Magnetospheric Ducts and Their Role and Importance in Whistler Mode Wave Propagation and Wave-particle Interactions in the Inner Magnetosphere

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In the geospace environment, large-scale (10-100 km) field-aligned magnetospheric ducts are important to the dynamics and energy transport of the magnetosphere and ionosphere. These regions have irregular density enhancements and depletions that affect the nature of wave-particle interactions. The project studies this process and could lead to improvements of space-based technology, including GPS and satellite communications, and predictive models of space weather. The project supports a graduate student and early career assistant professor.Despite their importance in the physics of the inner magnetosphere, relatively few measurements of magnetic ducts are available because appropriate experimental methods have previously not been developed. Whistler mode (WM) and Z- mode (ZM) sounding from the IMAGE satellite provides a new generation of methods to measure field-aligned electron density and magnetospheric ducts. Using these new methods, the research will investigate magnetospheric ducts and develop a new understanding of the role and importance of ducts in inner magnetospheric processes. The objectives of the project are: (1) to obtain new measurements of duct widths, density enhancements, and occurrence patterns and morphology as a function of geomagnetic and solar activity; (2) to gain new understanding of physical processes that lead to the formation, sustenance, and decay of ducts; and (3) to gain a new understanding of the role of ducts in inner magnetospheric processes. An approach involving data analysis and ray tracing simulations will be used to achieve the objectives described above. The WM and ZM radio sounding and passive measurements from RPI/IMAGE will be the principal source of data used in this research. Results obtained from WM and ZM radio sounding will be augmented and enhanced using complementary wave and particle data available from other ground and space-borne instruments (e.g. ground VLF receivers; satellite wave and particle detectors).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.