Tapping the Core - a study of Alfvénic energy flow in an erupting flux-rope configuration

We analyze the evolution of reconnecting magnetic field in a 3-D numerical simulation of a partially-ejected solar flux rope, with a focus on understanding how the flux rope dynamics is linked to the flow of energy through the field and the solar atmosphere as Alfvénic Poynting flux. The magnetic flux rope splits in two during its eruption, with reconnection taking place between the erupting rope and surrounding fields, and internally in the strong field of the rope. We track the Poynting flux entering and leaving the simulation current sheets, and by mapping this down to the solar surface we identify locations of weak and strong energy deposition in the lower atmosphere. Our tracking method enables us to link the lower atmosphere signatures to different stages of the coronal reconnection. We find a predominantly two-ribbon morphology in the locations of Poynting flux deposition in the lower atmosphere, in which the transition from reconnection involving weaker field external to the flux rope, to reconnection involving the flux rope core field, is accompanied by rapid ribbon spreading. In the core-field reconnection phase, ribbons move into strong field regions on the solar surface, and locations of highly concentrated downward-directed Poynting flux are found, which may be linked to the most energetic flare `footpoints' seen in optical and hard X-ray emission.