Simulation of localized electron density enhancement caused by high-pressure H₂O gas release in ionosphere

Based on the continuity and momentum equations, a self-consistent simulation model is developed for describing the localized electron density enhancement caused by high-pressure H2O gas release in the ionosphere. The chemical reaction and momentum exchange process between the neutral gas and ionospheric plasma species are considered in the theoretical simulation model. The finite element method is used to solve the simulation model for H2O gas release, and the expansion and ionospheric disturbance process at the early stage of high-pressure gas release are studied. It is shown that the space expansion of the released gas is mainly dominated by the pressure difference between the H2O gas and the ionospheric plasma at the early stage of release. Then the diffusion process becomes the dominant process of the space transport of H2O molecules. An electron depletion region forms near the center of the release region due to the chemical reaction and collision process with H2O molecules. Meanwhile, an electron density enhancement region forms on both sides along the magnetic field direction due to the electron snowplow effect. With the increase in the released mass of H2O gas, the intensity and duration of the electron density enhancement increase gradually. With the release position rising, it is found that the intensity of the electron density enhancement has a peak near 380 km and the duration increases slightly with the increasing release height.