Rogowski Coil Array for Collisionless Magnetic Reconnection Experiments at VTF

Recent experiments on magnetic reconnection at the Versatile Toroidal Facility (VTF) indicate that the electron current may become filamented during spontaneous reconnection events [1]. A new array of Rogowski coils, which has centimeter-scale resolution, will measure the parallel currents driven by fast reconnection in the presence of a guide magnetic field. The diagnostic should confirm the filamentary structure of the current profile, determine the distribution of filaments around the X-line, and reveal when the filaments are generated with respect to the onset of reconnection. In addition, multi-shot scans performed by moving the Rogowski coil array across a poloidal section and to several different toroidal angles will yield high-resolution measurements of the reproducible features of the current profile that develops during three-dimensional reconnection at VTF. Preliminary data will be presented if available.\\[1ex] [1] J. Egedal et al., Phys. Rev. Lett., {\bf 98}, 015003 (2007)