Proton-boron fusion scheme taking into account the effects of target degeneracy

The proton -boron (p -11B) reaction is regarded as the holy grail of advanced fusion fuels, since the primary reaction produces three alpha particles with few neutrons and induced radioactivities from second order reactions. Compared to the deuterium -tritium reaction a much higher reaction temperature is required. Moreover, bremsstrahlung energy losses due to the high nuclear charge of boron deem it seemingly apparent than a fusion reactor based on deuterium -tritium plasma in equilibrium is to say the least very difficult. It is becoming more appealing to collide intense laser beams or accelerated proton beams with a boron target to produce p -11B reactions. The fusion yield of p -11B reactions is closely related to proton beam parameters and boron target conditions such as density, temperature, and ingredients. Degeneracy will increase fusion yields by reducing the stopping power of injected protons. In this work, we suggest a scheme for beam -target p -11B fusions via injecting a MeV proton beam into a highly compressed quantum degenerated boron target. Such a boron target can be achieved via quasi-isentropic compression of solid boron by using precisely shaped laser pulses. Our results indicate that for densities ranging from 103 to 104 rho s, where rho s is the density of solid boron, contributions of bound and free electrons to the stopping of protons can be completely disregarded and dramatically reduced, respectively. The result is an increase in fusion yield by orders of magnitude. Furthermore, in order to achieve multiplication factor F greater than one, with F defined as the ratio of output fusion energy to the energy of injected protons, it is found there exists a minimum possible density of boron target, which is 1.8 x 105 rho s when the kinetic energy of injected protons is 880 keV.