AbstractIn this paper, the array of Langmuir probes at the COMPASS‐D divertor and the analysis and interpretation of the probe data are described. The divertor probe system consists of 39 graphite single Langmuir probes embedded in the divertor target. The probe array is being used to investigate the properties of the divertor plasma on COMPASS‐D single‐null X‐point discharges; its high spatial and temporal resolutions allow a detailed study of a variety of fast phenomena such as fluctuations and ELMs. Results on these topics are also pr