Reconnection remnants in the magnetic cloud of October 18-19, 1995: A shock, monochromatic wave, heat flux dropout, and energetic ion beam

Evidence is presented that the Wind spacecraft observed particle and field signatures on October 18-19, 1995, due to reconnection near the foot points of a magnetic cloud (i.e., between 1 and 5 solar radii). These signatures include (1) an internal shock traveling approximately along the axis of the magnetic cloud, (2) a simple compression of the magnetic field consistent with the foot point magnetic fields being thrust outward at speeds much greater than the solar wind speed, (3) an electron heat flux dropout. occurring within minutes of the shock, indicating a topological change resulting from disconnection from the solar surface, (4) a very cold 5 keV proton beam, and (5) an associated monochromatic wave. We expect that given observations of enough magnetic clouds, Wind and other spacecraft will see signatures similar to the ones reported here indicating reconnection. However, these observations require the spacecraft to be fortuitously positioned to observe the passing shock and other signatures and will therefore be associated with only a small fraction of magnetic clouds. Consistent with this, a few magnetic clouds observed by Wind have been found to possess internal shock waves.