(EX/P4-1) Hydrocarbon Characteristics in Fusion Edge Plasmas from Electron-Molecule and Ion-Surface Collision Experiments

A. Kendl1), K. Becker2), S. Denifl1), O. Echt3), N. Endstrasser1), B. Farizon4), M. Farizon4), S. Feil1), L. Feketeova1), V. Grill1), Z. Herman5), T. D. Märk1)6), S. Matejcik6), S. Matt-Leubner1), M. Probst1), B. Rasul1), P. Scheier1), W. Schustereder7), J.D. Skalny6), P. Sulzer1), M. Winkler1), F. Zappa1)
1) Institute for Ion Physics and Applied Physics, Association Euratom-ÖAW, University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
2) Polytechnic Institute of New York University, Brooklyn, NY, USA
3) Department of Physics, University of New Hampshire, Durham, NH, USA
4) Université de Lyon, F-69003, Lyon,France; Université Lyon 1,Villeurbanne; CNRS/IN2P3, UMR5822, IPNL France
5) J. Heyrovsky Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
6) Department of Experimental Physics, Comenius University, Bratislava, Slovakia
7) Max-Planck-Institut für Plasmaphysik, Euratom-Association, Garching, Germany

Abstract.   The compatibility of reactor grade plasmas with plasma facing materials at the first wall is one of the present challenges in fusion research. In order to understand and elucidate the role of radiative and collisional processes in the edge plasma region, it is essential to have available detailed and quantitative knowledge on the corresponding elementary reactions proceeding in the volume before and at the wall. Surface processes involving hydrocarbons and their ions, which are probable vacuum contaminants in plasma devices, and the role of hydrocarbon chemistry and transport in divertor plasmas are some of the key components in modelling predictions for ITER based on atomic and molecular data. Improved data sets for hydrocarbons and detailed and accurate knowledge of the cross sections of the relevant plasma chemical volume and wall processes are needed. In this context we have carried out: electron (proton and helium) impact excitation/ionization reactions with possible plasma edge atoms, molecules and ions; determination of relevant differential, partial and total cross-sections and reaction rate coefficients for electron-molecule and ion-surface collisions; investigation of the temperature dependence of ionization energies and ionization cross sections and electron attachment cross sections; and calculations of inelastic interactions between electrons and atoms, molecules and molecular ions. The reported work supports the provision of essential data commonly needed for diagnostics and modelling across the fusion programme.

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