Carbon transport in the stochastic magnetic boundary of TEXTOR

For given conditions, significant change in main particle and carbon transport is observed in TEXTOR under the action of the Dynamic Ergodic Divertor, DED, operating both in 6/2 and 3/1 basic modes. In particular, the stochastic layer created at the plasma edge by the applied perturbing field, is responsible for the so called pump out, PO, effect (observed in DIII-D and on JET during experiments of ELM mitigation) characterized by a decrease in the plasma density and the reduction in the intrinsic carbon concentration in the plasma core. For a sufficiently high value of the applied field strength, in DED 3/1 basic operational mode a 3/1 island connects to the wall, with related further enhancement of particle transport. With respect to carbon, this phenomenon simply leads to a further carbon de-contamination from the central plasma. (C) 2009 Elsevier B.V. All rights reserved.