1. HRS Fusion, West Orange, New Jersey 07052, USA
2. CEA, IRFM, F-13108 Saint-Paul-lez-Durance, France
3. Princeton Plasma Physics Laboratory, Princeton, New Jersey 08570, USA
4. Consorzio RFX and Istituto Gas Ionizzati del C.N.R., 35127 Padua, Italy