Dinklage, AndreasMaassberg, HenningPreuss, RolandYamada, HiroshiAscasibar, EBeidler, CFunaba, HisamichiHarris, JeffreyKus, AMurakami, SSano, FStroth, USuzuki, Y2015-12-100029-5515http://hdl.handle.net/1885/60081The International Stellarator Confinement Database (ISCDB) is a joint effort of the helical device community. It is publicly available at http://www.ipp.mpg.de/ISS and http://iscdb.nifs.ac.jp. The validity of physics models is investigated employing ISCDB data. Bayesian model comparison shows differences in the confinement scaling of data subgroups. Theory-based assessment of pure neoclassical transport regimes, however, indicates scalability which is supported by experimental results in specific W7-AS scenarios. Therefore, neoclassical simulations are employed for predictive purposes in W7-X, accounting for effects due to power deposition, plasma profiles and the ambipolar radial electric field. Neoclassical case studies for W7-X are presented as examples for the neoclassical predictions to be considered as an upper limit of plasma performance.Keywords: Ambipolar radial electric fields; Bayesian model; Energy confinement; Helical devices; Neoclassical transport; Physical model; Plasma performance; Plasma profiles; Power deposition; Time-scaling; Upper limits; Bayesian networks; Electric fields; Magnetohy200710.1088/0029-5515/47/9/0252015-12-10