1. Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, USA
2. General Electric Global Research Center, Niskayuna, NY, USA
3. Consiglio Nazionale delle Ricerche, Istituto Sistemi Complessi (CNR-ISC), Sesto Fiorentino (FI), Italy
4. Japan Atomic Energy Agency Tokai-mura, Naka-gun Ibaraki, Japan