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1. Katabatic Wind-Driven Exchange in Fjords: WIND-DRIVEN EXCHANGE

   https://doi.org/10.1002/2017JC013026  

   Spall, Michael A. ; Jackson, Rebecca H. ; Straneo, Fiammetta ( October 2017 , Journal of Geophysical Research: Oceans)
2. Fusing Model-Driven and Data-Driven Approaches for GMD Mitigation

   Murphy, S ; Schuman, J ; Schultz, A ( March 2017 , CIGRE US National Committee 2017 Grid of the Future Symposium)

   The operation of the electric power grid is foundational to the health, safety, and economic well-being of the nation, yet it is increasingly fragile and exposed to risk from exogenous factors. When power disruptions are widespread, prolonged, or impact critical services, the consequences can be grave. GMDs) can impact electric power transmission grids through premature ageing and transformer failure, which can lead to cascading failures and extended power disruptions. Geomagnetically induced currents (GICs) arising from geomagnetic disturbances (GMD mitigation poses a challenging problem to grid operators due to the nature of its impact. Space weather events arising from solar coronal mass ejections (CMEs) that intersect Earth's orbit occur on a continuum of timescales and levels of severity. Moderately sized CMEs, such as the 1989 event that lead to the failure of the HydroQuebec system, illustrate the risk to the power grid. Even larger space weather events that have the potential for profound impacts and prolonged power disruptions on a continental scale are thought to happen approximately storm has occurred during the existence of electric infrastructure. At the other end of the severity spectrum, recent evidence has shown that GICs flow at low levels continuously on the grid even in the every one hundred years; however, no such absence of a solar storm. This behavior may cause eventual, but slow to manifest breakdown of grid assets misattributed to non-GMD causes. In either case, it is difficult for utilities to justify the costly installation of sensors and telemetry to monitor this phenomenon. This paper details a system to augment human operators with two new abilities—(1) the real-time prediction of GICs flowing on their system and (2) the real-time monitoring of GMD grid manifestations—without installing new sensors. The system will do this by fusing a “top-down” approach using physics-based modeling driven by detailed 3-D Earth conductivity measurements and real-time magnetic observatory data with a “bottom-up” approach using artificial intelligence techniques driven by synchrophasor data. This hybrid methodology will enable utility operators to identify the best strategies to modify grid voltages and topology to mitigate damage and deal with a changing federal regulatory framework that requires GMD monitoring and mitigation efforts. 

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3. Foam-driven fracture

   https://doi.org/10.1073/pnas.1808068115  

   Lai, Ching-Yao ; Rallabandi, Bhargav ; Perazzo, Antonio ; Zheng, Zhong ; Smiddy, Samuel E. ; Stone, Howard A. ( July 2018 , Proceedings of the National Academy of Sciences)
4. Cooling-driven coagulation

   https://doi.org/10.1093/mnras/stad1874  

   Gronke, Max ; Oh, S_Peng ( June 2023 , Monthly Notices of the Royal Astronomical Society)

   Astrophysical gases such as the interstellar-, circumgalactic-, or intracluster-medium are commonly multiphase, which poses the question of the structure of these systems. While there are many known processes leading to fragmentation of cold gas embedded in a (turbulent) hot medium, in this work, we focus on the reverse process: coagulation. This is often seen in wind-tunnel and shearing layer simulations, where cold gas fragments spontaneously coalesce. Using 2D and 3D hydrodynamical simulations, we find that sufficiently large (≫cstcool), perturbed cold gas clouds develop pulsations which ensure cold gas mass growth over an extended period of time (≫r/cs). This mass growth efficiently accelerates hot gas which in turn can entrain cold droplets, leading to coagulation. The attractive inverse square force between cold gas droplets has interesting parallels with gravity; the ‘monopole’ is surface area rather than mass. We develop a simple analytic model which reproduces our numerical findings.

    

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5. Superposed Epoch Analyses of Electron‐Driven and Proton‐Driven Magnetic Dips

   https://doi.org/10.1029/2021GL094934  

   Zhu, Hui ; Chen, Lunjin ; Artemyev, Anton V. ; Zhang, Xiao‐Jia ; Breneman, A. W. ( November 2021 , Geophysical Research Letters)

   In this study, we statistically investigate the features of magnetic dips by constructing superposed epoch analysis on Van Allen Probe data. Based on the values of electron and proton plasma betas, we categorize dips into two types: electron‐dominant and proton‐dominant. The global distributions of dips are obtained. Superposed epoch analysis on two types reveals a correlation between the magnetic fluctuations and plasma betas. Moreover, the occurrences of butterfly pitch angle distributions of relativistic electrons driven by the magnetic dips are confirmed on a statistical basis. Our results reveal the statistical characteristics of magnetic dips and establish the relationship among the magnetic fluctuations and background plasma parameters, indicating the potentially important role of magnetic dips in the inner magnetosphere dynamics.

    

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