A two-dimensional numerical simulation of polarization electric field instability in the mid-latitude ionospheric E region at Wuhan, China

Background Ionospheric E-region irregularities modify local electron density and can affect high-frequency radio propagation, satellite communication, and navigation. Existing theories describe plasma density perturbations produced by electron density gradients and electric fields in sporadic E (ES) layers, but do not fully explain the persistence, propagation direction, and spatial structure of quasi-periodic (QP) echoes. Objective This study investigates the generation and evolution of E-region irregularities under geomagnetic conditions representative of the mid-latitude region at Wuhan. Methods A two-dimensional numerical simulation of E-region polarization electric field instability is conducted with initial perturbations and zonal wind shear. The Flux-Corrected Transport (FCT) and Bi-conjugate Gradient Stabilized (BICGSTAB) methods are used to solve the governing equations. The nighttime irregularity evolution at 100 km is simulated under a specified ionospheric background condition. Results The simulated plasma-density structures and polarization electric fields evolve in space and time. Horizontally distributed ES structures extend along the geomagnetic field and develop into stripe-like thin layers. During the 1,500 s simulation, the maximum polarization electric field reaches approximately 2.2 mV/m. The characteristic spacing of the resulting structures is comparable to the 27.0 km horizontal wavelength of the imposed seeding perturbation. Conclusion Under the prescribed background and perturbation conditions, the simulated ES morphology is associated with the imposed perturbation scale, suggesting a possible link between seeding wavelength and the resulting structure.