Equatorial Plasma Bubbles Generated by the Whole Atmosphere Model

One of the key issues concerning the formation of equatorial plasma bubbles and the radio scintillation that they cause is the mechanism and structure of the phenomena that trigger them. Usually, simulations of the generation of plasma bubbles rely on some arbitrary initial perturbation that develops into the bubble as a consequence of the Rayleigh-Taylor and other plasma instabilities. For this study (done with the 3-d plasma bubble model of Retterer), we instead begin with no initial plasma perturbation, but rely on the structured winds and dynamo electric fields of the Whole Atmosphere Model (WAM) to naturally generate the plasma perturbations that develop into bubbles when the plasma becomes unstable. (WAM is a 150-layer general circulation model based on the US National Weather Service's operational Global Forecast System (GFS) model extended upward to cover the atmosphere from the ground to about 600 km. It was developed as part of the Integrated Dynamics through Earth's Atmosphere (IDEA) project to study the generation, vertical propagation, possible nonlinear interactions, and effects of planetary waves and tides originating in the lower atmosphere, as part of an effort to understand the variability of the upper atmosphere and ionosphere.) We will show that such forcing can generate the initial perturbations needed for the development of the Rayleigh-Taylor instability, and discuss the potential for this kind of forcing to explain the day-to-day variability of the phenomena of the plumes and scintillation.