Laboratory Magnetic Reconnection Experiments with Colliding, Magnetized Laser-Produced Plasma Plumes

Thursday, 18 December 2014: 3:28 PM
William R Fox II1, Amitava Bhattacharjee1, Wenjun Deng1, Clément Moissard2, Kai Germaschewski3, Gennady Fiksel4, Daniel Barnak4, Po-Yu Chang4, Suxing Hu4 and Philip Nilson4, (1)Princeton Plasma Physics Laboratory, Princeton, NJ, United States, (2)Ecole Normale Supérieure Paris, Paris, France, (3)University of New Hampshire Main Campus, Durham, NH, United States, (4)University of Rochester, Laboratory for Laser Energetics, Rochester, NY, United States
We present results from experiments and simulations of magnetic reconnection between colliding plumes of laser-produced plasma. In the experiments, which open up a new experimental regime for reconnection study, bubbles of high-temperature, high-density plasma are created by focusing lasers down to sub-millimeter-scale spots on a plastic or metal foil, ionizing the foil into hemispherical bubbles that expand supersonically off the surface of the foil. If multiple bubbles are created at small separation, the bubbles expand into one another, and the embedded magnetic fields (either self-generated or externally imposed) are squeezed together and reconnect. We will review recent experiments, which have observed magnetic field annihilation, outflow jets, particle energization, and the formation of elongated current sheets. We compare the results against experiments with unmagnetized plumes, which observe the Weibel instability as the two plumes collide and interact. Particle-in-cell simulations of the strongly driven reconnection in these experiments show fast reconnection due to two-fluid effects, flux pile-up, and plasmoid formation, and show particle energization by reconnection.