Particle, heat, and sheath power transmission factor profiles during ELM suppression experiments on DIII-D

Edge localized modes (ELMs) are predicted to be a significant problem for ITER due to impulse heating of the divertor target plates. During low collisionality experiments on DIII-D where ELMs were suppressed using resonant magnetic perturbations (RMP), target plate profiles of particle flux electron temperature (T-e), and floating potential (V-f) have been measured with Langmuir probes (LP) and compared to IRTV heat flux profiles. During ELM suppression, J(sat) and T-e increase and the J(sat) profile broadens. A three-peak structure, most visible in the V-f, agrees with the spacing and q(95) dependence of an n = 3 toroidal pattern predicted by the TRIP3D code. The heat flux calculated from Langmuir probe data (using sheath theory) is observed to get similar to 2x larger during ELM suppression than between ELMs before the RMP is turned on. The sheath power transmission factor profile has been determined from IRTV and Langmuir probe data. (C) 2009 Elsevier B.V. All rights reserved.