Comparison of the linear Rayleigh-Taylor instability and equatorial plasma bubbles using WAM-IPE and ROCSAT-1

The prediction of the equatorial plasma bubble (EPB) has been one of the most important issues in space weather forecasting. The Rayleigh-Taylor (R-T) instability mechanism is fundamentally linked to the generation of EPBs in the ionosphere. Previous studies have showed that the global morphology of the evening prereversal enhancement (PRE) of vertical ion drift have a good agreement with the global morphology of EPB occurrence probability. The growth rate of R-T instability is primarily influenced by the ambient zonal electric field, which correlates with vertical drift, thus enabling the potential linkage between R-T instability and EPB occurrence probability. This study aims to explore the predictability of EPB occurrence by correlating the R-T instability growth rate with EPB occurrence probabilities. We utilize the coupled Whole Atmosphere Model and Ionosphere Plasmasphere Electrodynamic (WAM-IPE) model, incorporating a new integrated R-T instability growth rate formulation based on the Quasi-Dipole Coordinates and the modified electrodynamics equations. The variations and the distributions of EPB occurrence probability are observed by ROCSAT-1 during 1999–2004. A comprehensive analysis comparing these two aspects is presented. Additionally, the instantaneous amplitude and frequency determined by the Hilbert-Huang transform are also employed to reveal the scale size of the EPB and serve as a reference parameter.