1. Wigner Research Centre for Physics, Budapest, Hungary
2. Graz University of Technology, Graz, Austria
3. Budapest University of Technology and Economics, Budapest, Hungary
4. Széchenyi University, Győr, Hungary
5. Institute for Plasma Physics, Czech Academy of Sciences, Prague, Czech Republic
6. Institute for Plasma Physics, Chinese Academy of Sciences, Hefei, China
7. Max Planck Institute for Plasma Physics, Greifswald, Germany