A Long-Term Study of the Variability of Polar Cap Patches Using Advanced Modular Incoherent Scatter Radars (AMISRs)

The polar cap ionosphere is a dynamic and intricately structured environment that plays host to polar cap patches (PCPs) and other mesoscale density formations. These phenomena can lead to the emergence of smaller-scale structures through various plasma instability mechanisms. Existing literature highlights substantial variability in the occurrence, density, and characteristics of PCPs influenced by solar and geomagnetic conditions. However, a comprehensive statistical analysis utilizing long-term data is lacking, particularly from the Resolute Bay Incoherent Scatter Radar North (RISR-N). In this article, we consider 11 years of RISR-N data (≅one solar cycle) to perform an analysis of PCPs, focusing on their occurrence distributions, behavior with density, temperature, different geomagnetic indices, and characteristics over time. We show the long-term distribution of PCPs and how it varies with geomagnetic activity. We examine the role of solar activity by investigating correlations between solar activity indices (e.g., F10.7, solar wind conditions) and the occurrence of PCPs to provide a clearer picture of the influence of solar activity on patch dynamics. We identify seasonal and diurnal variability of PCPs to establish a clear understanding of how these factors influence their behavior.