Geophysics of Iron in the Earth's Core

对穿过我们星球的地震波的分析提供了对其内部结构的观察，包括地球的核心，它由位于固体、富铁的核心上方的富含液态铁的外层区域组成。为了了解组成这个地球上最偏远地区的成分，我们提议在地球-S深部存在的高压和温度下进行具有挑战性的实验室实验，并测量在极端条件下可以显著改变的富铁材料的性质。因此，目前研究的主要目标是了解在地球的演化、磁性、动态过程和热演化中发挥核心作用的地核。在我们先前支持所取得的进展的基础上，该项目采取了双管齐下的方法：使用钻石顶压室中的静态高压技术来准确确定弹性特性和由用于超高压-温度声速测量的强大激光产生的动态压缩。对于静态高压实验，我们建议使用一套互补的同步辐射X射线技术来确定铁的状态方程、聚集的纵波和横波速度、速度各向异性和晶格择优取向以及弹性张量。对于动态实验，我们将与劳伦斯利弗莫尔国家实验室的冲击物理组合作，使用Janus激光设备来确定铁和铁合金的纵波速度，特别是横波速度(使用横向位移干涉仪设置)。静态和动态结果的结合将为帮助理解和解释地核复杂的地震特征提供重要信息。预期的铁的高压-温度弹性数据将对参与地球深部研究的各种研究人员(例如，用于改进其计算的理论矿物物理学家、用于解释其观测结果的地震学家以及用于约束其模型的地球动力学家)具有价值。此外，这些技术进步将对地球科学以及基础和应用科学的其他实验者有用。

Analyzing the seismic waves that pass through our planet have provide observations of its internal structure including, the Earth's core which is composed of a liquid iron-rich outer region which lies above the solid, iron-rich inner core. In order to understand the constituents that make up this most remote region in our planet, we propose to conduct the challenging laboratory experiments at the high pressures and temperatures that exist in the Earth?s deep interior, and to measure of the properties of iron-rich materials which can be dramatically altered under the extreme conditions. The primary goal of the present research is thus to understand the Earth's core which plays a central role in the evolution, magnetism, dynamic processes, and thermal evolution of our planet. Building upon our progress resulting from our prior support, this project takes a two-pronged approach: using static high-pressure techniques in a diamond anvil cell for accurate determination of elastic properties and dynamic compression created by powerful lasers for ultrahigh pressure-temperature sound velocity measurements. For the static high-pressure experiments, we propose to determine the equation of state, aggregate compressional and shear wave velocities, velocity anisotropy and lattice preferred orientation, and elastic tensor of iron using a suite of complementary synchrotron x-ray techniques. For the dynamic experiments, we will collaborate with the Shock Physics Group at Lawrence Livermore National Laboratory and use the Janus laser facility to determine the compressional and especially the shear wave velocities (using a transverse displacement interferometer set-up) for iron and iron alloys. The combination of the static and dynamic results will provide important information for helping to understand and interpret the complex seismic signatures in the Earth's core. The anticipated, high pressure-temperature elasticity data for iron will be valuable to a wide variety of researchers involved in deep Earth studies (e.g. theoretical mineral physicists for improving their calculations, seismologists for interpretation of their observations, and geodynamicists for constraining their models). In addition, the technical advances will be useful to other experimentalists in the geosciences as well as fundamental and applied sciences.