メルト輸送過程を考慮した地球内核成長モデルによる地震波異方性の成因解明

该项目的目标是确定熔体被困在深处并且系统不稳定和不稳定应该发展的参数范围，并描述和量化由这种流动引起的变形。我开发了一个基于两相流动动力学的半解析模型，以研究内芯在生长过程中的紧实度。在Sumita等人先前的研究之后。(1986)，我模拟了一个自引力球体的压缩过程，而球体是从顶部的结晶生长而来的。该系统允许两个主要参数的变化：增长速度和压缩长度。为了探索地球内核可能的动力学，我研究了三种不同的增长设置：恒定增长速度，来自Labrosse等人的实际增长。2014年和Huguet等人2018年的过冷核。由于地球内核的压缩长度被认为小于100公里，因此最有希望将熔体捕获到系统中的方案是过冷的内核，将高达30%的熔体困在内核深处。这个融化量太大了，无法观测到今天内核中的剪切波，这有助于我们限制过冷的合理上限。

The goal of the project was to determine the range of parameters for which melt is trapped in depth and the system is unstable and instabilities should develop, and to describe and quantify the deformation induced by such flows.I developed a semi-analytical model, based on two-phase flow dynamics to study the compaction of the inner core as it is growing. Following previous study of Sumita et al. (1986), I modeled the compaction of a self-gravitating sphere, while the sphere is growing from crystallization at the top. The system allow for variations of two main parameters: growth rate and compaction length.To explore the possible dynamics for the Earth’s inner core, I studied three different set-up for the growth: constant growth rate, realistic growth from Labrosse et al. 2014 and supercooled core from Huguet et al 2018. As the compaction length for the inner core of the Earth is thought to be smaller than 100km, the most promising scenario to trap melt in the system is the supercooled core, trapping up to 30% of melt in the depth of the core. This amount of melt is too large for the observations of shear waves in today’s inner core, which help us constraining reasonnable upper bound for supercooling.