Density Pump-Out Compensation during Type-I ELM Control Experiments with n = 1 Perturbation Fields on JET
Experiments to balance the density pump out effect during ELM control through the application of an n = 1 magnetic perturbation in Type-I Hmode plasmas at JET are presented, describing the effect on Te, ne and pe profiles. Reference discharges during H-mode with and without RMP are first considered, and compared to results obtained in previous work. Pellet and gas injection are the two applied techniques; on the basis of previous experience, various particle fuelling rates have been tested on two different divertor configurations, finding those for which the compensation takes place. In terms of plasma confinement, while core pressure is found to be almost unvaried with the particle fuelling, the edge pressure pedestal improves towards the value obtained during the H-mode without the application of the magnetic perturbation. The edge stability analysis shows that the mitigated edge plasma even with the addition of particle fuelling is in the stable region against the Type-I ELM triggering peeling-ballooning modes.