Enhancement of reactivity by RF in reactors

This lecture deals with the possibility to increase the reactivity in a reactor by creating a population of fast fuel ions. The problem of igniting a reactor using additional heating power in face of the confinement degradation is first briefly reviewed in terms of the global power balance of the reactor and the (nτ_ET) diagram. Then the different possible ways of heating fuel ions and creating a fast ion population in a reactor plasma are discussed. Finally, the effect of energetic tails on reactivity is investigated using the JETTO transport code. At the same time, these transport simulations allow to compare electron and ion heating methods in their effectiveness for enhancing the reactivity and controlling the plasma bum. These questions are illustrated using a very simple 0-D transport model. A more detailed analysis of the JETTO simulations can be found in Ref.1.