Effects of different strapping field profiles on plasma loop expansion

The hoop force causes arched, current-carrying plasma loops to expand unless additional forces are applied. This expansion was slowed and even inhibited by a magnetic field of proper polarity in previous solar coronal loop experiments [1] but there was no attempt to reproduce the slow expansion to fast eruption behavior often exhibited by solar loops. The transition from a slow expansion to a fast eruption is predicted to depend on the strapping field altitude decay profile [2] which is sensitive to the planar distance to the source of the strapping field [3]. The coils are mounted on 3 axis adjustable stands that provide precision placement of the coil relative to the plasma. Preliminary data on the interaction between the plasma and specified strapping field profiles will be presented. \\[4pt] [1] J. F. Hansen and P. M. Bellan, Astrophys. J. Lett. \textbf{563}, L183 (2001)\\[0pt] [2] B. Kleim and T. Torok, Phys. Rev. Lett. \textbf{96}, 255002 (2006)\\[0pt] [3] Y. Wang and J. Zhang, ApJ \textbf{665}, 1428 (2007)