A novel approach to ICF ignition

Summary form only given. NIF´s ignition campaign has attracted a great attention recently due to its significance to the future of fusion researches worldwide. Recent experiment results have demonstrated both hopes as well as challenges faced by the NIF team. One of the greatest challenges is to achieve desired areal density ρR for both fuel and hot-spot regions so that a self-sustained TN burn could be initiated and maintained. Unfortunately, the recent results from the NIF´s ignition shots indicated that the desired equivalent areal density ρR has not been reached during the ignition time for a self-sustained thermonuclear burn. In this presentation, We will propose a novel approach to achieve a greater ρR in the fuel and especial hot-spot in additional to what the NIF can achieve by utilizing radiative cooling mechanism in the end of the implosion phase to give both the hot-spot and fuel an additional push so that a higher areal density ρR can be reached just before ignition. The proposal of radiative cooling is counter intuitive at the first sight. In the past, the radiative cooling caused by mixing of high Z material into the gas region was considered as a degradation factor to the performance of ICF capsule. However, in this presentation, we will demonstrate that with a proper implementation of radiative cooling during final implosion phase it will enhance the performance margin dramatically. The two immediate benefits of the radiation cooling are: (a) the cooling of the fuel in the final implosion phase reduces pressure of the fuel so that a better compression can be achieve; and (b) the radiation cooling reduces the ion temperature of the fuel and gas momentarily which in turn results in a delay of thermonuclear burn ignition such that additional few picoseconds are acquired to implode the capsule further. Moreover, another important feature of this approach is that all the previous researches and efforts of the NIF campaig- can be fully utilized, for example, laser pulse shaping, holhraum physics, laser-plasma interaction, even capsule design [Haan, S.W., et al., 2011; Landen, O.L., et al., 2011; Lindl, J., 1995], since the only difference this new approach is to add an additional doping in the gas region. Over 38% of improvement of gas (hot-spot) ρR and 50% increase of the yield rate compared to that of the NIF baseline point design (Rev. 5B) have been achieved using this approach with the identical drive conditions.