PLASMA TRANSPORT IN A COMPACT IGNITION TOKAMAK.

Nominal predicted plasma conditions in a Compact Ignition Tokamak (CIT) are illustrated by transport simulations using experimentally calibrated plasma transport models. The range of uncertainty in these predictions is explored by using various models that have given almost equally good fits to experimental data. Using a transport model that best fits the data, thermonuclear ignition occurs in a CIT design with a major radius of 1. 32 m, plasma half-width of 0. 43 m, elongation of 2. 0, and toroidal field and plasma current ramped in 6 s from 1. 7 to 10. 4 T and 0. 7 to 10 MA, respectively. Ignition is facilitated by 20 MW of heating deposited off the magnetic axis near the **3He minority cyclotron resonance layer. Under these conditions, sawtooth oscillations are small and have little impact on ignition. Tritium inventory is minimized by preconditioning most discharges with deuterium. Tritium is injected, in large frozen pellets, only after minority resonance preheating. Variations of the transport model, impurity influx, heating profile, and pellet ablation rates have a large effect on ignition and on the maximum beta that can be achieved.