Since the installation of an ITER-like wall, the JET programme has focused on the consolidation of ITER design choices and the preparation for ITER operation, with a specific emphasis given to the bulk tungsten melt experiment, which has been crucial for the final decision on the material choice for the day-one tungsten divertor in ITER. Integrated scenarios have been progressed with the re-establishment of long-pulse, high-confinement H-modes by optimizing the magnetic configuration and the use of ICRH to avoid tungsten impurity accumulation. Stationary discharges with detached divertor conditions and small edge localized modes have been demonstrated by nitrogen seeding. The differences in confinement and pedestal behaviour before and after the ITER-like wall installation have been better characterized towards the development of high fusion yield scenarios in DT. Post-mortem analyses of the plasma-facing components have confirmed the previously reported low fuel retention obtained by gas balance and shown that the pattern of deposition within the divertor has changed significantly with respect to the JET carbon wall campaigns due to the absence of thermally activated chemical erosion of beryllium in contrast to carbon. Transport to remote areas is almost absent and two orders of magnitude less material is found in the divertor.

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A high-powered helium microwave-induced plasma was developed, and preliminary characterizations are presented. This kilowatt-plus microwave-induced plasma (KiP-MIP) was contained in a helical flow quartz torch. Power was transferred via waveguides from a 3.0-kW, 2.45-GHz, 120-pulses-per-second microwave generator to a waveguide-to-coaxial converter. A modified Beenakker TM010 resonator cavity was used to focus the energy. Effects of the magnitude of applied power on helium line emission intensities were studied, as well as comparisons of the temporal output of generator output and helium line emission. Introduction of gaseous halogens (Cl2, CBr4) produced intense ion emission which follows the intensity ratios commonly observed in He-MIPs.

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