Ivarsen Magnus F, St-Maurice Jean-Pierre, Hussey Glenn, Spicher Andres, Jin Yaqi, Lozinsky Adam, Goodwin Lindsay V, Galeschuk Draven, Park Jaeheung, Clausen Lasse B N
Department of Physics, University of Oslo, Oslo, Norway.
Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, SK, Canada.
Sci Rep. 2023 Jul 18;13(1):11579. doi: 10.1038/s41598-023-38777-4.
The ionosphere, Earth's space environment, exhibits widespread turbulent structuring, or plasma irregularities, visualized by the auroral displays seen in Earth's polar regions. Such plasma irregularities have been studied for decades, but plasma turbulence remains an elusive phenomenon. We combine scale-dependent measurements from a ground-based radar with satellite observations to characterize small-scale irregularities simultaneously in the bottomside and topside ionosphere and perform a statistical analysis on an aggregate from both instruments over time. We demonstrate the clear mapping of information vertically along the ionospheric altitude column, for field-perpendicular wavelengths down to 1.5 km. Our results paint a picture of the northern hemisphere high-latitude ionosphere as a turbulent system that is in a constant state of growth and decay; energy is being constantly injected and dissipated as the system is continuously attempting an accelerated return to equilibrium. We connect the widespread irregularity dissipation to Pedersen conductance in the E-region, and discuss the similarities between irregularities found in the polar cap and in the auroral region in that context. We find that the effects of a conducting E-region on certain turbulent properties (small-scale spectral index) is near ubiquitous in the dataset, and so we suggest that the electrodynamics of a conducting E-region must be considered when discussing plasma turbulence at high latitudes. This intimate relationship opens up the possibility that E-region conductivity is associated with the generation of F-region irregularities, though further studies are needed to assess that possibility.
电离层作为地球的空间环境，呈现出广泛的湍流结构，即等离子体不规则性，这可通过地球极地地区出现的极光显示观察到。此类等离子体不规则性已被研究数十年，但等离子体湍流仍是一个难以捉摸的现象。我们将地基雷达的尺度相关测量结果与卫星观测数据相结合，以同时表征电离层底部和顶部的小尺度不规则性，并对两种仪器随时间的总体数据进行统计分析。我们证明了对于低至1.5千米的场垂直波长，信息可沿电离层高度柱进行清晰的垂直映射。我们的研究结果描绘出一幅北半球高纬度电离层的图景，它是一个处于持续生长和衰退状态的湍流系统；随着系统不断试图加速恢复平衡，能量不断被注入和耗散。我们将广泛存在的不规则性耗散与E区的佩德森电导率联系起来，并在此背景下讨论极盖区和极光区发现的不规则性之间的相似性。我们发现，导电E区对某些湍流特性（小尺度谱指数）的影响在数据集中几乎无处不在，因此我们建议在讨论高纬度地区的等离子体湍流时，必须考虑导电E区的电动力学。这种密切关系揭示了E区电导率与F区不规则性产生相关的可能性，不过还需要进一步研究来评估这种可能性。
