A 2D Numerical Study of the Langmuir Parametric Instability in the Ionospheric Modification

Parametric Decay Instability (PDI) plays an important role in the interaction of the high-power HF EM waves with ionosphere plasma. In this study, we have constructed a 2D numerical simulation model for studying PDI with a nearly realistic ionosphere background and a radio wave propagation model by taking a proper processing for the routine dynamic equations of plasma with generalized Zakharov method. The simulation results found that high-power HF EM waves could excite two electrostatic modes of a Langmuir wave and an ion acoustic wave near the reflection point of the ordinary wave (O-mode) within a timescale order of millisecond. The amplitude of density perturbation grows exponentially and significantly influencing the plasma frequency related to `low frequency' density background. These processes are also followed by plasma caviton structures and trapped Langmuir waves. Finally, the O-mode heating leads to an intense localized turbulence. This paper also presents the simulation results of Langmuir parametric instability (LPI) excited by powerful HF wave heating at the O-mode reflection height. The study of this article contributes to formation of a deep impression for the physical mechanism of the Parametric Decay Instability (PDI). It is also helpful to research on the nonlinear interaction between the high-power HF EM waves and ionosphere plasma.