This collaborative award is for a study of the complex spatial structure exhibited by ionosphere plasma in Earth's polar regions. Small-scale plasma structuring modifies the phase and amplitude of trans-ionospheric radio signals, producing significant scintillation activity. These effects are detrimental to communication and navigation systems but can be used as a remote-sensing diagnostic to help discern the characteristics of fundamental small-scale plasma processes that result in ionospheric structure. This research will improve understanding of the two major processes contributing to ionospheric scintillation: gradient drift and Kelvin Helmholz instabilities. The research plan directly relate to goals of NSF Aeronomy and CEDAR programs to investigate cross-scale coupling in the ionosphere-thermosphere-magnetosphere system, and would be applicable to other disciplines within plasma physics. The team will develop and apply rarely utilized capabilities of the Resolute Bay incoherent scatter radar (RISR), expanding the range of measurements the community can easily request from this facility while also advancing modeling capabilities. The project is co-led by two early-career scientists including a first-time NSF PI. The award enhances the space physics program at ERAU with support provided for one undergraduate student and one graduate student.
Spatial irregularities within ionospheric plasma undergo dynamical evolution under the influence of magnetospheric forcing and internal ionospheric processes, producing a cascade of energy moving generally from large scales into intermediate and small scale structures. These scales are believed to be generated by a variety of instability mechanisms and structuring processes, but the details of the evolution of this plasma structuring over time are poorly constrained, especially for the non-linear aspects. The research plan will focus upon detailed data-model synthesis to characterize physical parameters expected to contribute to irregularity evolution in the ionosphere (i.e., large-scale density structures, background velocity fields, gradients and shears, and precipitation regions). The approach include modeling of radio wave propagation (using SIGMA) and polar cap ionosphere based upon the ingestion of existing and new observations from RISR, characterizing large-to-medium scales and scintillation activity using GPS (L-band) and UHF/VHF radio beacons. Results will be interpreted through comparisons with the predictions of a physics-based instability model as represented by the GEMINI model to characterize observable effects of ionospheric instability in many idealized situations and for select case studies based on data-driven model inputs.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
