Effects of resonant magnetic perturbations on divertor target power loads in COMPASS-D

摘要

The effect of externally applied resonant magnetic perturbations on the power load to the divertor target is studied in the COMPASS-D tokamak. A theoretical model is constructed, based on detailed field-line tracing, allowing for cross-field transport in the scrape-off layer (SOL). In this model, the perturbations give rise to an `ergodic' layer that modifies the transport properties in the SOL, causing a net radial spread in the power loading. Spiral magnetic structures form on the divertor target, giving rise to `hotspots' near their toroidal turning points and a double peak structure to the inboard and outboard divertor strike zones. For the first time, detailed comparisons are made between model and experiment, obtaining good agreement when the amplification of the applied field, due to the requirements of pressure balance in the plasma, is included.