Experimental Studies of Convection in the Earth's Core

地核对流的实验研究

• 批准号: 0229791
• 负责人: Jonathan Aurnou
• 金额: $ 39.01万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-01-01 至 2006-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0229791&HistoricalAwards=false
• 关键词: Experimental; Studies; Convection; Earth; Core

AurnouEAR-0229791This proposal requests funding for work in a new experimental fluidmechanics laboratory at UCLA. The lab will utilize two, new powerfuldiagnostic techniques to provide high-resolution, quantitative velocitymeasurements of simulated convection in the Earth's outer core. Theresults will test long-held theories regarding the properties ofconvective flows in core fluids and will provide a detailedcharacterization of flow dynamics at nearly planetary parameter values.The first project will use the recently developed technique of acousticDoppler velocimetry to study convecting liquid metals, which havephysical properties similar to that of the molten outer core. Theresults will test the linear stability theory of rotatingmagnetoconvection, the foundation of modern dynamo theory. Establishedby Chandrasekhar in the 1950's, this stability theory has only undergonea single prior experimental investigation that reached the asymptoticregime. The second project will utilize the optical technique ofparticle image velocimetry (PIV), applying it to a rotating sphericalshell of convecting water, a set-up that mimics the dynamics and thegeometry of the outer core. PIV will provide, for the first time,quantitative measurements of the flow fields (velocity, vorticity andhelicity) that are believed to be essential components of the geodynamo,but have never been measured adequately by experimental means.Furthermore, the experimental design will enable PIV to measureconvection in the polar regions, which have not been studied extensivelybut now appear to be significant. Together, these state-of-the-artacoustic and optical velocimetry techniques will provide benchmarks fornumerical and theoretical studies of core convection and the geodynamo.They will also generate the highest resolution experimental convectiondata to date for interpreting geomagnetic and seismic observations ofthe deep Earth.

Aurnouear-0229791该提案要求在UCLA的新实验流体力学实验室中进行资金。该实验室将利用两种新型强大的诊断技术来提供地球外部芯中模拟对流的高分辨率，定量速度测量。 Thereults将测试有关核心流体中概念流的特性的长期持有的理论，并将在几乎行星参数值下提供流动动力学的详细术语。第一个项目将使用最近开发的Acousticdoppler Velocimetry技术来研究对流的液体金属，从而使对对流的特性类似于糖浆的外粒子。 Theresults将测试现代发电机理论的基础旋转旋转对照的线性稳定性理论。该稳定理论在1950年代建立了Chandrasekhar，只有在达到渐近领域的实验研究中，只有单一的实验研究。第二个项目将利用粒子图像速度法（PIV）的光学技术，将其应用于对流水的旋转球形，该设置模拟了外部核心的动力学和地域。 PIV将首次提供流动场（速度，涡度和瑟度）的定量测​​量，这些测量被认为是地球诺（Geodynamo）的必不可少的组成部分，但从未通过实验手段进行充分的测量。Furthermore将在隔离区域中启用PIV的piv evertiment op extections exterivate extections everative everatife of the extructiate of the evertival of deart的范围。共同，这些最先进的和光学的速度测定技术将为核心对流和地球诺（Geodynamo）提供基准和理论研究。它们还将产生迄今为止解释深层地球的地球磁和地震观察的最高分辨率实验对流。