One of the most striking properties of Kinetic Alfvén Waves (KAW) is that, unlike the also Alfvénic Electromagnetic Ion Cyclotron (EMIC) waves, these waves are right-hand polarized in the plasma frame. In particular, this signature property is key for the identification of KAW from in situ measurements of plasma waves. From the theoretical point of view, both the dispersion relation and the polarization of KAW has been mostly studied in proton–electron plasmas. However, most astrophysical and space plasmas are multi-species, and therefore in these systems the dispersion properties of the KAW may not depend only on the macroscopic parameters of proton and electron distributions, but also on the parameters of heavier ions. Here, using Vlasov linear theory we study the dispersion properties of Alfvénic modes in multi-species plasmas composed by electrons, protons, and O${}^{+}$ ions, with macroscopic plasma parameters relevant to the inner magnetosphere. In consistency with recent observations, our numerical results show that the presence of O${}^{+}$ ions allows the existence of KAW in a wider wave-number range and at smaller wave-normal angles compared to the electron–proton case, but at the same time isotropic O${}^{+}$ ions tend to reduce (or even inhibiting) the growth rates of unstable KAW triggered by anisotropic protons. These results suggest that magnetospheric ions may play an important role on the energy transfer from large macroscopic scales to sub-ionic and electronic scales, especially during intense geomagnetic storms in which O${}^{+}$ ions can dominate the plasma composition in the inner magnetosphere.

动力学Alfvén波（KAW）最引人注目的特性之一是，与Alfvénic电磁离子回旋加速器（EMIC）波不同，这些波在等离子体框架中是右旋极化的。特别地，该签名特性是从等离子体波的现场测量中识别KAW的关键。从理论的角度来看，KAW的色散关系和极化都主要在质子-电子等离子体中进行了研究。但是，大多数天体等离子体和空间等离子体是多物种的，因此在这些系统中，KAW的分散特性可能不仅取决于质子和电子分布的宏观参数，而且取决于重离子的参数。这里，${}^{+}$离子，具有与内部磁层有关的宏观等离子体参数。与最近的观察结果一致，我们的数值结果表明，O的存在${}^{+}$ 与电子-质子的情况相比，离子允许在更宽的波数范围和更小的波法向角存在KAW，但同时各向同性O${}^{+}$离子倾向于降低（甚至抑制）各向异性质子触发的不稳定KAW的生长速率。这些结果表明，磁层离子可能在从大的宏观尺度到亚离子尺度和电子尺度的能量转移中起重要作用，特别是在强烈的地磁风暴中，${}^{+}$ 离子可以控制内部磁层中的等离子体组成。