PROJECTIONS OF GYRORADIUS SCALING EXPERIMENTS TO AN IGNITION TOKAMAK

The confinement properties of future magnetic fusion devices can be ex trapolated from existing experiments using the scaling of heat transpo rt with relative gyroradius (p). For H mode confinement regimes, this extrapolation to smaller p is complicated by the requirement that th e loss power from core transport remain above the H mode threshold pow er. If the increase in H mode threshold power is more rapid than the i ncrease in loss power when p, becomes smaller, then the H mode thresh old determines the scaling of global confinement for large devices rat her than core transport. This can be avoided by choosing a scaling pat h at higher beta along which the loss power remains above the H mode t hreshold power to the point of ignition. The parameters for an ignitio n tokamak plasma that take full advantage of the gyro-Bohm-like scalin g of heat transport in H mode plasmas are presented.