M Valovic | Searcharxiv

arXiv2014

Pellet fuelling with edge-localised modes controlled by external magnetic perturbations in MAST

The fuelling of plasmas by shallow frozen pellets with simultaneous mitigation of edge localised modes (ELM) by external magnetic perturbation is demonstrated on the MAST tokamak. Post-pellet particle loss is dominated by ELMs and inter-ELM gas fuelling. It is shown that the size of post-pellet ELMs can be controlled by external magnetic perturbations. Post-pellet ELMs remove particles from the large part of pellet deposition zone including the area with positive density gradient. The mechanism explaining this peculiarity of particle loss is suggested.

physics.plasm-ph↗

arXiv2013

Pellet fuelling of plasmas with ELM mitigation by resonant magnetic perturbations in MAST

Shallow fuelling pellets are injected from the high field side into plasmas in which ELMs have been mitigated using external magnetic perturbation coils. The data are compared with ideal assumptions in the ITER fuelling model, namely that mitigated ELMs are not affected by fuelling pellets. Firstly it is shown that during the pellet evaporation an ELM is triggered, during which the amount particle loss could be larger (factor ~1.5) than the particle loss during an ELM which was not induced by pellet. Secondly, a favourable example is shown in which post-pellet particle losses due to mitigated ELMs are similar to the non-pellet case, however unfavourable counter-examples also exist.

physics.plasm-ph↗