Slowing of Magnetic Reconnection Concurrent with Weakening Plasma Inflows and Increasing Collisionality in Strongly Driven Laser-Plasma Experiments

An evolution of magnetic reconnection behavior, from fast jets to the slowing of reconnection and the establishment of a stable current sheet, has been observed in strongly driven, β ≲ 20 laser-produced plasma experiments. This process has been inferred to occur alongside a slowing of plasma inflows carrying the oppositely directed magnetic fields as well as the evolution of plasma conditions from collisionless to collisional. High-resolution proton radiography has revealed unprecedented detail of the forced interaction of magnetic fields and super-Alfvénic electron jets (V[subscript jet] ~ 20V[subscript A]) ejected from the reconnection region, indicating that two-fluid or collisionless magnetic reconnection occurs early in time. The absence of jets and the persistence of strong, stable magnetic fields at late times indicates that the reconnection process slows down, while plasma flows stagnate and plasma conditions evolve to a cooler, denser, more collisional state. These results demonstrate that powerful initial plasma flows are not sufficient to force a complete reconnection of magnetic fields, even in the strongly driven regime.United States. Dept. of Energy (Grant DE-NA0001857)University of Rochester. Laboratory for Laser Energetics (Grant 415935-G)National Laser User’s Facility (Grant DE-NA0002035)University of Rochester. Fusion Science Center (Grant 5-24431