Plasma Interactions with the Space Environment in the Acceleration Region: Indications of CME-trailing Reconnection Regions

Abstract

Coronal mass ejections (CMEs) are sources of major geomagnetic disturbances. On 2013 May 10, a CME crossed the signal path between the MErcury Surface, Space ENvironment, GEochemistry, and Ranging ( MESSENGER ) spacecraft and Earth. Using the MESSENGER signal, characteristics of the density, velocity, and magnetic field properties of the crossing plasma were measured. An anomalously strong event occurred in the plasma trailing the CME’s passage that correlated with a wave mode conversion, indicating a potential reconnection region. We determine that the plasma following CMEs should be considered when studying how CMEs evolve in interplanetary space and the severity of their geomagnetic impact.