1. Solar Technology Laboratory, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
2. PROMES-CNRS, F-66120 Font Romeu Odeillo, France
3. Solar Research Unit, The Weizmann Institute of Science, IL-76100 Rehovot, Israel
4. Scanarc Plasma Technologies AB, S-81321 Hofors, Sweden
5. Department of Mechanical and Process Engineering, ETH Zurich, CH-8092 Zurich, Switzerland