Thermal and Electrical Conductivity of Iron at Planetary Core Conditions from Ab Initio Computations

从头计算得出行星核心条件下铁的导热性和导电性

• 批准号: 169824178
• 负责人: Dr. Gerd Steinle-Neumann, since 1/2012
• 金额: --
• 依托单位: Bayerisches Forschungsinstitut für Experimentelle Geochemie und Geophysik (BGI)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/169824178?language=en
• 关键词: Thermal; Electrical; Conductivity; Iron; Planetary

The thermal and electrical conductivities of iron at high pressure and temperature are key constraints in determining the character of magnetic field generation in, and thermal history of, terrestrial planetary cores. Yet, as a result of tremendous technical challenges associated with the measurement of these properties at high pressure, their values remain very uncertain, varying by about a factor of three. As an example, this difference is sufficient to result in notably different thermal histories for the Earth s core, which crucially determines the development and generation of its magnetic field. We will accurately and reliably compute the thermal and electrical conductivity of the fcc, bcc, hcp, and liquid iron, over the range of pressures and temperatures relevant to terrestrial cores (0-400 GPa; 1000-7000 K). To do this we will use state of the art electronic structure methods in the framework of density-functional theory (DFT), to independently obtain the lattice thermal conductivity, electronic thermal conductivity and electrical conductivity. This will also enable us to self-consistently test, at high pressure and temperature, the theoretical approximations upon which current estimates of electrical and thermal conductivity at very high pressures are based.

铁在高压和高温下的热导率和电导率是决定类地行星核的磁场产生特性和热历史的关键制约因素。然而，由于与高压下测量这些特性相关的巨大技术挑战，它们的值仍然非常不确定，相差约三倍。例如，这种差异足以导致S地核的热历史显著不同，这对其磁场的发展和产生起着至关重要的作用。我们将准确可靠地计算FCC、BCC、HCP和铁液在与地核相关的压力和温度范围内(0-400 GPA；1000-7000K)的热导率和电导率。为此，我们将在密度泛函理论(DFT)的框架下使用最新的电子结构方法，独立地获得晶格热导率、电子热导率和电导率。这也将使我们能够在高压和高温下自洽地测试理论上的近似值，目前对高压下的电导率和热导率的估计所基于的理论近似值。