Dynamic Self-Ignition of a Fusion Plasma

Abstract

A new criterion for fusion plasma ignition in d-t tokamaks is established by incorporating nonstationary reaction-thermal dynamics of the plasma into the analysis. Herein the application of a 'soft' Troyon beta limit, together with the actual fusion power deposition and its effect of deteriorating the plasma energy confinement time, are crucial parts of the hion burn dynamics which determine the ignition conditions. We find that the separatrix established by the dynamic trajectorial evolution of the plasma in the temperature-fuel ion density state plane -- not simply the zero power contour used previously -- is the critical boundary that must be exceeded for the stable ignited operating point to be attained, and maintained, without auxiliary heating.