Liner velocity, current, and symmetry measurements on the 32 megamp flux compression generator experiment ALT-1

A flux compression generator pulse power system, designed, built and fielded by a Russian team at the All Russian Scientific Research Institute of Experimental Physics (VNIIEF), was used to successfully drive an aluminum liner to velocities greater than 12 km/sec. The experiment objective was to demonstrate performance of a precision liner implosion at an Atlas current of 30 MA or greater. Diagnostics to measure liner performance were an essential part of the experiment. An experimental team from Los Alamos National Laboratory (LANL) provided a suite of diagnostics to measure liner performance. Three diagnostics were fielded: (1) a velocity interferometer (VISAR) to continuously measure the liner inner-surface velocity throughout the entire range of travel; (2) two Faraday rotation devices to measure liner current during the implosion; and (3) sixteen fiber optic impact pins to record liner impact time and provide axial and azimuthal symmetry information. All diagnostics performed very well. Major results are maximum current: 32.3 MA, velocity at impact: greater than 12 km/s, symmetry: the impact pins indicated that the liner was smooth, solid and axially symmetric upon arrival at the diagnostic package. The LANL team fabricated, installed and recorded the three diagnostics presented here. All necessary equipment was brought to the site in Russia. The VNIIEF team fielded other diagnostics to measure machine performance.