Persistence of Spin-Polarization in Presence of High-Frequency Plasma Waves

Using a range of new computational tools, we calculate the depolarization rate of spin-polarized deuterium and tritium nuclei due to cyclotron-frequency plasma waves in realistic tokamak conditions. Contrary to previous estimates, we find that depolarization due to alpha particle-driven Alfvenic modes is weak. Under certain conditions, other Alfvenic modes can depolarize fuel, but we deem these conditions to be unlikely to lead to significant depolarization on transport timescales. These results indicate that if deployed, spin-polarized fuel could remain polarized sufficiently long to significantly increase the fusion reactivity in magnetic confinement fusion power plants.