Tokamaks Approaching Ignition Conditions

Abstract

An analysis (in terms of different figures of merit) of the performances of several recently proposed tokamaks (IGNITOR, Compact Ignition Tokamak, IGNITEX, JIT, Enhanced Tokamak, Next European Torus, Candor) has been performed. The analysis was carried out according to different scaling laws and in various operating scenarios (temperature and density profile control, low and high energy confinement modes). In the plasma model, profile consistency between current density and temperature was assumed, taking into account neoclassical conductivity and the related physical constraints. The profiles obtained simulate the experimental data fairly well for both lower and higher collisional plasmas. A code was developed for this purpose that produces the stationary state contours for a given tokamak at different additional power levels once the scaling law is fixed. For a given machine, automatic analyses of these diagrams can be carried out for different confinement scaling laws and operating conditions. For a given scaling law and operating scenario, the code scans the configuration space looking for the “machines” capable of reaching ignition according to some simple technological constraints. The results for the most conservative situation are also shown.