This paper describes the updates to and analysis of the International Tokamak Physics Activity (ITPA) Global H-Mode Confinement Database version 3 (DB3) over the period 1994-2004. Data have now been collected from 18 machines of different sizes and shapes: ASDEX, ASDEX

The condition of the latest version of the ELMy H-mode database has been re-examined. It is shown that there is bias in the ordinary least squares regression for some of the variables. To address these shortcomings three different techniques are employed: (a) principal component regression, (b) an error in variables technique and (c) the selection of a better conditioned dataset with fewer variables. Scalings in terms of the dimensionless physics variables, as well as the standard set of engineering variables, are also derived. The new scalings give a very similar performance for existing scalings for ITER at the standard βn of 1.6, but a much improved performance at higher βn.

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The most promising concept for deep fuelling a reactor is by the injection of compact toroid (CT) plasmoids. The first results showing CT fuelling of a tokamak plasma, without any adverse perturbation t o the tokamak discharge, are reported. The Compact Toroid Fueller (CTF) device was used to inject a CT-spheromak plasmoid into the TdeV tokamak. Following the CT penetration, the tokamak particle inventory increased by 16%, the loop voltage and the plasma current did not change, and there was no increase in magnetohydrodynamic (MHD) activity. The number of injected impurities was low and dominated by non-metallic elements. The plasma diamagnetic energy and the energy confinement time increased by more than 35%.

Abstract. The addition of high power, low aspect ratio data from the NSTX and MAST experiments have motivated a new investigation of the effect of aspect ratio on confinement scaling. Various statistical methods, including those that incorporate estimates of measurement error, have been applied to datasets constrained by the standard set of criteria in addition to the range of κ and M eff appropriate to ITER operation. Development of scalings using engineering parameters as predictor variables results in ε-scaling coefficients that range from 0.38 to 1.29; the transformation of these scalings to physics variables results in an unfavorable dependence of Bτ on β, but a favorable dependence on ε. Because the low aspect ratio devices operate at low B T and therefore high β T , a strong correlation exists between ε and β, and this makes scalings based on physics variables imprecise.