An important part of the ITER Research Plan [1] is the Pre-Fusion Power Operation (PFPO) phase, which includes demonstration of H-mode plasma operation and the commissioning of ELM control systems. However, since hydrogen or helium are the main ion species in PFPO plasmas, the L–H power threshold P_L–H is expected to be considerably higher than equivalent D and D–T plasmas, which restricts operation in terms of toroidal field and plasma density.

Here, we study the possibility for stable ELMy H-mode operation in hydrogen or hydrogen dominant plasma at 7.5MA/2.65T. The scenario is modelled self-consistently using JINTRAC [2] for integrated core, edge and SOL/divertor modelling. Results have indicated that a stable ELMy H-mode is indeed accessible for 7.5MA/2.65T hydrogen plasma, although successful operation requires either a 10MW upgrade of the ECRH systems or inclusion of a helium minority for lowering of the L–H power threshold.

References
[1] ITER Technical Report ITR-18-03 (2018). https://www.iter.org/technical-reports
[2] Romanelli et al., Plasma Fusion Res. 9, 340323 (2014)