A compact fusion advanced closed-Rankine cycle (CFAR) based on the less expensive “in-situ” nonequilibrium MHD (magnetohydrodynamic) conversion with assistance from synchrotron radiation superheat in the “microwave” tokamak using synchrotron radiation both for MHD energy conversion and current drive is studied for the improvement of tokamak fusion reactor economy.In this CFAR concept, superheat of flowing slightly-ionized gases by synchrotron radiation energy plays a very important role in the system cycle efficiency, using solely MHD electrical power generation.This paper describes a two-dimensional microwave superheat model and examines the above envisaged concept, which is a key issue in the CFAR cycle.