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

火山爆发对空中交通、基础设施、人类健康和全球气候都有重大影响。由于危险的条件、喷发时间的不确定性和偏远的喷发地点，这些事件是监测的一个挑战。减轻灾害需要(1)远程探测喷发条件和(2)了解火山上方的火山灰分布，然后这些火山灰可以分散到高层大气中。这项研究将通过探索湍流、火山灰颗粒动力学和带电之间的联系来解决这两个关键问题。火山喷发后，火山灰颗粒会遇到湍流，这会促进颗粒相互作用、带电和聚集。带电的羽流可以触发火山闪电，这是一种壮观的现象，可以用来近乎实时地研究危险的喷发。这些放电产生宽带辐射(例如无线电波)，可以携带有关火山内部的信息，远远超出火山附近的范围。电动力也可以使聚集的粒子结合，加速它们落回地面。此外，羽流和大气中的水分对颗粒聚集有很大的影响。这些过程对火山灰的危害至关重要，但它们的建模具有挑战性。湍流、聚集和带电的影响是密切相关的，但它们的相互作用从未被实验量化过。因此，有必要改进对这些影响的测量，以用于建立准确的火山灰输送模型。该项目将通过参加这些实验和通过科学交流培训来加强对三名研究生的教育，通过这些培训，他们将为公众宣传提供实践示范。该项目旨在通过高精度的实验和先进的计算模型来改进对火山羽流行为的预测。研究小组将对充满颗粒的湍流射流进行实验测量，检查聚集和电场。高分辨率光学技术将研究颗粒混合物中的湍流和聚集，无论有没有水分。电子传感器将测量粒子的电荷，并将测量结果与喷发条件的模型联系起来。结果将被整合到一个计算模型中，该模型可用于远程检查火山羽流条件。此外，这项研究还将通过俄勒冈州科学与工业博物馆(OMSI)和史密森学会的一系列实践演示向公众展示。该项目得到了地球物理学以及岩石学和地球化学计划的支持。该项目由地球物理计划、岩石学和地球化学计划以及地球科学部共同资助，以支持各种机构类型提高研究能力、能力和基础设施的项目，如地球观测组织拥抱DCL所述。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.