Fusion energy in degenerate plasmas

Abstract

In inertial confinement fusion (ICF), a high density, low temperature plasma can be obtained during the compression phase, so minimizing the energy needed for compression. If the final temperature reached is low enough, the electrons of the plasma can be degenerate. In this case, bremsstrahlung emission is strongly suppressed and ignition temperature becomes lower than in classical plasmas, which offers a new design window for ICF. Fusion ignition can then be triggered by an additional energy beam. The main difficulties to produce degenerate plasmas are the compression energy and the compression performance needed for it. Besides that, the low specific heat of degenerate electrons (as compared to classical values) is also a problem because of the rapid heating of the plasma. The main contribution of the Letter is to show that the plasma degeneracy lowers the ignition temperature for DT plasmas, but it does not increase the target energy gain. Some numerical results are given on that. In the case of proton–boron 11 plasmas, the densities have to be extremely high in order to reduce the ignition temperature, but even so the energy gains remain rather low.