Experimental multiple-scale investigation of guide-field reconnection dynamics

The dynamics of magnetic reconnection on temporal and spatial scales ranging from the global boundary conditions down to microscopic dynamics are experimentally investigated in the linear, guide-field reconnection experiment Vineta.II. On the global scale, the reconnection current driven by the varying magnetic fields is well described by an inductive electrical circuit, limiting the reconnection rate by the external geometry of the current path. A current sheet forms that has a three-dimensional structure due to the magnetic X-point topology together with a non-equilibrium pressure that lead to both a distortion and expansion of the current sheet along the experiment axis. As a consequence, a three-dimensional distribution of the local flux transfer rate along the current sheet is observed. On the microscopic scale, high frequency whistler-like magnetic fluctuations are observed that are localized within the current sheet and which display properties of the lower hybrid drift instability. (paper)