1. Swedish Institute of Space Physics Kiruna Sweden
2. Division of Space TechnologyLuleå University of Technology Kiruna Sweden
3. Department of PhysicsUmeå University Umeå Sweden
4. Space and Plasma Physics, School of Electrical EngineeringRoyal Institute of Technology Stockholm Sweden
5. Laboratory for Atmospheric and Space Physics Boulder Colorado USA
6. Royal Belgian Institute for Space Aeronomy Brussels Belgium
7. Swedish Institute of Space Physics Uppsala Sweden