| Περίληψη: |
Solar wind (SW) entry into the magnetosphere occurs through several mechanisms, but their dependence on the properties of different ion species is unknown. We compare measurements from Wind‐STICS (magnetosphere) with ACE‐SWICS (L1) to test for any preferential entry between He2+ and SW heavy ions. We utilize a scaling factor, χ $\chi $, between upstream and magnetospheric measurements of [nO6+ ${\mathrm{n}}_{{\mathrm{O}}^{6+}}$ + nC5+ ${\mathrm{n}}_{{\mathrm{C}}^{5+}}$ + nFe10+ ${\mathrm{n}}_{{\mathrm{Fe}}^{10+}}$]/nHe2+ ${\mathrm{n}}_{{\mathrm{He}}^{2+}}$. We analyze χ $\chi $'s variation for different upstream conditions: IMF, NSW, PDyn, and VSW. Our results reveal that χ $\chi $ ∼ 1 during strong driving, but >1 during weak driving, meaning that heavier SW ions enter the magnetosphere more efficiently than He2+.We suggest this is due to their larger gyroradii. Plain Language Summary: Earth's space environment is populated by positively charged particles known as "ions" that come from two main sources: the Sun and the Earth. Although most of its composition is protons, heavier and higher charge‐state elements like helium, oxygen, carbon, and iron ions also contribute to the hot, electrically‐charged particles in near‐Earth space. During 1998–2002, the solar wind's heavier ions were observed by a spacecraft called "Wind" near‐Earth and by another spacecraft called "ACE" in interplanetary space. We study how the density ratio between different solar wind heavy‐ions observed by these two spacecrafts changes as the ions cross the near‐Earth space boundary, and how this varies under different conditions, such as the density, pressure, and speed of the solar wind, and the orientation of the magnetic field originating from the Sun. We find that oxygen, carbon, and iron ions enter near‐Earth space more preferentially than helium during weak conditions. Our results, therefore, reveal that the properties of the solar wind ion species (such as their mass and/or charge) are important while crossing into our space environment. Key Points: Wind‐ACE ion measurements yield a scaling factor enabling statistical assessment of solar‐wind (SW) entrySW heavy ions enter the magnetosphere more efficiently than alphas under weak driving, but entry becomes comparable when driving is strongSW ion entry to the magnetosphere may have a mass‐per‐charge dependence during weak driving, with high m/q ions entering more efficiently [ABSTRACT FROM AUTHOR] |