[1] CIEMAT Fus, EURATOM Assoc, Madrid 28040, Spain
[2] ENEA Fus, EURATOM Assoc, I-35127 Padua, Italy
[3] Assoc IST EURATOM, CFN, P-1049001 Lisbon, Portugal
[4] Univ Politecn Madrid, Grp Invest Instrumentac & Acust Aplicada, Madrid 28031, Spain
[5] UKAEA Euratom Fus Assoc, Culham Sci Ctr, Abingdon, Oxon, England
[6] ENEA Fus, EURATOM Assoc, CR Frascati, I-00044 Frascati, Italy
[7] Max Planck Inst Plasma Phys, EURATOM Assoc, Teilinst Greifswald, D-17491 Greifswald, Germany