Pellet injection algorithm for the FFHR helical reactor

Abstract

Pellet injection algorithm has been proposed for engineering developments in the force free helical reactor (FFHR) based on the zero-dimensional equations. In general, the plasma parameters, such as the density, the temperature and hence the fusion power, may oscillate by repetitive pellet injections during the ignition access and steady state phase. Pellet injection with a higher frequency cannot solely remove oscillation of the fusion power because it is injected irregularly. Gas puffing with the slow time response using the same signal of the fusion power can compensate these oscillations to some level because pellets are injected cyclically. When two pellet systems work alternatively out of phase together with the slow gas puffing, the fusion power oscillation is smallest. In addition, even when the fuel particle confinement time becomes long due to wall saturation, the fusion power and density can be controlled during the fusion burn phase as long as the helium ash can be removed.