Resonant features of energy and particle transport during application of resonant magnetic perturbation fields at TEXTOR and DIII-D

In this paper, results of a direct comparison of TEXTOR and DIII-D experiments with resonant magnetic perturbation (RMP) fields are presented. This comparison of resistive L-mode plasmas at TEXTOR with highly conductive H-mode plasmas at DIII-D is useful to identify generic physics mechanisms during application of RMP fields with a strong field line pitch angle alignment in the plasma edge. A reduction in the pedestal electron pressure p e with increasing extension of the vacuum modelled stochastic layer and p e recovery with decreasing layer width is found caused by a q 95 resonant reduction in the edge (0.8< N<0.95) electron temperature T e(q 95) on both devices. For RMP edge-localized mode (ELM) suppressed H-mode plasmas at DIII-D, the gradients T e and nominal values of T e are reduced in this edge region while increasing in the pedestal (0.95< N<1.0) with RMP field applied and both are highly dependent on q 95. In contrast, an increase in the central ion temperature with strong steepening of the ion temperature profile at mid-radius is foundagain being highly dependent on q 95. However, these resonant thermal transport effects are only seen in high triangularity plasmas revealing a strong shape dependence of the thermal transport. In contrast to the highly q 95 dependent thermal transport features, the reduction of n eknown as density pump outshows a much weaker dependence on q 95. We show the potential to reduce the RMP induced particle pump out by fine tuning of the RMP spectral properties. At low resonant field amplitudes enhanced particle confinement is seen in high-field side limited L-mode discharges on both devices while higher resonant field amplitudes yield particle pumps out. © 2012 IAEA, Vienna.

Published in:
Nuclear Fusion, 52, 4, 043005

 Record created 2013-03-18, last modified 2018-01-28

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