This is an analysis of the H-mode threshold physics by theInternational H-mode Threshold Database Working Group. The data from 10different tokamaks world-wide are combined in an attempt to determine thephysics of the H-mode transition as well as the scaling of the plasmaparameters relevant to the H-mode transition to future magnetic fusiondevices. The input power required to achieve H-mode is fitted with log-linearregressions of global plasma parameters such as density, toroidal magneticfield and plasma size. An attempt to cross-validate this analysis method ismade by removing each tokamak in turn and recalculating the fit. Based onthese global scalings, the hysteresis in the threshold power can be definedin terms of how far away from the threshold scaling plasma parameters can beobtained and remain in H-mode. Local edge temperatures and densities are alsoanalysed at the H-mode threshold in an attempt to find a scaling with plasmaparameters. Changes in divertor geometry also have strong effects on theH-mode threshold, so scalings are compared for open and closed divertors.
Scaling of power threshold for edge transport barrier formation in CHS with density, magnetic field and magnetic configuration