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 thermal toroidal β. The MAST energy confinement times broadly agree with the IPB98(y, 2) scaling law. Merger 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 that the collisionality dependence might be stronger than in the IPB98(y, 2) scaling. MAST data link ε and β scalings and, as a result, the proposed β independence would imply smaller ε exponent. L-mode confinement exceeds the value given by the current L-mode scaling, suggesting a stronger ε dependence than predicted. In H-mode, the working particle transport in the core is dominated by the Ware pinch and the neutral beam source.