Divertor heat loads in RMP ELM controlled H-mode plasmas on DIII-D

On DIII-D successful edge localized modes (ELMs) suppression with resonant magnetic perturbation (RMP) is always accompanied by splitting of the separatrix observable in the particle flux and under some conditions in the divertor heat flux patterns. In this work, we study the effects of n = 3 magnetic perturbation on the heat flux deposition patterns (including ELMs) at different levels of electron pedestal collisionalities (ν* < 0.2 and ν* ∼ 1) and triangularity. High collisionality results are compared to TEXTOR findings with Dynamic Ergodic Divertor at similar collisionalities (ν* ∼ 0.9). It has been found that the heat transport shows different reactions to the applied RMP depending on the plasma triangularity and collisionality of the plasma boundary. In the ITER-like discharges ELMs produce several helical striations on the target with width of the deposition pattern increasing linearly with the ELM size. Application of the RMP causes remaining ELMs (before they are completely suppressed) to lock to the externally induced magnetic structure, which holds true also for ELM-like bursts caused by D2 pellets. (author)