EFFECTS OF RESONANT MAGNETIC PERTURBATIONS ON DIVERTOR TARGET POWER LOADS IN COMPASS-D

The effect of externally applied resonant magnetic perturbations on th e power load to the divertor target is studied in the COMPASS-D tokama k. A theoretical model is constructed, based on detailed field-line tr acing, allowing for cross-field transport in the scrape-off layer (SOL ). In this model, the perturbations give rise to an 'ergodic' layer th at modifies the transport properties in the SOL, causing a net radial spread in the power loading. Spiral magnetic structures form on the di vertor target, giving rise to 'hotspots' near their toroidal turning p oints and a double peak structure to the inboard and outboard divertor strike zones. For the first rime, detailed comparisons are made betwe en model and experiment, obtaining good agreement when the amplificati on oi the applied field, due to the requirements of pressure balance i n the plasma, is included.