[1] Natl Fus Res Inst, Taejon 305333, South Korea
[2] Hanyang Univ, Dept Elect Engn, Seoul 133791, South Korea
[3] Univ Sci & Technol, Dept Nucl Fus & Plasma Sci, Taejon 305333, South Korea
[4] Chinese Acad Sci, Inst Plasma Phys, Hefei 230031, Peoples R China
[5] Forschungszentrum Julich, D-52428 Julich, Germany
[6] Univ Ghent, Dept Appl Phys, B-9000 Ghent, Belgium
[7] Forschungszentrum Julich, Assoc EURATOM FZJ, Trilateral Euregio Cluster, Inst Energie & Klimaforsch Plasmaphys, D-52425 Julich, Germany
[8] Charles Univ Prague, Dept Surface & Plasma Sci, CZ-18000 Prague, Czech Republic
[9] EURATOM, Dutch Inst Fundamental Energy Res DIFFER, Trilateral Euregio Cluster, NL-3430 BE Nieuwegein, Netherlands