Effects of pre-formed plasma inside a guiding cone in fast ignition scheme

Abstract

We simulated the plasma expansion of the cone wall due to the pre-pulse irradiation in fast-ignition experiments. Our radiation hydrodynamic simulations show the temporal evolution of the pre-formed plasma inside the cone. At the onset of the pre-pulse, collision within the expanding plasma near the cone axis generate a plasma jet. At the later stage of the pre-pulse the large density shelf above the critical density of 1.06 μm wavelength laser is formed near the tip inside the cone, and subsequently this critical density surface moves away from the inner surface of the cone tip. Our simulation gives roughly 80μm shift of the critical density surface under the typical pre-pulse condition of LFEX laser at Osaka University for 45 deg open angle cone. This shift of the critical density can reduce the energy coupling between the heating laser and the imploded core. © 2010 IOP Publishing Ltd.