Simulation Study of the Interaction Between Electromagnetic Waves and Ionosphere During Parametric Decay Instability (PDI) Process

摘要

In this study, based on the two-fluid magnetohydrodynamics (MHD) theory, the advanced finite-difference time-domain method have been conducted to successfully simulate the variability in the electric field, magnetic field and plasma number density during the parametric decay instability (PDI) process driven by electromagnetic (EM) waves. As a result, the mode-conversion process of Langmuir waves excited by ordinary mode EM waves was visualized at the turning point at the millisecond timescale, which is an important characteristic of the PDI process. It was found that the ionospheric electron number density rapidly oscillates with the high-frequency (HF) Langmuir waves. Ionospheric ion density depletion was also observed at the cutoff altitude and two ion density peaks were simultaneously observed on both sides of the EM wave reflection region. These results are of benefit to understand the nonlinear interaction between EM waves and the ionosphere.