Ion flow and fusion reactivity characterization of a spherically convergent ion focus

accelerating potential angular momentum asymmetries beam beam-background beam-beam beam-cathode calculated cathode current cathode grid cathode radius cathode voltage Chapter cm radius collimation collisions convergence improves Convergent Ion core density core ion density core region core size Debye shielding decreasing deuterium discharge double probe edge plasma effects electrostatic potential distribution emissive probe energy estimate expected experimental Figure flow convergence fusion power fusion production rate fusion reaction rate Fusion Technol geometric grid spacing grid wires Hirsch HWHM increase indicates injected current inner grid inside the cathode ion current ion flow ion gun J. W. Robinson mantle region Maxwellian Nadler neutral pressure neutron production rate neutron rates observed particles Phys plasma potential Poisson's equation Polywell potential profile predicted probe tips proton rcat recirculation factor saturation current scaling SCIF device SCIF-type devices shown in Fig space-charge-limited system reactivity transparency trapped Vcat velocity virtual anode virtual cathode WISCIF