Polycrystalline ice is known to exhibit macroscopic anisotropy in relative permittivity (ɛ) depending on the crystal orientation fabric (COF). Using a new system designed to measure the tensorial components of ɛ, we investigated the dielectric anisotropy (Δɛ) of a deep ice core sample obtained from Dome Fuji, East Antarctica. This technique permits the continuous nondestructive assessment of the COF in thick ice sections. Measurements of vertical prism sections along the core showed that the Δɛ values in the vertical direction increased with increasing depth, supporting previous findings of c-axis clustering around the vertical direction. Analyses of horizontal disk sections demonstrated that the magnitude of Δɛ in the horizontal plane was 10–15% of that in the vertical plane. In addition, the directions of the principal axes of tensorial ɛ in the horizontal plane corresponded to the long or short axis of the elliptically elongated single-pole maximum COF. The data confirmed that Δɛ in the vertical and horizontal planes adequately indicated the preferred orientations of the c-axes, and that Δɛ can be considered to represent a direct substitute for the normalized COF eigenvalues. This new method could be extremely useful as a means of investigating continuous and depth-dependent variations in COF.

中文翻译：

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介电各向异性作为 Dome Fuji 冰芯中晶体取向织物的指标：方法和初步结果

已知多晶冰在相对介电常数方面表现出宏观各向异性（ε) 取决于晶体取向织物 (COF)。使用一种新的系统来测量的张量分量ε，我们研究了介电各向异性（Δε) 从南极洲东部圆顶富士获得的深冰芯样本。该技术允许对厚冰段中的 COF 进行连续无损评估。沿核心垂直棱镜截面的测量表明，Δε垂直方向的值随着深度的增加而增加，支持先前的发现C-轴围绕垂直方向聚类。对水平盘截面的分析表明，Δε水平面的 10-15% 是垂直面的。此外，张量的主轴方向ε在水平面上对应于椭圆形拉长的单极最大 COF 的长轴或短轴。数据证实Δε在垂直和水平平面上充分表明了 c 轴的优选方向，并且 Δε可以被认为是对归一化 COF 特征值的直接替代。这种新方法作为研究 COF 中连续和深度相关变化的一种手段可能非常有用。