Collaborative Research: Aggregation and Electrification in a Laboratory-scale Volcanic Plume

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Explosive volcanic eruptions have significant impacts on air traffic, infrastructure, human health, and global climate. These events are a challenge to monitor due to hazardous conditions, uncertainty in eruption timing, and remote eruption locations. Hazard mitigation requires (1) remote detection of eruption conditions and (2) an understanding of the ash distribution above the volcano, which can then disperse across the upper atmosphere. This study will address both critical issues by exploring the link between turbulence, ash particle dynamics, and electrification. Following an eruption, volcanic ash particles encounter turbulence, which can promote particle interaction, electric charging, and clustering. Electrified plumes can trigger volcanic lightning, a spectacular phenomenon that may be used to study hazardous eruptions in near real-time. These discharges generate broadband radiation (e.g. radio waves) that can carry information about the interior of the flow far beyond the immediate vicinity of the volcano. Electrical forces can also cause clustered particles to combine, accelerating their fall back to the ground. In addition, particle aggregation is strongly influenced by moisture in the plume and the atmosphere. These processes are critical to the hazards of volcanic ash, yet they are challenging to model. The effects of turbulence, aggregation, and electrification are closely linked, but their interactions have never been experimentally quantified. Hence, there is a need for improved measurements of these effects, which can be used to create accurate models of volcanic ash transport. This project will enhance the education of three graduate students through participation in these experiments and through scientific communication training through which they will develop hands-on demonstrations for public outreach. This project aims to develop improved predictions of volcanic plume behavior through high-accuracy experiments and advanced computational models. The research team will conduct experimental measurements of turbulent jets filled with particles, examining both aggregation and electric fields. High-resolution optical techniques will study turbulence and clustering in the particle mixtures, both with and without moisture. Electrical sensors will measure particle charging, and the measurements will be linked to models of the eruption conditions. The results will be integrated into a computational model, which can be used to examine volcanic plume conditions remotely. In addition, the research will be presented to the public through a series of hands-on demonstrations at the Oregon Museum of Science and Industry (OMSI) and the Smithsonian Institution. This project was supported by both the Geophysics and the Petrology and Geochemistry programs. This project is jointly funded by the Geophysics Program, Petrology and Geochemistry Program, and the Division of Earth Sciences to support projects that increase research capabilities, capacity and infrastructure at a wide variety of institution types, as outlined in the GEO EMBRACE DCL.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.