A review of the impact of the cold-ion and cold-electron populations in the Earth’s magnetosphere is presented. The cold populations are defined by total energy less than approximately 100 eV, i.e. in the energy range which is strongly affected by spacecraft charging and that often dominates the total plasma density. We also include the warm plasma cloak in the review, since it overlaps partially with the cold energy range and is a population that is still not well understood.

The known impacts of cold ions and cold electrons that are discussed are: the source of hot magnetospheric plasma, solar-wind/magnetosphere coupling, magnetotail reconnection and substorms, Kelvin–Helmholtz instabilities on the magnetopause, chorus, hiss, electromagnetic-ion-cyclotron and ultra-low-frequency wave–particle interactions, aurora structuring and spacecraft charging. Other possible impacts are associated with refilling on open-drift trajectories, the remnant layer and plasmapause disruption. A discussion of the difficulty of cold-plasma measurements and the need for new measurement techniques that measure the full cold-ion and cold-electron distribution functions is also presented.

There remain a lot of unknowns about the cold-ion and cold-electron populations, associated with their origin, properties, drivers and impacts. These populations will need to be fully understood before the magnetosphere–ionosphere system can be fully understood.

本文介绍了冷离子和冷电子种群对地球磁层的影响。冷态的总能量定义为小于约100 eV的能量，即在能量范围内，该能量范围受航天器充电的强烈影响，并且通常在总等离子体密度中占主导地位。我们还将温暖的等离子体披风也包含在本评论中，因为它与冷能范围部分重叠，并且是一个尚不为人所知的种群。

讨论的冷离子和冷电子的已知影响是：磁层热等离子体的来源，太阳风/磁层耦合，磁尾重连和亚暴，对磁层顶的开尔文-亥姆霍兹不稳定性，合唱，嘶嘶声，电磁离子回旋加速器以及超低频波与粒子的相互作用，极光结构和航天器的充电。其他可能的影响与对开式漂移轨迹的补充，残余层和血浆停顿有关。还讨论了冷等离子体测量的困难以及对测量完整的冷离子和冷电子分布函数的新测量技术的需求。

关于冷离子和冷电子种群，与它们的起源，性质，驱动因素和影响有关，还有许多未知数。在完全理解磁层-电离层系统之前，需要对这些种群有充分的了解。