Abstract. Auroral kilometric radiation (AKR) is a terrestrial radio emission excited by the same accelerated electrons which excite auroral emissions. Although it is well correlated with auroral and geomagnetic activity, the coupling timescales between AKR and different magnetospheric or ionospheric regions have yet to be determined. Estimation of these coupling timescales is non-trivial as a result of complex, non-linear processes which rarely occur in isolation. In this study, the mutual information between AKR intensity and different geomagnetic indices is used to assess the correlation between variables. Indices are shifted to different temporal lags relative to AKR intensity, and the lag at which the variables have the most shared information is found. This lag is interpreted as the coupling timescale. The AKR source region receives the effects of a shared driver before the auroral ionosphere. Conversely, the polar ionosphere reacts to a shared driver before the AKR source region. Bow shock interplanetary magnetic field BZ is excited about 1 h before AKR enhancements. This work provides quantitatively determined temporal context to the coupling timelines at Earth. The results suggest that there is a sequence of excitation following the onset of a shared driver: first, the polar ionosphere feels the effects, followed by the AKR source region and then the auroral ionosphere.

中文翻译：

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使用互信息量化磁层-电离层耦合时间尺度：地面无线电发射和电离层-磁层电流的响应

摘要。极光千米辐射 (AKR) 是由激发极光发射的相同加速电子激发的地面无线电发射。尽管它与极光和地磁活动密切相关，但 AKR 与不同磁层或电离层区域之间的耦合时标尚未确定。由于复杂的非线性过程很少单独发生，因此对这些耦合时间尺度的估计并非易事。在本研究中，AKR强度与不同地磁指数之间的互信息用于评估变量之间的相关性。将指数转移到相对于 AKR 强度的不同时间滞后，并找到变量具有最多共享信息的滞后。该滞后被解释为耦合时间尺度。 AKR 源区域在极光电离层之前受到共享驱动器的影响。相反，极地电离层对 AKR 源区域之前的共享驱动器做出反应。弓激波行星际磁场 BZ 在 AKR 增强前约 1 小时被激发。这项工作为地球上的耦合时间线提供了定量确定的时间背景。结果表明，在共享驱动器出现后存在一系列激发：首先，极地电离层感受到影响，然后是 AKR 源区域，然后是极光电离层。