In this study, we investigate the global ionospheric impact of high‐speed solar wind streams/corotating interaction regions (HSS/CIR). A series of 10 such events are identified between December 1, 2007 and April 29, 2008, characterized in the frequency domain by the main spectral peaks corresponding to 27, 13.5, 9, and 6.75 days. The spectra of solar wind magnetic field, speed, and proton density, as well as those of the geomagnetic indices AE and SYM‐H, are solely dominated by these features. By contrast, the ionospheric NmF₂ and to a lesser extent the hmF₂ spectra have a much more complex structure, with secondary peaks adding to or replacing the main ones. We argue that this is evidence of the nonlinear nature of the magnetosphere‐ionosphere coupling, highlighted particularly in the NmF₂ ionospheric response. Additionally, we show that hmF₂ is more closely correlated than NmF₂ to all parameters describing the solar wind and geomagnetic activity. Finally, the ionospheric response shows a higher correlation with B_z than any other solar wind parameter, and higher with SYM‐H than AE, indicating that for the low‐frequency part of the spectrum, high‐latitude Joule heating and particle precipitation play a secondary role to that of prompt penetration electric fields in dictating the ionospheric response to geomagnetic activity, in the case of this sequence of HSS/CIR events.

中文翻译：

---

2007-2008年太阳最低值期间全球电离层对HSS / CIR事件周期序列的响应

在这项研究中，我们调查了高速太阳风/旋转相互作用区域（HSS / CIR）对全球电离层的影响。在2007年12月1日至2008年4月29日之间，确定了一系列10次此类事件，其特征是在频域中对应于27、13.5、9和6.75天的主频谱峰值。太阳风磁场，速度和质子密度的频谱以及地磁指数AE和SYM-H的频谱仅受这些特征支配。相比之下，电离层NmF ₂和较小程度的hmF ₂光谱的结构要复杂得多，次级峰会增加或替代主峰。我们认为这是磁层-电离层耦合非线性性质的证据，尤其是在NmF ₂电离层响应中尤为突出。此外，我们显示hmF ₂比NmF ₂与描述太阳风和地磁活动的所有参数的相关性更高。最后，电离层响应显示出与B _z更高的相关性 比任何其他太阳风参数都高，并且SYM‐H比AE高，这表明在频谱的低频部分，高纬度焦耳加热和粒子沉淀在指示瞬态电场方面起次要作用。在这种HSS / CIR事件序列的情况下，电离层对地磁活动的响应。