A Ray-tracing simulation of High Frequency radio wave propagation in Antarctica during the Decembere 4, 2021 total solar eclipse

High Frequency (HF) radio wave is highly sensitive to plasma density variation in the ionosphere. December 4, 2021, the total solar eclipse provides an opportunity to assess the effect of the solar eclipse on the ionospheric plasma density. A solar eclipse causes a significant reduction of the plasma temperature and plasma density, leading to a change in HF radio wave propagation condition (refractive index) in the ionosphere.
In this work, we will present ray-tracing simulations to the accepted Doppler shift of the McMurdo SuperDARN transmissions received by the Radio Receiver Instrument (RRI) onboard the Cascade Smallest and Ionospheric Polar Explorer spacecraft during the December 4 eclipse. The two time windows simulated are 6:54 to 7:04 UT and 8:39 to 8:46 UT, when e-POP passed through the region. Provision of High-Frequency Raytracing Laboratory (PHaRLAP) is used for raytracing through an ionospheric plasma density generated by the SAMI3 model. We conducted the raytracing under an eclipse and non-eclipse SAMI3 model, and derived the theoretical Doppler shift for each case. The refractive index of HF radio wave experiences in the ionosphere depends on the plasma density and collision rate of the ionosphere. Thus, the effect of the eclipse on the ionosphere will manifest in the Doppler shift pattern of SuperDARN's transmission received by RRI.