Bremsstrahlung Emissions for Non-Thermal Distributions in Fusion Plasmas

In order to improve the reactivity of a confined fusion plasma, one may consider non-thermal components of the plasma distribution, where plasma streams collide at high relative speed to trigger fusion reactions. Ideally, the colliding plasmas would have the relative energy that is required for the maximum fusion energy yield: in the beam-like limit, this will be the relative energy corresponding to the peak of the fusion cross section. In these conditions, the thermal component of these plasma distributions, for both electron and ions, may not need to be large, as most of the energy is in the drift component. The realization of this scenario may make aneutronic fusion reactor concepts more appealing, since the confinement of large temperature plasma would no longer be needed. Along these lines, this work investigates the bremsstrahlung radiation losses for non-thermal, colliding plasmas, in order to estimate to what extent a low-temperature/large drift distribution can be beneficial. This, for a notional non-thermal plasma configuration, allows to establish, how closely the ideal fusion reactivity conditions may be realized. Examples for (quasi) aneutronic fusion fuels, considering both D-³He and p-¹¹B, are illustrated.