标题： 热导率对地球核心顶部稳定区域的同时形成及四十余亿年磁场生成的影响 显示英文标题

标题： Effect of thermal conductivity on the simultaneous formation of a stable region at the top of Earth's core and magnetic field generation over four billion years

摘要： 评估了地球外核上部出现分层区域并长期生成磁场的可能性，考虑了地球内核热导率和地核-地幔边界（CMB）当前热流的不确定性。 使用一维热化学模型，针对不同热导率和CMB热流值计算了地球外核的径向结构。 结果表明，存在允许稳定分层出现和长期磁场生成的解，尽管分层区域的厚度小于100公里。 为了满足分层区域的出现和长期磁场生成，可能的当前CMB热流值（13-15太瓦）建议在CMB处的热导率为77-121瓦/米/开尔文，这与根据地球核心条件下的电导率测量估算的值非常吻合。 在这种情况下，分层区域的厚度约为50公里，这也与从地磁年代变化估计的分层区域厚度一致。 然而，通过本分析得到的热导率建议值可能更小，当当前CMB热流小于本研究使用的限制时。 显示英文摘要

摘要： The possibility of the emergence of a stratified region in the uppermost part of the Earth's outer core with long-term magnetic field generation is assessed, taking into account uncertainties in the thermal conductivity of the Earth's core and the present-day heat flow across the core-mantle boundary (CMB). The radial structures of the Earth's outer core are calculated for various values of thermal conductivity and CMB heat flow using a one-dimensional thermo-chemical model. The results show that there exist solutions that allow both emergence of stable stratification and long-term magnetic field generation although their thickness of stratified region is thinner than 100 km. In order to satisfy both emergence of stratified region and long-term magnetic field generation, possible value of the present-day CMB heat flow (13-15 TW) suggests a thermal conductivity of 77-121 W/m/K at CMB, which is in good agreement with the values estimated from the electrical conductivity measurements under the Earth' s core condition. The thickness of the stratified region in this case is about 50 km, which is also consistent with the thickness of the stratified region estimated from the geomagnetic secular variation. However, the proposed values of thermal conductivity obtained by this analysis could be smaller when the present-day CMB heat flow becomes smaller than the constraint used in this study.