1. V.N. Karazin Kharkiv National University, Svobody sq., 4, 61022 Kharkiv, Ukraine
2. Plasma Technology Research Center, National Fusion Research Institute, 54004 Gunsan, South Korea
3. Karlsruhe Institute of Technology, IHM and IHE, Kaiserstr. 12, 76131 Karlsruhe, Germany