The potential of HamSCI Doppler Observations for inferring Solar Flare Effects on the Ionosphere

A solar flare is a space weather event that causes a transient in the ionospheric system at sub-auroral, middle, and lower latitudes, commonly known as the solar flare effect (SFE). Sudden enhancement in high-frequency (HF) absorption is a well-known impact of solar flare-driven Short-Wave Fadeout (SWF). Less understood, is a perturbation of the radio wave frequency as it traverses the lower ionosphere in the early stages of SWF, also known as the Doppler flash. SuperDARN radar network is typically used to study the Doppler flash. Previous investigations have suggested two possible sources that might contribute to the manifestation of Doppler flash: first, enhancements of plasma density in the D and lower E-regions; second, the lowering of the reflection point in the F-region. HamSCI is a platform that publicizes and promotes scientific research and understanding through amateur radio activities in the HF band. Studies have shown that solar flare-driven HF absorption can affect amateur radio signal strength. Recent development showed that the HamSCI Doppler observations can provide insight into the physics behind changes in phase path length of the trans ionospheric radio signals. In this study, we will demonstrate how HamSCI Doppler observations can be used to infer flare-driven changes in the ionospheric properties and associated Doppler flash. Furthermore, if successful the study will also quantify Doppler flash recorded in HamSCI as a function of flare strength, flare location on the solar disk, operating frequency, and location on the Earth. Upon successful quantification of Doppler flash, we will compare its properties with previous studies that used SuperDARN observations.