High-gain inertial confinement fusion by volume ignition, avoiding the complexities of fusion detonation fronts of spark ignition

Summary form only given, as follows. The main approach to inertial confinement fusion (ICF) uses a high-temperature, low-density core and a high-density, low-temperature outer region of the laser(or ion beam-) compressed deuterium-tritium (D-T) fuel, in order to ignite a fusion detonation wave at the interface. This is an extremely delicate, unstable configuration which is very difficult to achieve, even with a carefully programmed time dependence of the deposition of the driver energy. This approach was devised in order to reach the high gains needed for low-efficiency lasers. Since 1978, several teams have developed an alternative scheme using volume ignition, where a natural and simple adiabatic compression, starting from a low initial temperature of 3 keV or less, is used. The high gains are obtained by self-heating due to the fusion reaction products plus self-absorption of Bremsstrahlung. Fortunately, a strong deviation from LTE occurs at ion temperatures above 100 keV, with much lower electron and even lower radiation temperatures. We report here how the gains calculated by different groups are relatively large, and despite detailed differences in the stopping power models, do not differ greatly.