Feasibility of shock-volume ignition approach in simple spherical targets driven by heavy ion beams

Abstract

In this research, the new concept of the shock-volume ignition is proposed and then evaluated numerically by using a one-dimensional hydrodynamic code. The proposed model shows that it is possible to achieve higher energy gain with lower input energy inside the volume ignition framework by separating the compression and ignition stages as applied in the standard shock-ignition method. The current study intends to examine the optimum pulse shaping mode, the ignition conditions, and the physical aspects of the target performance in this new proposal for the typical simple spherical target designed previously for volume ignition studies driven by heavy-ion beams. Accordingly, a simple one-step pulse was replaced by a three-step pulse with a suitable time delay, beam power, and total input energy less than what we have used in the volume ignition correspondence. The optimal beam pulse duration and power of each stage were calculated, and the target energy gain of 72 is obtained. In addition, the required driver energy reduced by 0.74 MJ. Furthermore, the volume ignition condition with a low fuel temperature of 1.8 keV and a low implosion velocity of 1.4 × 107 cm/s was established. A twofold pressure rise due to appropriate pulse shaping was also obtained. Finally, by investigating the e-folding parameter on the fuel-pusher interface, it is found that by applying a three-step pulse, the Rayleigh-Taylor instability factor (<5) is not too dangerous in the deceleration phase. Therefore, it may be concluded that the fusion system dynamic is now more stable.