1. National Institute for Laser, Plasma and Radiation Physics (INFLPR), Atomiştilor Str. Nr. 409, 077125 Măgurele, Ilfov, Romania
2. University of Bucharest, Faculty of Physics, Atomistilor Str. Nr. 405, 077125 Măgurele, Romania
3. Department of Physics, Politehnica University, 313 Splaiul Independenţei, RO-060042 Bucharest, Romania
4. Joint Institute for High Temperatures, Russian Academy of Sciences, Izhorskaya Str. 13, Bd. 2, 125412 Moscow, Russia