Hydrodynamic simulation code for target implosion including shock waves and calculated target gain irradiated by ion beams

Abstract

In the process of target implosion, usually shock waves appear in the fuel layer and have a large influence on fuel compression. So far the one‐dimensional hydrodynamic code, by which the implosion process of the target was simulated, included an artificial viscosity which was so large in comparison with the real viscosity that the shock layer spreads over one mesh width of the space in the simulation. As a result, the calculated ion temperature, fusion parameters, etc., and hence, the target gain include some errors. A new calculation scheme which treats shock waves in the fuel layer as discontinuous surfaces is proposed here instead of introducing the artificial viscosity.The code is applied to targets irradiated by ion beams. The target is a cryogenic hollow shell which consists of three layer of lead, aluminum and deuterium‐tritium fuel. For a proton beam, a search is made for the optimum values of the fuel mass, the rate of energy deposition in the Al layer, the particle energy, the target radius and the beam energy. The particle energy of 4 MeV is optimum for the proton beam. For the lithium beam and the lead beam, the optimum particle energies are obtained to be 20‐30 MeV and 3 GeV, respectively.