Kiel 2004 – wissenschaftliches Programm

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P: Plasmaphysik

P 8: Plasma-Wand-Wechselwirkung I

P 8.2: Fachvortrag

Dienstag, 9. März 2004, 15:45–16:05, H\"orsaal D

First results of the impact of the Dynamic Ergodic Divertor DED on transport in the plasma edge of TEXTOR measured by thermal atomic beam diagnostics — •Oliver Schmitz, Marcin Jakubowski, Michael Lehnen, Ulrich Samm, Bernd Schweer, and Bernhard Unterberg — Institut für Plasmaphysik, FZ Jülich, Trilateral Euregio Cluster, EURATOM-Assoziation, 52425 Jülich, Germany

The Dynamic Ergodic Divertor (DED) has recently been installed in the TEXTOR Tokamak. It consists of 16 magnetic coils wound helically around inside the torus at the High Field Side (HFS). A magnetic field pertubation resonant with different m and n mode numbers is induced to the plasma edge of TEXTOR. An ergodic zone (long connection lengths of the magnetic field to the wall) and a laminar zone (short connection lengths) are formed. In this laminar zone the DED forms a helical divertor. To investigate the impact of these pertubations on transport we use beam emission spectroscopy of thermal atomic beams. The electron density n_e is measured by a thermal Lithium beam at the Low Field Side (LFS). With the Helium beam diagnostics installed both at the LFS and at the HFS of TEXTOR one can measure n_e and the electron temperature T_e simultaneously.
In this contribution first indications of the effects of the DED on edge transport, e.g. changes in the n_e decay length, are presented. These findings are related to the observations of the DED structures at the inner wall with a H_α sensitive camera and to the topology of the magnetic field.