3D Magnetic Reconnection in SSX: Statistical Study

We present statistical data on a large number of shots (N ≈ 1000) at SSX. The experiment generates two fully ionized relaxed MHD hydrogen plasmas which move towards each other with approximate velocity v = 30 km/s. Each plasma is enclosed in a flux conserving cylinder which makes it evolve into a twisted rope structure as it moves. The magnetic field in the reconnection region is measured with a planar 4x4 array of B-dot probes. The line averaged electron density in the center of the reconnection region is measured using Mach-Zehnder interferometry. Ion temperature is measured using ion Doppler spectroscopy. Typical SSX plasmas have B = 0.4 T , n_e = 3 × 1015 cm−3, and T_i = 10 eV . Current density is calculated in the plane of the probe array using the curl of the magnetic field. Each shot was examined for evidence of magnetic reconnection, a large density peak followed by significant ion heating as a well as oppositely directed magnetic fields around the same time. We report average n_e, T_i, and magnetic energy across observed reconnection events. Trends in the number of anti-parallel adjacient probes as well as current density around the time of the reconnection are reported. The aggregate data is compared to existing models of reconnection.