1. Department of Physics, Sapienza, Universitá di Roma, P.le A. Moro 5, I-00185 Roma, Italy
2. Institute of Space Sciences (ICE, CSIC) & Institut d’Estudis Espacials de Catalunya (IEEC) at Campus UAB, Carrer de Can Magrans, s/n, E-08193 Barcelona, Spain
3. Institute of Applied Mathematics, Academy of Mathematics and Systems Science, CAS, Beijing 100190, China
4. Kavli Institute for Astronomy and Astrophysics, Beijing 100871, China
5. Zentrum für Astronomie und Astrophysik, TU Berlin, Hardenbergstraße 36, D-10623 Berlin, Germany
6. Astronomisches Rechen-Institut, Mönchhofstraße 12-14, D-69120 Heidelberg, Germany
7. Hebrew University of Jerusalem, Racah Institute of Physics, Givat Ram, 9190401 Jerusalem, Israel