Computational modeling of pulsed-power-driven magnetized target fusion experiments

Abstract

Direct magnetic drive using electrical pulsed power has been considered impractically slow for traditional inertial confinement implosion of fusion targets. However, if the target contains a preheated, magnetized plasma, magnetothermal insulation may allow the near-adiabatic compression of such s target to fusion conditions on a much slower time scale. 100-MJ-class explosive flux One means of obtaining the preheated and magnerized plasma required for an MTF system is the rtcently reported "MAGO" concept [5,6]. MAGO is a unique, explosive-pulsed-power driven discharge in two cylindrical chambers joined by an annular nozzle. Joint Russian-American MAGO experiments have reported D-T neutron yields in excess of 10" from this plasma preparation stage alone, without going on to the proposed separately driven M7'F implosion of the main plasma chamber. Two-dimensional MHD computational modeling of MAGO discharges shows good agreement to experiment. The calculations suggest that after the observed neutron pulse, a diffuse 2-pinch plasma with temperature in excess of 100 eV is created, which may be suitable for subsequent MTF implosion, in a heavy liner magnetically driven by explosive pulsed power. Other MTF conctpts, such as fiber-initiated Zpinch target plasmas, are also being computationally and theoretically evaluated. The status of our modeling efforts will be reported.

The Los Alamos/Arzamas-16 collaboration on ultrahigh magnetic fields and ultrahigh energy pulsed power

“…5. The most recent experimental results, and corresponding two-dimensional computations, are reported separately in these proceedings [17,18]. The computations are in reasonable agreement With the expekental observations.…”

“…A gain of 16, and a thermonuclear yield of 1 GJ, is predicted for a density of 6.7 x 10-6 g/cm3 (the computationally predicted density achieved experimentally), a pusher implosion velocity of 2 c m l p and a maximum radial convergence of less than 20. The survey computations show that the 290 eV average temperature computed for an earlier, lesser diagnosed experiment [18] can significantly reduce the convergence required and that approximately adiabatic compression can be expected for initial magnetic fields as low as 75 Mi.…”