Dorota Tomaszewska, Olga Szewczyk, Wroclaw University of Science and Technology, Wroclaw, Poland Sarah-Johanna Klose, Leibniz Institute of Plasma Physics, Greifswald, Germany Michael Stuhr, Christian-Albrechts-Universität zu Kiel, Germany Robin Delhomme, Strasbourg, France Tommi Mikkonen, Tampere University, Tampere, Finland Neven Šantić, Institute of Physics, Zagreb, Croatia Arkadiusz Tkacz, Military University of Technology, Warsaw, Poland Yuwei Jin, Radboud University Nijmegen, the Netherlands Grzegorz Kowzan, Nicolaus Copernicus University, Toruń, Poland