Plasma Confinement Requirements for Compact RFP Reactor (Titan) Plasmas Operated in a High-Radiation Mode^†

Essential to the achievement of economically compact fusion power cores is the radiation of a large fraction of the plasma heating power uniformly to the first wall, thereby assuring adequate longevity of the divertor impurity control system. The radiation of significant fractions of the heating power from the beta-limited core-plasma region in an RFP, however, requires a corresponding increase in the quality of (non-radiative) confinement. It is shown that radiating ≳ 70% of the total heating power from the core plasma of the TITAN compact reversed-field-pinch (RFP) reactor is possible with non-radiative confinement times that are a large factor (> 15) below classical confinement predictions and are within the present scaling relation based upon extrapolations of the existing RFP transport database. By comparison, the confinement in the ARIES-I tokamak reactor is within a factor of 2 of neo-classical predictions.