1. aCRPP, EURATOM–Confédération Suisse, EPFL, CH-1015 Lausanne, Switzerland
2. bEFDA Close Support Unit, Boltzmannstrasse 2, D-85748 Garching, Germany
3. cSchool of Electrical and Computer Engineering, National Technical University of Athens Association EURATOM-Hellenic Republic, 9 Iroon Polytechniou st. GR-15772 Athens, Greece
4. dThales Electron Devices (TED), 2 Rue de Latécoère, F-78141 Vélizy-Villacoublay, France
5. eIstituto di Fisica del Plasma, Association EURATOM–ENEA-CNR, 20125 Milano, Italy
6. fInstitute of Solid State Physics, University of Latvia, Kengaragastr. 8, LV-1063, Riga Latvia and Helsinki University of Technology, Association EURATOM-TEKES, FIN-02150 Espoo, Finland
7. gForschungszentrum Karlsruhe, IHM, EURATOM-FZK, D-76021 Karlsruhe, Germany
8. hForschungszentrum Karlsruhe, IHM, EURATOM-FZK, D-76021 Karlsruhe, Germany and Universitaet Karlsruhe Institut fuer Hoechstfrequenztechnik und Elektronik, D-76131 Karlsruhe, Germany