CAREER: Elasticity and Lattice Dynamics of Iron Alloys under Earth's Core Conditions

地核位于地球的中心，是地球最内部但极具活力的区域。在过去的二十年里，地球物理学家花费了巨大的努力来破译地核的成分组成、热结构和地震特征。了解地核的性质和动力学可以深刻地提高我们理解磁场产生过程、地球深部的热化学演化以及地球作为宜居行星的形成的能力。该学院早期职业发展(CALEAR)项目旨在利用多尺度最先进的实验设备，研究铁合金作为内芯候选材料在高温高压条件下的弹性和晶格动力学。拟议研究的结果是一组关于铁合金在以前未知的压力-温度制度下的密度、声速和单晶弹性的新的基本矿物物理数据，对于我们提供对核心的成分和动力学的进一步限制是必不可少的。实验结果将被整合到一个以矿物物理为核心的综合数据库中，促进与地震学、地球动力学和地球化学等姊妹学科的合作，最终加强我们对地球最深处的自然和动力学的深刻理解。此外，学生研究人员参与拟议的研究，并开发高压矿物和材料科学的研究和教学设施，将启动帮助影响和吸引不同的学生群体，特别是传统上未被充分代表的少数民族进入地球科学并建立不同的地球科学工作队伍的“管道”。这项提议旨在系统地测量用于内核的候选铁合金的高压-温度弹性和振动性能，使用基于同步加速器的X射线光谱仪结合电阻加热和激光加热的钻石砧座技术，以解决以下科学问题：(1)压力和温度如何影响核心条件下铁合金的弹性和振动性能？(2)候选轻元素对核心条件下铁的弹性有何合金化作用？(3)接近核心条件的铁合金的单晶弹性是什么，用于解释内核的地震各向异性和精细地震？(4)最后，内核中可能较轻的合金成分是什么，这对内核和地球的热化学演化意味着什么？综合教育和外联的目标是在实验室和同步加速器的设施中培训新一代独立的固体地球地球科学家，并通过在地球科学课程中实施“多锤新闻实验室”(MAPLab)教学模块，向16岁至16岁的学生提供探究式学习机会和经验。该项目的成果将通过国家和国际会议、公开讲座和外联以及新闻媒体及时广泛传播。

Residing at the center of the Earth, the core is the innermost but extremely dynamic region of our planet. Over the last two decades, geophysicists have expended tremendous effort in deciphering the compositional makeup, thermal structure, and seismic features of the Earth's core. Understanding the nature and dynamics of the core can deeply enhance our abilities in understanding the magnetic field generation process, the thermo-chemical evolution of the Earth's deep interior, and the formation of the Earth as a habitable planet. This Faculty Early Career Development (CAREER) program aims to investigate the elasticity and lattice dynamics of iron alloys as candidates for the inner core under high pressure and temperature conditions of the core, using multiscale state-of-the-art experimental facilities. The outcome of the proposed research is a new set of fundamental mineral physics data on density, sound velocities, and single-crystal elasticity of iron alloys under previously uncharted pressure-temperature regimes, essential for us to provide further constraints on the core's composition and dynamics. The experimental results are to be integrated to a comprehensive mineral physics database for the core, cultivating collaborations with sister disciplines such as seismology, geodynamics and geochemistry, and ultimately enhancing our profound understanding of nature and dynamics of the Earth's deepest interior. Furthermore, the involvement of student researchers in the proposed research and the development of a research and teaching facility for high-pressure mineral and materials science will initiate the 'pipeline' that helps influence and attract diverse student population, particularly traditionally underrepresented minorities, into Earth science and build diverse geoscience workforce.This proposal aims to systematically measure high pressure-temperature elastic and vibrational properties of candidate iron alloys for the inner core, using synchrotron-based X-ray spectroscopies combined with resistively- and laser-heated diamond anvil cell techniques, so as to address the following scientific questions: (1) How do pressure and temperature affect the elastic and vibrational properties of iron alloys under core conditions? (2) What are the alloying effects of candidate light elements on the elasticity of iron under core conditions? (3) What are the single crystal elasticities of iron alloys approaching the core conditions, for the interpretation of the inner core's seismic anisotropy and fine-scale seismic? (4) Finally, what are the likely lighter alloying components in the inner core and what would that imply for the thermochemical evolution of the core and the planet? The integrated education and outreach objective is to train a new generation of independent solid Earth geoscientists in laboratory- and synchrotron-based facilities and to offer inquiry-base learning opportunities and experience to K-16 students through the implementation of a 'Multi-Anvil Press Laboratory' (MAPLab) teaching module to geosciences curricula. The results of the project will be widely disseminated on a timely manner through national and international meetings, public lectures and outreach, and news media.