Ignitor physics assessment and confinement projections

An independent assessment of the physics of Ignitor is presented. Ignitor is a physics demonstration experiment with the main goal of achieving thermonuclear ignition, defined as the regime where fusion alpha heating compensates for all forms of energy losses. Simulations show that a pulse of alpha particle power of up to 10-20 MW is produced for a period of more than a few seconds. Crucial issues are the production of peaked density profiles on a timescale of several energy confinement times, the control of current penetration for the optimization of ohmic heating and sawtooth avoidance. The presence of a 10-20 MW ICRF system and the operation of a high speed pellet injector are considered essential to provide added flexibility in order to counter unexpected, adverse plasma behaviour.