The Role of Reconnection in the Formation of Flux Ropes in the Solar Wind

Abstract

New magnetic loops formed in the corona beneath coronal mass ejections, CMEs, provide strong evidence that magnetic reconnection commonly occurs within the magnetic `legs' of the departing CMEs. Such reconnection is inherently 3-dimensional and produces a magnetic flux rope structure within a CME. Depending upon how far reconnection proceeds, the resulting flux rope can contain a mixture of doubly attached (to the Sun), singly attached (i.e., open), and disconnected magnetic field lines. The helicity associated with these flux ropes can be the result of emergence of helicity from beneath the solar surface or can be a consequence of photospheric motions, but the actual helical field lines observed in the solar wind in this scenario are a consequence of reconnection following eruption of the CMEs. A wide variety of solar and solar wind observations are consistent with this picture; however, it is also possible that some flux ropes, or portions thereof, observed in the solar wind emerge as such from beneath the solar surface or form from reconnection in the solar atmosphere prior to CME eruption.