In this paper, we present a new experimental facility, Little Earth Experiment, designed to study the hydrodynamics of liquid planetary cores. The main novelty of this apparatus is that a transparent electrically conducting electrolyte is subject to extremely high magnetic fields (up to 10 T) to produce electromagnetic effects comparable to those produced by moderate magnetic fields in planetary cores. This technique makes it possible to visualise for the first time the coupling between the principal forces in a convection-driven dynamo by means of Particle Image Velocimetry (PIV) in a geometry relevant to planets. We first present the technology that enables us to generate these forces and implement PIV in a high magnetic field environment. We then show that the magnetic field drastically changes the structure of convective plumes in a configuration relevant to the tangent cylinder region of the Earth's core.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1063/1.4960124 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Effect of Reservoir Heterogeneity on Polymer-Surfactant Binary Chemical Flooding Efficiency in Conglomerate Reservoirs.
Polymers (Basel)
December 2024
College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
Reservoir heterogeneity significantly affects reservoir flooding efficiency and the formation and distribution of residual oil. As an effective method for enhancing recovery, polymer-surfactant (SP) flooding has a complex mechanism of action in inhomogeneous reservoirs. In this study, the effect of reservoir heterogeneity on the SP drive was investigated by designing core parallel flooding experiments combined with NMR and CT scanning techniques, taking conglomerate reservoirs in a Xinjiang oilfield as the research object.
View Article and Find Full Text PDFControl of hydrogen concentrations by microbial sulfate reduction in two contrasting anoxic coastal sediments.
Front Microbiol
November 2024
Department of Microbiology, The University of Tennessee, Knoxville, Knoxville, TN, United States.
Introduction: Molecular hydrogen is produced by the fermentation of organic matter and consumed by organisms including hydrogenotrophic methanogens and sulfate reducers in anoxic marine sediment. The thermodynamic feasibility of these metabolisms depends strongly on organic matter reactivity and hydrogen concentrations; low organic matter reactivity and high hydrogen concentrations can inhibit fermentation so when organic matter is poor, fermenters might form syntrophies with methanogens and/or sulfate reducers who alleviate thermodynamic stress by keeping hydrogen concentrations low and tightly controlled. However, it is unclear how these metabolisms effect porewater hydrogen concentrations in natural marine sediments of different organic matter reactivities.
View Article and Find Full Text PDFMagnetic Taylor-Proudman Constraint Explains Flows into the Tangent Cylinder.
Phys Rev Lett
November 2024
Laboratoire National des Champs Magnétiques Intenses (LNCMI), CNRS UPR 3228, EMFL, Université Toulouse III-Paul Sabatier, Université Fédérale Toulouse Midi-Pyrénées, Institut National des Sciences Appliquées, Université Grenoble Alpes, 38042 Grenoble CEDEX, France.
Tangent cylinders (TCs) have shaped our understanding of planetary dynamos and liquid cores. The Taylor-Proudman constraint creates these imaginary surfaces because of planetary rotation, separating polar and equatorial regions, but cannot explain the flows meandering through them. Here, we establish and verify experimentally that magnetic fields aligned with rotation drive flows into TCs, linked to the flows along TCs by a magnetic Taylor-Proudman constraint.
View Article and Find Full Text PDFLong-term persistency of a strong non-dipole field in the South Atlantic.
Nat Commun
November 2024
Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, São Paulo, SP, Brazil.
Earth's magnetic field exhibits a dominant dipole morphology. Notwithstanding, significant deviations from the dipole are evident today, particularly the South Atlantic Anomaly (SAA), characterized by anomalously low-field intensity and high directional variability, diminishing the field's shielding effect. To assess the persistence of SAA-like features over multimillion-year scales, we combine paleomagnetic data from Trindade Island (20°30'S, 29°22'W) with an evaluation of paleosecular variation (PSV) over the past 10 Myr.
View Article and Find Full Text PDFThe Greenland spatial fingerprint of Dansgaard-Oeschger events in observations and models.
Proc Natl Acad Sci U S A
October 2024
Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80303.
Article Synopsis
- The study examines abrupt climate changes during the Pleistocene Ice Ages, known as Dansgaard-Oeschger (DO) oscillations, using Greenland ice cores to analyze temperature shifts and their potential long-term impacts.
- It introduces new ice-core records from southern and eastern Greenland to enhance understanding of DO event magnitudes and creates a multiproxy assessment of their effects across Greenland.
- The findings suggest that variations in wintertime sea ice in the North Atlantic subpolar gyre are crucial for explaining DO variability, and that changes in vapor source distribution, rather than site temperature, mainly influence Greenland's isotope signals during these climate transitions.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!