Optimum particle range for triggering fast ignition

Abstract
An analytic model for the dynamics of fast ignition is developed for the case in which the particle beam heats the fuel by generating a supersonic heat wave. It shows that the beam energy and intensity required for ignition increase with the particle range R. These results, together with previous ones for the subsonic regime of heating, allow for the determination of an optimum particle range value (R≈0.25 g/cm2). By decreasing the range below this value the ignition energy no longer decreases.