Spherical tokamak as model for next steps in fusion energy

Among the top puzzles in the development of fusion energy is the best shape for the magnetic facility--or "bottle"--that will provide the next steps in the development of fusion reactors. Leading candidates include spherical tokamaks, compact machines that are shaped like cored apples, compared with the doughnut-like shape of conventional tokamaks. The spherical design produces high-pressure plasmas--essential ingredients for fusion reactions--with relatively low and cost-effective magnetic fiel...