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yexuqing木虫之王 (文学泰斗)
太阳系系主任
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[交流]
Shear-induced bubble nucleation in magmas
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岩浆中的剪切诱导气泡成核 ▲ 作者：Olivier Roche, Jean-Michel Andanson et al. ▲链接： https://www.science.org/doi/10.1126/science.adw8543 ▲摘要：岩浆中气泡的成核作用是控制火山喷发动力的关键因素。这项研究中，研究者聚焦于火山环境中普遍存在的、由黏性剪切作用触发的挥发性饱和液体成核过程。 通过结合实验室试验、理论分析和数值模拟，研究者探究了在挥发性过饱和液体中，机械剪切能量促进气体分子核形成与生长的条件。 研究结果表明，成核所需的临界剪切应力随挥发性过饱和度的增加而降低。对自然体系进行的量纲分析显示，剪切诱变成核很可能发生在火山通道中，这一发现对岩浆脱气过程和喷发模式具有重要启示。 ▲ Abstract： The nucleation of gas bubbles in magmas is fundamental to controlling the dynamics of volcanic eruptions. In this study, we addressed nucleation in a volatile-saturated liquid triggered by viscous shear, which is ubiquitous in volcanic environments. By combining laboratory experiments, theoretical analysis, and numerical simulations, we investigated the conditions under which the mechanical energy associated with shearing favors the formation and growth of gas molecule nuclei in a liquid supersaturated with volatiles. Our results reveal that the critical shear stress for nucleation decreases as the volatile supersaturation increases. Dimensional analysis applied to natural systems shows that shear-induced nucleation is likely to occur in volcanic conduits, which has implications for magma degassing processes and eruptive styles. |
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