Inherent Characteristics of Fusion Power Systems: Physics, Engineering, and Economics

Performance scaling of fusion power sources shows that Maxwellian, magnetic, local-thermodynamic-equilibrium (MM/LTE) devices require much larger sizes and B fields than do electron-driven, inertial-electrostatic-confinement (EXL/IEC) systems for the same output. Basic economics analyses show that systems of either type must be small in size to be economically viable. This requires operation at high fusion power density and first-wall thermal fluxes; flux levels needed are well within those of practical power engineering experience. The EXL/IEC systems can satisfy these demands more readily than can MM/LTE systems. They can be operated to avoid particle thermalization, preserve ion core convergence, and yield a large power gain against losses (e.g., bremsstrahlung) for all fuels from deuterium-tritium to p-¹¹B and ³He³He. Direct conversion of charged-particle energy, without arcing, is inherently straightforward in the quasispherical field geometry. If losses prove to be governed by classical physics phenomena rather than turbulent transport, all research and development (R&D) from physics studies to power plants can be done at a single size (≈3-m radius) and B field (≈1.2 T, 12 kG); no scaling growth in size or field is required. Consequent R&D costs and time scales are estimated to be <12 years and $1 billion for development of prototype EXL/IEC fusion power systems. Research investment seems warranted in this small-scale alternative to large-scale MM/LTE systems.