An examination of geomagnetic data collected in Davo, Philippines, over a 20-year period encompassing solar cycles 23 and 24 resulted in the identification of attributes linked to the Inter-Hemispheric Field-Aligned Currents (IHFACs). The study focused on the analysis of the normalized D component of geomagnetic field (ΔD). Specifically, characteristics were investigated in the dawn, noon, and dusk sectors, revealing the identification of both long-term features across solar cycle 23 and 24. During the declining phases of solar cycles, peak-to-peak amplitudes of ΔD in the dusk sector show enhancements, indicating increased sensitivity to geomagnetic variations as solar activity wanes. The variation of ΔD during storm periods was studied and compared to quiet time ΔD variations to identify the changes in IHFACs during high-intensity geomagnetic storms. During the main phase of severe geomagnetic storms, significant enhancements in the negative component of ΔD occur around local noon, while at night, the positive component of ΔD shows marked increases. During the recovery phase, the positive component's daily amplitude gradually decreases over several days, indicating a slow return to quieter geomagnetic conditions, whereas the negative component remains relatively stable compared to quiet periods. It is evident that the response of IHFACs to solar disturbances significantly depends on the phase of the geomagnetic storm and the time of day. © The Author(s) 2026.

Low Earth Orbit (LEO) satellite networks, represented by Starlink, have rapidly advanced as communication solutions for unconnected regions and during disaster scenarios. However, related studies have reported that communication via Starlink experiences significant performance degradation due to link quality fluctuations caused by frequent handovers. Moreover, since Starlink employs a proprietary communication system, existing research has mainly focused on end-to-end performance evaluation, while its internal route selection mechanisms remain undisclosed. To address this, we simulate both current and future Starlink environments using the ns-3 LEO module and evaluate the impact of satellite selection methods on communication performance in LEO satellite networks. This study proposes a satellite selection method that predicts the satellite trajectory based on the variation in RTT, enabling the selection of satellites capable of providing longer communication durations. The effectiveness of the proposed method is verified using two key performance metrics: communication duration per satellite and route establishment success rate, which have been challenges in previous studies. As a result, the proposed method demonstrated up to 98.4% of the theoretical maximum performance, achieving both stable route establishment and extended communication duration. © 2013 IEEE.