New Study of the Properties of the Two-scale Diffusion (Reconnection) Layer in Magnetic Reconnection Experiment

This talk reports results from recent experimental campaigns carried out on MRX (Magnetic Reconnection Experiment [1]) to measure the profiles and the dynamics of the reconnection layer by sweeping (jogging) the layer through controlled external coil currents. In those plasma jogging experiments, the reconnection layer is swept through the probe system with controlled speeds of 0.01-0.1 of the Alfven velocity. This situation is very similar to space measurements in which the current sheet moves with respect to satellites as expected in the Magnetosphere Multi-scale Satellite (MMS) mission [2]. A radial space potential well (~10-15V~2Te with respect to the inflow direction) is measured and is observed to deepen and broaden further downstream in the plasma outflow direction. The ion outflow of up to 40 km/s, about the half of the Alfven velocity, is measured [3]. The space potential profiles and the flow vectors of ions and electrons in the reconnection layers have been obtained. An extensive comparison of the experimental results with numerical simulations as well as the recent space measurements [3] is presented. [1] M. Yamada et al, Physics of Plasmas 4 (5), pp. 1936-1944, (1997) [2] J. Burch, et al, AGU Fall Meeting (2005) [3] J. Wygant et al, JGR, v.110, A09206 (2005)