Energy and particle confinement in MAST

Quasi-stationary H-mode plasmas have been produced on MAST and submitted to the ITPA H-mode confinement database. The MAST data are expanding the database by a factor of 2.2 in inverse aspect ratio ε=a/R and by a factor of 2.5 in toroidal β. The MAST energy confinement times broadly agree with the IPB98(y,2) scaling law. Merging with the published international database shows that the energy confinement time in MAST supports an ε dependence consistent with the subset of conventional shaped cross-section tokamaks when represented in engineering parameters. In dimensionless parameters, MAST indicates a collisionality dependence stronger than in the IPB98(y,2) scaling. MAST data strongly link ε and β scalings and as a result the proposed β independence would imply weak ε dependence. L-mode confinement exceeds the value given by the current L-mode scaling suggesting a stronger e dependence than predicted. In H-mode, the particle transport in the core is dominated by the Ware pinch and the neutral beam source. (author)