On the thermodynamics of IGNITOR plasma

Independent assessment of the feasibility of controlled nuclear fusion in the proposed IGNITOR tokamak is difficult because of the uncertainties concerning energy transport in the plasma. We discuss one IGNITOR scenario with the help of well-known general constraint on transport in weakly collisional, axisymmetric, toroidal, low-β turbulent plasma. No particular ad hoc model for transport coefficients is invoked. As a result, the relevance of the Coppi-Mazzuccato-Gruber model is questioned. Moreover, the crucial role of temperature pedestal at the boundary is highlighted.