Fig. 4. Comparison of Arase and MMS measurements with solar wind composition.

a, b Total and Bz component of the interplanetary magnetic field (IMF) from the OMNI dataset, propagated to the location of the Earth Bow Shock. c SYM-H index, d–g Arase H⁺ and O⁺ Differential Flux, covering the range from 1–180 keV per q. h H⁺, O^+, and He⁺⁺ density at Arase integrated over the energy range 1–180 keV per q. i, j H⁺ and O⁺ differential flux at MMS. k H⁺, O⁺ and He⁺⁺ Density at MMS. l He⁺⁺/H⁺ density ratio, from Wind/SWE (black), MMS (red), and Arase (blue). The color bar at the bottom identifies the dominant source of the plasma in each location: solar wind (orange), polar wind (blue), and cusp or nightside auroral (green). The two cusp or auroral source time periods in orbit 4 are also indicated with green vertical lines.