Diffusive Losses and Scaling Law for Large Tokamaks

Under plasma conditions aimed for in the next generation of tokamak devices, it is necessary to consider a multi-parameter model for diffusive energy losses which would limit the temperatures and confinement times attainable. In this paper, we study a model for plasma diffusion in a reactor size tokamak considering various plasma parameters (like density, temperature, spatial gradients, collisional effects, etc.) and also topological elements of the magnetic configuration (like magnetic shear, magnetic curvature, etc.).