Targeting a Versatile Actuator for EU-DEMO: Novel Control Scheme for Multisource Pellet Injector

Reactor plasma core fueling requires the injection of cryogenic pellets, most probably composed of a mixture of D₂ and T₂. Likely, pellet injection will be the most important actuator for plasma core density control. Therefore, pellet injection systems must be developed further that are capable of acting as actuator for density control. A novel control scheme is developed based on a centrifuge acceleration system. This scheme considers every available pellet launching slot and compares the current particle flux with the requested one. The response time is within the granularity of the available launching slots, in this case between 7 and 12 ms. First plasma experiments in feedforward mode showed excellent results, providing a good basis for upcoming plasma core density feedback control development activities.