1. Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
2. University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
3. Equipo de Propulsión Espacial y Plasmas, Universidad Carlos III de Madrid, Leganés 28911, Spain
4. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
5. Department of Aerospace Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
6. CNR-Institute for Plasma Science and Technology, via Amendola 122/D, 70126 Bari, Italy
7. LAPLACE, Université de Toulouse, CNRS, INPT, UPS, 118 Route de Narbonne, 31062 Toulouse, France
8. ICARE, Electric Propulsion Team, Centre National de la Recherche Scientifique, 45071 Orléans, France
9. Laboratoire de Physique des Plasmas, CNRS, Ecole Polytechnique, Sorbonne Université, 91120 Palaiseau, France
10. George Washington University, Washington, DC 20052, USA
11. Stanford University, Stanford, California 94305-3032, USA
12. Khristianovich Institute of Theoretical and Applied Mechanics RAS, Novosibirsk 630090, Russia
13. PlasmaPotential, Entry 29, 5/1 Moore Street, Canberra, ACT 2601, Australia
14. University of Greifswald, Greifswald D-17487, Germany
15. Space Plasma, Power and Propulsion Laboratory, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 2601, Australia
16. Holon Institute of Technology, Holon 58102, Israel