Reactor assessments of advanced bumpy torus configurations

Recently, several configurational approaches and concept improvement schemes were introduced for enhancing the performance of the basic ELMO Bumpy Torus (EBT) concept and for improving its reactor potential. These configurations include planar racetrack and square geometries, Andreoletti coil systems, and bumpy torus-stellarator hybrids (which include twisted racetrack and helical axis stellarator - snakey torus). Preliminary evaluations of reactor implications of each of these configurations have been carried out based on magnetics (vacuum) calculations, transport and scaling relationships, and stability properties. Results indicate favorable reactor projections with a significant reduction in reactor physical size as compared to conventional EBT reactor designs carried out in the past. Specifically, with these advanced configurations, reactors with R approx. = 20 + or - 3 m are found to be possible; this is almost a factor of 2 reduction in size compared to recent EBT reactor design points with R approx. = 40 + or - 5 m (which utilizes symmetrizing coils for an aspect ratio enhancement) for comparable power outputs. (Here R is defined as 2πR-equivalent major radius.) This makes it possible for operating at high wall loadings (about 2-4 MW/m2 instead of about 1-1.5 MW/m2) and increased engineering fusion power density