Axial flows in expanding arched, plasma-filled flux tubes

Magnetic flux tubes are significant features in a diverse array of plasma systems, including fusion devices and solar and astrophysical environments. Laboratory experiments are a valuable tool for elucidating the fundamental physics of these structures. Highly dynamic, individual arched flux tubes were created with a magnetized plasma gun and studied with a variety of diagnostics (magnetic probes, dual-gas techniques, spectroscopy, etc.). Bulk flows were found to carry plasma into a flux tube from both footpoints, keeping the density high even as the major radius increased significantly and the axis underwent a kink instability. A pair of complementary MHD models provides a quantitative description of the evolution.