STORM modelling of scrape-off layer filament behaviour with hot ions

Abstract Advances in edge and scrape-off layer diagnostics have shown that often the ion temperature is higher than the electron temperature in scrape-off layer filaments. We have therefore extended the STORM model beyond the cold ion limit commonly used, to allow for the inclusion of hot ion effects in the slab geometry used to investigate filament dynamics. We find that filaments are both faster and more coherent than in a cold ion model, resulting in increased particle transport. We trace the differences back to the effect of individual hot ion terms, compared using an isothermal ion model. Evolving ion temperature has a modest additional effect on net particle transport, but an ion temperature perturbation in a filament can counteract the instability caused by an electron temperature perturbation.