  Non-Maxwellian distributions of particles are commonly observed in fusion
studies, especially for magnetic confinement fusion plasmas. The particle
distribution has a direct effect on fusion reactivity, which is the focus of
this study. We investigate the effects of three types of non-Maxwellian
distributions, namely drift-ring-beam, slowing-down, and kappa super-thermal
distributions, on the fusion reactivities of D-T (Deuterium-Trillium) and p-B11
(proton-Boron) using a newly developed program, where the enhancement of fusion
reactivity relative to the Maxwellian distribution is computed while keeping
the total kinetic energy constant. The calculation results show that for the
temperature ranges of interest to us, namely 5-50 keV for D-T and 100-500 keV
for p-B11, these non-Maxwellian distributions can enhance the fusion
reactivities. In the case of the drift-ring-beam distribution, the enhancement
factors for both reactions are affected by the perpendicular ring beam
velocity, leading to decreased enhancement in low temperature range and
increased enhancement in high temperature range. However, this effect is
favorable for p-B11 fusion reaction and unfavorable for D-T fusion reaction. In
the slowing-down distribution, the birth speed plays a crucial role in both
reactions, and increasing birth speed leads to a shift in the enhancement
ranges towards lower temperatures, which is beneficial for both reactions.
Finally, the kappa super-thermal distribution results in a relatively large
enhancement in the low temperature range with a small high energy power-law
index {\kappa}. Overall, this study provides insight into the effects of
non-Maxwellian distributions on fusion reactivity and highlights potential
opportunities for enhancing fusion efficiency.
