Particle balance analysis of RMP discharges in L- and H-mode at MAST*

The application of resonant magnetic perturbations (RMPs) at MAST has been shown to cause a reduction in density, the so-called particle pump-out effect, during discharges which have a particular MHD response. This can occur in both L-mode and H-mode discharges. An analysis of the changes in fueling and exhaust using a 0-D single reservoir particle balance of the main ion species has shown that during RMP application there is an increase in total fueling to the plasma but also a significant drop in particle confinement time such that there is a net particle pump-out. To more accurately calculate the recycling and particle fueling, a detailed analysis of the measured D_α emission was performed. Synthetic diagnostics were created with the ray-tracing code CHERAB using plasma sources from modelling of these discharges done with the 3-D plasma and neutral code EMC3-EIRENE. The generated synthetic images were compared to the corresponding absolutely calibrated images from experiment to better constrain the experimental measurements and account for surface reflections. Results show there is a relatively greater increase in fueling flux during RMP application than shown in the initial analysis, causing a greater reduction in the particle confinement time in that period.