1. Max-Planck-Institut für Plasmaphysik, Greifswald, Garching, Germany
2. Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry CV4 7AL, United Kingdom
3. Culham Centre for Fusion Energy, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB, United Kingdom
4. Hochschule Stralsund, Stralsund, Germany
5. Department of Physics, Technical University of Denmark, Kgs., Lyngby, Denmark