1. Institute for the Study of Earth, Oceans, and Space University of New Hampshire Durham NH USA
2. College Brook Scientific Durham NH USA
3. Department of Physics University of New Hampshire Durham NH USA
4. Bradley Department of Electrical and Computer Engineering Virginia Polytechnic Institute and State University Blacksburg VA USA
5. Now at Langley Research Center National Aeronautics and Space Administration Hampton VA USA
6. Space Sciences Laboratory University of California Berkeley CA USA