Helium Oscillations in Burning Tokamaks

Abstract

Thermonuclear alpha particles transfer their energy by slowing down on the electrons and ions of bulk plasma, after which time the alpha particles become helium ash, which dilutes the plasma and reduces the fusion rate. The helium ash is shown to cause temperature oscillations that are unacceptable for reactor performance, but as an example, an ITER-like plasma is used to demonstrate that these oscillations can be controlled effectively by modulating auxiliary power.