Diffusion, Solubility, Bubble Growth, and Gas-Driven Eruptions

9972937张燃气火山和湖泊喷发是破坏性自然灾害之一。火山喷发是一个复杂的过程，涉及一个大系统和许多组成过程。我们调查的长期目标是了解火山喷发并减轻危险。继我们早先在实验模拟和理论模拟喷发过程中所做的工作之后，我们计划在下一阶段的调查中重点研究气泡增长和破碎，这是火山喷发中的两个关键组成部分过程。气泡的增长推动了喷发的早期阶段，并为后期的猛烈喷发提供了超压气体。碎裂是火山喷发的一个定义点，它会将缓慢的气泡状液体流动转变为携带岩浆颗粒的剧烈气体流动。将进行实验以研究水在流纹岩熔体中的扩散、低压下的溶解度和气泡的生长速率。这些数据将被用来构建适用于大范围温度和压力条件的水扩散率和溶解度模型。这样的模型和泡沫增长数据将被用来检验我们对泡沫增长的物理理解，包括所有输入数据的一致性。在最大应力理论的基础上发展了一个破碎判据，并将其应用于圆顶坍塌(一个破碎过程)引起的火山碎屑流。人们希望，这些发展将大大提高我们对火山喷发的了解。

9972937 ZhangGas-driven volcanic and lake eruptions are one of the destructive natural hazards. An eruption is a complex process involving a large system and many component processes. The long-term goal of our investigation is to understand the eruptions and to mitigate the hazards. Following our earlier work in experimental simulations and theoretically modeling of the eruption process, we plan in the next phase of investigation to focus on bubble growth and fragmentation, two key component processes in volcanic eruptions. Bubble growth drives the early stage of an eruption and provides overpressurized gas for the later-stage violent eruption. Fragmentation is a defining point in a volcanic eruption and turns a slow bubbly liquid flow to a violent gas flow carrying magma particles. Experiments will be conducted to study water diffusion in rhyolitic melts, solubility at low pressures, and bubble growth rates. The data will be used to construct water diffusivity and solubility models applicable to a large range of temperature and pressure conditions. Such models and bubble growth data will be used to examine our physical understanding of bubble growth, including the consistency of all input data. A fragmentation criterion will be developed on the basis of maximum stress theory and applied to pyroclastic flows owing to dome collapse (a fragmentation process). It is hoped that these developments will significantly improve our knowledge of volcanic eruptions.