This study aims to investigate the effects of the solar activity phases on the magnetospheric processes in relation to daily relativistic electron ( E > 2 $E>2$ MeV) dynamics at geosynchronous orbit (GEO) during Solar Cycles 23–24. GOES observations indicate that in the descending phase the electron fluxes are seasonally dependent with largest flux in equinoctial periods, relatively high, and 27-day recurrent, while in the maximum phases they are relatively low and nonrecurrent. The electron fluxes are relatively low and partially recurrent in the ascending phases. The cross correlation coefficients (c.c.s) of daily K p $K_{\textrm{p}}$ – V sw $V_{\textrm{sw}}$ , K p $K_{\textrm{p}}$ – A E $AE$ , K p $K_{\textrm{p}}$ – A L $AL$ evolve in the similar trend for both solar cycles: highest during the descending phases, lower in the ascending phases, and lowest in the maximum and minimum phases. The correlation of K p $K_{\textrm{p}}$ –viscous term is strongest during descending phases and weakest around the maximum phases. The correlation of K p $K_{\textrm{p}}$ –merging term slightly varies in a chaotic way from one solar phase to another, but drops to its lowest value in the solar minimum. The correlation analysis results signify the role of the solar activity in controlling the solar wind–magnetosphere couplings. Two case studies during maximum (2000) and descending (2017) phases indicate that the solar activity dependence of the magnetospheric processes and relativistic electrons is characterized by substorm activity and solar wind drivers. Most of the substorms induced by coronal mass ejections in the maximum phase exhibit strong but short and non-repetitive features that associate with low electron fluxes at GEO. In contrast, high intensity, prolonged, and repetitive substorm activities induced by high-speed solar winds are the main cause of the relativistic electron enhancements during the descending phases. The enhancements strongly depend on V sw $V_{\textrm{sw}}$ and Σ K p $\Sigma K_{\textrm{p}}$ in which only appropriate V sw $V_{\textrm{sw}}$ and Σ K p $\Sigma K_{\textrm{p}}$ are required. In the descending phase, the requirements for the flux enhancements to ≥ 10 3 $\geq 10^{3}$ cm −2 sr −1 s −1 are the simultaneity of V sw > 500 $V_{\textrm{sw}}>500$ km/s and the prolongation of Σ K p > 220 $\Sigma K_{\textrm{p}}>220$ and to ≥ 10 4 $\geq 10^{4}$ cm −2 sr −1 s −1 when V sw ≥ 630 $V_{\textrm{sw}}\geq 630$ km/s and Σ K p > 227 $\Sigma K_{\textrm{p}}>227$ . Furthermore, the correlations of Σ K p $\Sigma K_{\textrm{p}}$ and log-electron fluxes are stronger in the descending/ascending phases than in the maximum phase, while the time lag between them is longer in the maximum phase. The remarkable correlations of V sw $V_{\textrm{sw}}$ – K p $K_{\textrm{p}}$ and in the descending phase indicate appropriate magnetospheric convection in association with the repetitive substorms that can effectively trigger the stochastic mechanisms of electron acceleration. The results are extensively discussed in the light of observations and current theories of radiation belt dynamics.

中文翻译：

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地球静止轨道上磁层过程和相对论电子通量的太阳活动相位依赖性

本研究旨在研究太阳活动阶段对磁层过程的影响，这些过程与太阳周期 23-24 期间地球同步轨道 (GEO) 的日常相对论电子 (E > 2 $E>2$ MeV) 动力学有关。GOES 观测表明，在下降阶段，电子通量具有季节性依赖性，在分界线期间通量最大，相对较高，27 天反复，而在最大阶段，它们相对较低且不反复。电子通量相对较低，并且在上升相中部分循环。每日 K p $K_{\textrm{p}}$ – V sw $V_{\textrm{sw}}$ , K p $K_{\textrm{p}}$ – AE $ 的互相关系数（ccs） AE$ , K p $K_{\textrm{p}}$ – AL $AL$ 在两个太阳周期的演化趋势相似：在下降阶段最高，在上升阶段较低，在最大和最小阶段最低。K p $K_{\textrm{p}}$ – 粘性项的相关性在下降阶段最强，在最大阶段附近最弱。K p $K_{\textrm{p}}$ - 合并项的相关性从一个太阳相到另一个太阳相以混乱的方式略有变化，但在太阳极小期下降到最低值。相关分析结果表明太阳活动在控制太阳风-磁层耦合中的作用。最大值 (2000) 和下降 (2017) 阶段的两个案例研究表明，磁层过程和相对论电子对太阳活动的依赖性以亚暴活动和太阳风驱动因素为特征。大多数由最大相位日冕物质抛射引起的亚暴表现出强烈但短暂且不重复的特征，这与 GEO 处的低电子通量有关。相比之下，由高速太阳风引起的高强度、长时间和重复的亚暴活动是下降阶段相对论电子增强的主要原因。增强强烈依赖于 V sw $V_{\textrm{sw}}$ 和 Σ K p $\Sigma K_{\textrm{p}}$ 其中只有合适的 V sw $V_{\textrm{sw}}$ 和Σ K p $\Sigma K_{\textrm{p}}$ 是必需的。在下降阶段，通量增强到 ≥ 10 3 $\geq 10^{3}$ cm -2 sr -1 s -1 的要求是 V sw > 500 $V_{\textrm{sw}} >500$ km/s 和 Σ K p 的延长 > 220 $\Sigma K_{\textrm{p}}> 220$ 和 to ≥ 10 4 $\geq 10^{4}$ cm −2 sr −1 s −1 当 V sw ≥ 630 $V_{\textrm{sw}}\geq 630$ km/s 和 Σ K p > 227 $\Sigma K_{\textrm{p}}>227$。此外，Σ K p $\Sigma K_{\textrm{p}}$ 与对数电子通量的相关性在下降/上升阶段比在最大阶段更强，而在最大阶段它们之间的时间滞后更长阶段。V sw $V_{\textrm{sw}}$ – K p $K_{\textrm{p}}$ 与下降阶段显着的相关性表明适当的磁层对流与重复亚暴相关，可以有效触发随机电子加速机制。根据辐射带动力学的观察和当前理论，对结果进行了广泛的讨论。227 $\Sigma K_{\textrm{p}}>227$。此外，Σ K p $\Sigma K_{\textrm{p}}$ 与对数电子通量的相关性在下降/上升阶段比在最大阶段更强，而在最大阶段它们之间的时间滞后更长阶段。V sw $V_{\textrm{sw}}$ – K p $K_{\textrm{p}}$ 与下降阶段显着的相关性表明适当的磁层对流与重复亚暴相关，可以有效触发随机电子加速机制。根据辐射带动力学的观察和当前理论，对结果进行了广泛的讨论。227 $\Sigma K_{\textrm{p}}>227$。此外，Σ K p $\Sigma K_{\textrm{p}}$ 与对数电子通量的相关性在下降/上升阶段比在最大阶段更强，而在最大阶段它们之间的时间滞后更长阶段。V sw $V_{\textrm{sw}}$ – K p $K_{\textrm{p}}$ 与下降阶段显着的相关性表明适当的磁层对流与重复亚暴相关，可以有效触发随机电子加速机制。根据辐射带动力学的观察和当前理论，对结果进行了广泛的讨论。而在最大阶段，它们之间的时间滞后更长。V sw $V_{\textrm{sw}}$ – K p $K_{\textrm{p}}$ 与下降阶段显着的相关性表明适当的磁层对流与重复亚暴相关，可以有效触发随机电子加速机制。根据辐射带动力学的观察和当前理论，对结果进行了广泛的讨论。而在最大阶段，它们之间的时间滞后更长。V sw $V_{\textrm{sw}}$ – K p $K_{\textrm{p}}$ 与下降阶段显着的相关性表明适当的磁层对流与重复亚暴相关，可以有效触发随机电子加速机制。根据辐射带动力学的观察和当前理论，对结果进行了广泛的讨论。