1. Leibniz Institute for Plasma Science and Technology (INP Greifswald), Felix-Hausdorf-Str. 2, 17489 Greifswald, Germany
2. Department of Physical Electronics, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic
3. LPP-CNRS, Ecole Polytechnique, 91128 Palaiseau, France
4. Department of Pulse Plasma Systems, Institute of Plasma Physics, Academy of Sciences of the Czech Republic, Za Slovankou 3, 182 00 Prague, Czech Republic