Publications Details
Ion diode experiments on PBFA (Particle Beam Fusion Accelerator) II: Workshop on applications of high power switching
Ion diode research on Sandia National Laboratories' Particle Beam Fusion Accelerator (PBFA) II has progressed significantly during the past two years as we have operated in the shot-a-day model with well-diagnosed proton and lithium ion diode loads. During this period, we have succeeded in demonstrating efficient proton beam generation and in focusing the beam to a full width at half maximum (FWHM) spot size of 5.2 mm. Power and energy densities equivalent to 5.4 (+0.9, /minus/0.8) TW/cm/sup 2/ and 73 kJ/cm/sup 2/, respectively, on a 6 mm diameter sphere from the full diode were obtained. Tests of ion diode operation with a simple Plasma Opening Switch (POS), opening at a current of 1-2 MA, indicate efficient energy coupling and a rapid turn on of iron when the POS opens. A model of diode operation has been developed which successfully describes the operating impedance of applied-B ion diodes on PBFA II, PBFA I, Proto II, and Proto I. In addition, we have developed the capability to perform particle simulations which have helped to determine optimized insulating magnetic field profiles and anode shapes for efficient ion beam generation and focusing. Lithium ion source experiments on PBFA II have succeeded in delivering 26 kJ of lithium ions to the axis using a field-enhanced LiF ion source. Several active lithium ion sources, which should allow improved lithium began generation and focusing, are now being prepared for testing on PBFA II. 11 refs., 10 figs., 2 tabs.