Lawson concepts and criticality in DT fusion reactors

Abstract

The original Lawson concepts (amplification factorR and parameternτ as well as their applications in DT reactors are discussed in two cases: the ignition regime and the subignition regime in a self-sufficient plant. The modified Lawson factor or internal amplification factorR _α (a function of alpha power) is proposed as a means to measure the ignition level reached by the plasma, in a more precise way than that given by the collective parameter (nτkT). The self-sufficiency factor (δ) is proposed as a means to measure the plant self-sufficiency,δ being more significant than the traditionalQ factor. It is stated that the ignition regime (R _α =1) is equivalent to a critical state (energy equilibrium); then, the corresponding critical mass concept is proposed. The analysis of theR _α relationship with temperature (kT), (nτ), and recirculating factor (ɛ) gives the conditions for the reactor to reach ignition or for the plant to reach self-sufficiency; it also shows that an approach to ignition is not improved by heating from 50 to 100 KeV.