Experimental study of planetary ices at high pressure-high temperature using dynamically-driven diamond-anvil cells

使用动态驱动金刚石砧室进行高压高温行星冰的实验研究

• 批准号: 439663827
• 负责人: Professorin Dr. Carmen Sanchez-Valle, Ph.D.
• 金额: --
• 依托单位: Deutsches Elektronen-Synchrotron (DESY)
• 依托单位国家: 德国
• 项目类别: Research Units
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/439663827?language=en
• 关键词: Experimental; study; planetary; ices; pressure

Planetary ice compounds (e.g. H2O, CH4, NH3) constitute large parts of solar giant ice planets and are likely abundant in the interiors of recently discovered mini-Neptune exoplanets. Yet, their physical properties are poorly understood at relevant conditions (>100 GPa and 2000 K). Previous X-ray diffraction studies in diamond anvil cells (DAC) have been limited by the small scattering efficiency of these low-Z compounds and their reactivity with the diamond anvils. These shortcomings can be avoided by compressing the sample on short time scales (miliseconds to seconds) using dynamically-driven DACs. In subproject SP9, we will take advantage of new capabilities for fast compression studies of ice phases in DACs coupled with time-resolved X-ray diffraction diagnostics implemented at PETRA III and the European XFEL during FOR2440, to investigate the behavior of ices in the H2O-NH3 system. We will specifically determine the stability, structure and equations of state of H2O, NH3 and H2O-NH3 ices up to 150GPa and 5000 K. Initial experiments will be performed at PETRA III employing resistive heated dynamically-driven DACs commissioned during FOR2440. To reach the high temperature conditions of the superionic ice phases (>2000$ K), we will combine conventional laser heating experiments at PETRA III with a novel approach for X-ray heating of the sample with consecutive EuXFEL pulses (in collaboration with SP7). The experimental results will provide new anchor points to constrain computational predictions (in collaboration with SP3) and serve as input parameters for large-scale numerical models to constrain the internal structure and dynamics of exoplanets (in collaboration with SP5).

行星冰化合物（例如H2O、CH4、NH3）构成了太阳巨冰行星的大部分，并且在最近发现的迷你海王星系外行星的内部可能含量丰富。然而，人们对它们在相关条件（>100 GPa 和 2000 K）下的物理特性知之甚少。先前在金刚石砧座 (DAC) 中进行的 X 射线衍射研究受到这些低 Z 化合物的小散射效率及其与金刚石砧的反应性的限制。通过使用动态驱动的 DAC 在短时间尺度（毫秒到秒）内压缩样本，可以避免这些缺点。在子项目 SP9 中，我们将利用 DAC 中冰相快速压缩研究的新功能，以及 FOR2440 期间在 PETRA III 和欧洲 XFEL 上实施的时间分辨 X 射线衍射诊断，来研究 H2O-NH3 系统中冰的行为。我们将专门确定高达 150GPa 和 5000 K 的 H2O、NH3 和 H2O-NH3 冰的稳定性、结构和状态方程。初步实验将在 PETRA III 进行，采用 FOR2440 期间调试的电阻加热动态驱动 DAC。为了达到超离子冰相的高温条件（>2000$ K），我们将 PETRA III 的传统激光加热实验与使用连续 EuXFEL 脉冲对样品进行 X 射线加热的新方法相结合（与 SP7 合作）。实验结果将提供新的锚点来约束计算预测（与SP3合作），并作为大规模数值模型的输入参数来约束系外行星的内部结构和动力学（与SP5合作）。