Quantification of Impact‐Induced Melt Production in Numerical Modeling Revisited
Quantification of Impact‐Induced Melt Production in Numerical Modeling Revisited
复制标题
重新审视数值模拟中冲击引起的熔体生产的量化
DOI：
10.1029/2022je007426
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
Kurosawa Kosuke
中科院分区：
文献类型：
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作者：
Manske Lukas;Wunnemann Kai;Kurosawa Kosuke
撞击陨石坑中岩石的熔化和汽化主要归因于冲击压缩的结果。然而，其他机制，如塑性功和构造隆起的减压也有助于熔体的产生。在这项研究中，我们扩展了在数值模型中由峰值冲击压力确定冲击诱导熔化的常用方法，通过一种新的方法来解释由于塑性功和内耗而产生的额外加热。我们比较了我们的新方法和直接的方法，它简单地根据陨石坑形成过程中任意时间点的温度相对于固相线温度来量化熔化。这种简单得多的方法确实考虑了塑性功，但由于撞击坑形成模型中持续平流所固有的数值扩散，精度降低。我们证明，我们的新方法比以前的方法更准确，特别是在定量确定撞击熔体在最终陨石坑结构中的分布时。此外，我们评估了塑性功对整体熔体体积的贡献，发现熔化是由塑性功主导的，在岩石中以小于7.5-12.5公里/S的速度撞击，这取决于材料的强度。在较高的冲击速度下，冲击压缩是熔化的主要机制。这里，与我们的新模型相比，传统的峰值冲击压力方法提供了类似的结果。我们的方法是一个强大的工具，可以准确地确定碰撞诱导的加热，特别是在相对低速的碰撞中。
Melting and vaporization of rocks in impact cratering is mostly attributed to be a consequence of shock compression. However, other mechanism such as plastic work and decompression by structural uplift also contribute to melt production. In this study we expand the commonly used method to determine shock‐induced melting in numerical models from the peak shock pressure by a new approach to account for additional heating due plastic work and internal friction. We compare our new approach with the straight‐forward method to simply quantify melting from the temperature relative to the solidus temperature at any arbitrary point in time in the course of crater formation. This much simpler method does account for plastic work but suffers from reduced accuracy due to numerical diffusion inherent to ongoing advection in impact crater formation models. We demonstrate that our new approach is more accurate than previous methods in particular for quantitative determination of impact melt distribution in final crater structures. In addition, we assess the contribution of plastic work to the overall melt volume and find, that melting is dominated by plastic work for impacts at velocities smaller than 7.5–12.5 km/s in rocks, depending on the material strength. At higher impact velocities shock compression is the dominating mechanism for melting. Here, the conventional peak shock pressure method provides similar results compared with our new model. Our method serves as a powerful tool to accurately determine impact‐induced heating in particular at relatively low‐velocity impacts.