1. INFN-LNL, v.le dell’Universitá 2, 35020 Legnaro (PD), Italy
2. Consorzio RFX, c. Stati Uniti 4, 35127 Padova, Italy
3. CNR-Istituto Scienza e Tecnologia dei Plasmi, c. Stati Uniti 4, 35127 Padova, Italy
4. Univ. Milano and INFN-MI, v. Celoria 16, 20133 Milano, Italy
5. INFN-BA, v. Orabona 4, 70126 Bari, Italy
6. ITER-Organization, 13067 St. Paul Lez Durance Cedex, France