1. Laboratoire de Physique des Gaz et Plasmas-LPGP, UMR 8578 CNRS,
Université Paris–Sud, Université Paris–Saclay, 91405 Orsay
Cedex, France
2. Department of Space and Plasma Physics, School of Electrical Engineering,
KTH-Royal Institute of Technology, SE-100 44 Stockholm,
Sweden
3. Science Institute, University of Iceland,
Dunhaga 3, IS-107 Reykjavik, Iceland
4. Plasma and Coatings Physics Division, IFM-Materials Physics,
Linköping University, SE-581 83 Linköping,
Sweden