1. Institute for Fusion Studies, Department of Physics, University of Texas at Austin, 2515 Speedway, Austin Texas, 78712, USA
2. General Atomics, 3550 General Atomics Ct., San Diego, California 92121, USA
3. University of California, Los Angeles, Los Angeles, California 90005, USA
4. University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
5. Institut für Plasmaforschung, Universität Stuttgart, 70569 Stuttgart, Germany
6. York Plasma Institute, Department of Physics, University of York, Heslington, York YO10 5DD, United Kingdom