Indirect drive ICF using highly supersonic, radiatively cooled, plasma slugs

摘要

Summary form only given. Details are presented of a new approach to indirect drive inertial confinement fusion which makes use of highly supersonic, radiatively cooled, slugs of plasma to energise a hohlraum. Such projectiles could be formed by, for example, the implosion of a conical tungsten wire array (in a similar fashion to radiatively cooled jets]) or by using a radial wire array accelerated along a coaxial plasma gun. In each case, substantial radiative cooling of the tungsten plasma at the launch point results in very high Mach numbers and low divergence. 2D resistive MHD simulations are presented which suggest that a 'Z' class machine can produce a mm sized slug of a few ns duration containing several hundred kJ of kinetic energy. This object therefore has the potential to deliver /spl sim/100 TW of kinetic flux (similar to a singly charged heavy ion beam of /spl sim/100 MA current) into a hohlraum of small dimension. Simulations of the interaction of such a plasma slug with a converter foil show efficient conversion of kinetic energy into radiation. 3D view-factor calculations of a roughly NIF-scale cylindrical hohlraum with twin converter foils are then used to establish the drive temperature and symmetry for capsule implosion experiments. The potential advantages of the system for the ignition of relatively small capsules on modest sized facilities with the potential for limited stand-off between the driver and the target are discussed.