The multistage depressed collector (MDC) shall be one of the key technologies to achieve the
required gyrotron efficiency in the DEMOnstration fusion power plant. For the first time this
work presents a comprehensive study of possible gyrotron MDC concepts. Concepts only using
axisymmetric E- and B-field components are shown to be insufficient. Instead promising
concepts using the E×B drift are proposed. A detailed study of a novel MDC concept using an
azimuthal electric field is presented.
