1. Dutch Institute for Fundamental Energy Research, 5612 AJ Eindhoven, The Netherlands
2. Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
3. Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712, USA
4. University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
5. University of Alberta, Edmonton T6G 2E1, Canada
6. MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
7. Max-Planck-Institut für Plasmaphysik, 85748 Garching, Germany
8. Lawrence Livermore National Laboratory, Livermore, California 94550, USA