1. Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching, Germany
2. Physik Department E28, Technische Universität München, 85748 Garching, Germany
3. Astro Fusion Spectre, LLC, 11263
Avenida de los Lobos, Unit D, San Diego, California 92127, USA
4. Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA