last few years, the SECCHI imagers aboard the STEREO mission have revealed the inner heliosphere in unprecedented detail. We can image and track CMEs from their birth in the solar corona to their impact on Earth and beyond. We can routinely compare imaging observations with in-situ measurements of the same event and at the same time. It is tempting to think that the understanding the evolution of CMEs in the inner heliosphere should be straighforward. This is not the case. Although the prediction of the time of arrival of CMEs at Earth has improved somewhat, there are many outliers. Predicting the speed of the transient at Earth remain hit-or-miss. Clearly, the details of the propagation of CMEs in the inner heliosphere still elude us, preventing progress in Space Weather forecasting amongh other things.