Optimized ion temperature heating in tokamak reactor plasma

The problem of optimizing ion heating efficiency is put in the perspective of minimizing the risk of missing ignition in a future thermonuclear machine. Starting from a 0-D system dynamics representation adapted for properly including control variables, it is shown, when taking account of the main physical effects affecting the behavior of this system, that there exists a balanced splitting of power input into neutral beam injection and RF (ion cyclotron harmonics) injection so that the α-power release is largest for fixed total power input. When combined with technological and physical constraints, this defines interesting parameters so that system performances are made the most insensitive to uncertainties