[1] Univ Sheffield, Sch Math & Stat, Solar Phys & Space Plasma Res Ctr SP2RC, Sheffield S3 7RH, S Yorkshire, England
[2] Queens Univ, ARC, Sch Math & Phys, Belfast BT7 1NN, Antrim, North Ireland
[3] Univ Sci & Technol China, Dept Geophys & Planetary Sci, CAS Key Lab Geospace Environm, Hefei 230026, Anhui, Peoples R China
[4] CAS Ctr Excellence Comparat Planetol, Hefei 230026, Anhui, Peoples R China
[5] Eotvos Lorand Univ, Dept Astron, Pazmany P Setany 1-A, H-1117 Budapest, Hungary