Pulsed-Power Driven Magnetic Reconnection within an Externally-Generated Field

We present results from the first experimental campaign to study pulsed-power driven magnetic reconnection in the presence of a strong magnetic guide field. On the MAIZE facility (450 kA, 240 ns rise time) we surrounded a dual exploding wire array load with an externally-powered Helmholtz coil to provide the guide field (0-2 T). A reconnection layer is formed from the interaction of oppositely-directed magnetic fields (~1-2 T) advected by carbon plasma flows moving at (~50 km/s). Line-integrated electron density measurements of the reconnection layer were made with spatially-resolved laser interferometry (1064 nm). The plasma dynamics were observed with both an optical fast-framing camera and a four-frame XUV MCP detector. B-dot probes were fielded to measure the advected magnetic field. Our results indicate that the external field significantly affects the dynamics of the inflowing plasma streams and reconnection layer produced, broadening the layer with increasing external field. At strong guide fields (2 T), we observe a void instead of a layer, suggesting the externally-applied field is frozen-out of the ablation flows and compressed until the incoming flows stagnate against the magnetic pressure.