Demonstrating the ITER Baseline Operation at q95 = 3
In ITER, H-mode operation at 15MA and q95 = 3 is planned to achieve Q = 10 in deuterium-tritium mixtures. The Integrated Operation Scenario Topical Group of the ITPA has coordinated experiments in ASDEX Upgrade (AUG), Alcator C-Mod (C-Mod), DIII-D and JET to obtain H-mode data at q95 ~ 3. New databases have been generated for AUG and JET, using only data with the carbon wall at JET. The data span a wide range of operating conditions at q95 ~ 3, from discharges close to the H-mode threshold power (PLH) to H-modes at high input power (Pin/PLH = 4-5). H-modes close to PLH can achieve H98 ~ 1 and fGW > 0.8. However, at JET this is obtained at low ELM frequency, with fELM < 10Hz for Pin/PLH <1.1. At higher Pin/PLH = 2, the bulk of the data achieve H98 ~ 1, with the maximum achievable H98 factor increasing to 1.2. RF power has been used in ELMing Hmodes providing up to 60% of the total input power in AUG and up to 20% in JET, giving similar results compared to NB only discharges. In AUG, the use of RF has beneficial effects for achieving stationary discharges with the full W wall. Only C-Mod has 100% ICRF heated H-mode data at ITER relevant parameters and q95 ~ 3. A range of densities has been explored. High normalised density, fGW > 0.8, can be obtained at low input power in AUG and JET. At higher input powers and increasing Pin/PLH 2 however, the maximum achievable fGW decreases to 0.85. The experiments typically report a drop in the plasma inductance up to li(3)~0.7 with increasing plasma beta up to bN ~ 2.5. The maximum achievable H98 increases with beta. At high bN > 2.5, discharges at q95 ~ 3 in DIII-D and AUG reach H98 = 1.4 1.5, similar to hybrid regimes at q95 ~ 4. A remarkable similarity is observed in the data from the various devices for baseline H-modes at q95 ~ 3, giving confidence in projecting results to ITER.