Scrape-off layer ion temperature measurements at the divertor target in MAST by retarding field energy analyser

Knowledge of the ion temperature (Ti) is of key importance for determining heat fluxes to the divertor and plasma facing components, however data regarding this is limited compared to electron temperature (Te) data. Ti measurements at the divertor target, between edge-localised modes (inter-ELM) H-mode, have been made using a novel retarding field energy analyser (RFEA). Unlike previous L-mode measurements where Ti=Te, results from a range of H-mode discharges have shown that at the target Ti/Te=1.5–3. The heat flux profiles calculated using these Ti measurements combined with data from the Langmuir probes give a comparison to that measured by infra-red camera.