Experimental Observations of 3D Dynamics of Magnetic Flux Ropes

Laboratory plasma experiments reveal that when electric current flows along open magnetic field lines, strong unbalanced MHD forces evolve the plasma through a sequence of distinct morphologies. The forces drive flows that convect frozen-in magnetic flux associated with the magnetic field created by the electric current so the flowing plasma effectively carries its own pinching force. The result is a self-collimating, MHD-driven plasma jet. The jet kinks at a critical length determined by the Kruskal-Shafranov kink instability. The kink can spawn a localized fine-scale, much faster instability that rips the jet apart resulting in localized explosive 3D reconnection. This secondary instability has been identified as a Rayleigh-Taylor instability and has free energy coming from the effective gravity inherent in the kink-induced jet lateral acceleration. When current flows along an arched magnetic flux tube having solar corona loop morphology, MHD forces drive plasma jets from \textit{both} ends towards the apex; these jets fill the flux tube with just the right amount of plasma to maintain constant density while the flux tube volume increases as a result of hoop-force-driven major radius expansion.