[1] Natl Res Nucl Univ MEPhI, Moscow 115409, Russia
[2] Royal Inst Technol KTH, Stockholm 10044, Sweden
[3] Max Planck Inst Plasma Phys, D-85748 Garching, Germany
[4] NILARP, Assoc EURATOM MEdC, Bucharest, Romania
[5] Culham Sci Ctr, EURATOM UKAEA Fusion Assoc, Abingdon 0X14 3DB, Oxon, England
[6] Culham Sci Ctr, JET EFDA, Abingdon 0X14 3DB, Oxon, England