Lawson concepts and criticality in DT fusion reactors

The original Lawson concepts and their applications in deuterium-tritium reactors are discussed with reference to two cases: the ignition regime and the subignition regime in a self-sufficient plant. The modified Lawson factor or internal amplification factor is proposed as a means to measure the ignition level reached by the plasma in a more precise way than that afforded by the collective parameter. The analysis of the internal amplification factor relationship with temperature and recirculating factor gives the conditions for the reactor to reach ignition or for the plant to reach self-sufficiency.