CEDAR: Auroral Electrojet Waves and Wave Heating

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One of the important effects of auroral precipitation at high latitudes is the production of waves and turbulence in the ionosphere. These dynamic variations can cause disruption and degradation of communication and navigation signals that pass through the ionosphere. Although ionospheric irregularities were discovered in the auroral zone more than 75 years ago, fundamental questions about the way that the waves propagate and saturate in a turbulent state persist. The purpose of this award is to investigate a particular kind of turbulence referred to as Farley-Buneman waves. The objective is to study the internal mechanics of these waves, their effects on the background ionospheric state, and the interpretation of coherent radar backscatter that can be received from them. The investigation has experimental, theoretical, and modeling aspects as well as strong educational underpinnings. The broad goal of the research is to elucidate the processes involved in generating ionospheric structure by magnetospheric forcing (from above), one of the two main themes highlighted by the 2013 Decadal Survey for Solar and Space Physics. Its emphasis on the multiscale connections between the background forcing available during disturbed conditions, the auroral instability and turbulence it creates, and the feedback on the mean ionospheric state constitutes a systems approach to this complex and highly coupled process. The proposed study will be carried out by faculty and students at Cornell University and the University of Alaska, Anchorage, and will involve experimental field work in Alaska. Experimental data will be interpreted in the context of results from the theoretical investigation. One component of that investigation involves the construction of a 3D hybrid fluid-kinetic model of Farley- Buneman waves capable of simulating the wave mechanics at small and intermediate scales. The second component involves the development of a mathematical model of Farley-Buneman waves and turbulence, including saturation effects, based on the formalism of stochastic differential equations (SDEs). The broader impact of this investigation is associated with the novelty of the tools that will be developed, which have applications outside research in the radar aurora. Radar imaging has tremendous potential as a means of performing discovery research in geospace but is computationally demanding and will see little application outside the current effort until it can be simplified and accelerated. Additional broader impact will come from undergraduate and graduate education in geospace and CEDAR science at Cornell and the University of Alaska.