Application of Gkeyll code in the simulation of ISR spectra

Incoherent scattering radars (ISRs) play a crucial role in estimating ionospheric parameters by observing electron density fluctuations. Although ISR theory has previously been addressed by simulations with a particle approach (PIC simulations) to capture the ISR spectrum, this study explores the computational capabilities of the Gkeyll code developed by the Princeton Plasma Physics Laboratory. Gkeyll employs a continuum approach in plasma simulation, providing a new perspective to obtain the ISR spectrum and study its behavior according to ISR theory.

This study conducts simulations of ionospheric plasmas with and without collisions using a Maxwellian-type distribution function. Spectral analysis of electron density perturbations is carried out to obtain the ISR spectrum of plasma waves. Additionally, we explore Gkeyll simulations of non-Maxwellian plasmas representing certain F-region processes in the ionosphere to study ISR spectrum divergence from the standard.

Comparative analyses with ISR theory models and previous PIC simulations reveal Gkeyll's ability to capture the ISR spectra consistently with analytical theory. Moreover, our results suggest Gkeyll's potential to explore interparticle collisions, non-linear Landau Damping effects, and alternative distribution functions, thus extending ISR theory. This work validates Gkeyll's efficacy in ISR spectrum simulation and offers future directions for its application in exploring complex ionospheric phenomena.