First experimental observations on melting and chemical modification of volcanic ash during lightning interaction.
First experimental observations on melting and chemical modification of volcanic ash during lightning interaction.
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关于在雷电相互作用期间火山灰熔化和化学修饰的首次实验观察。
DOI：
10.1038/s41598-018-19608-3
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发表时间：
2018-01-23
影响因子：
4.6
通讯作者：
Castro JM
中科院分区：
文献类型：
--
作者：
Mueller SP;Helo C;Keller F;Taddeucci J;Castro JM
火山灰羽流中的带电现象经常导致同喷发闪电放电。闪电等离子体通道内和周围的高温有可能化学改变，重新熔化，并可能挥发喷发云中的火山灰碎片。在这项研究中，我们在实验室中实验模拟火山闪电的温度条件，并系统地研究了快速熔化对火山灰的形态和化学成分的影响。不同尺寸和成分的样品被喷射到人工产生的电弧中。实验后的灰形态包括完全熔化的球体，部分熔化的颗粒，附聚物，和泡状颗粒。高速成像揭示了在短暂的闪电灰相互作用过程中发生的各种过程，如粒子熔化和圆化，发泡和爆炸性粒子破碎。闪熔颗粒的化学分析表明，大量损失的Cl，S，P和Na通过热蒸发。元素分布模式表明对流是元素从熔滴内部向挥发物损失的边缘迁移的关键过程。对钠损失程度进行建模，得出最大熔体温度在3290和3490 K之间。我们的研究结果表明，自然闪电罢工可能是一个重要的代理人同喷发的火山灰的形态和化学处理。
Electrification in volcanic ash plumes often leads to syn-eruptive lightning discharges. High temperatures in and around lightning plasma channels have the potential to chemically alter, re-melt, and possibly volatilize ash fragments in the eruption cloud. In this study, we experimentally simulate temperature conditions of volcanic lightning in the laboratory, and systematically investigate the effects of rapid melting on the morphology and chemical composition of ash. Samples of different size and composition are ejected towards an artificially generated electrical arc. Post-experiment ash morphologies include fully melted spheres, partially melted particles, agglomerates, and vesiculated particles. High-speed imaging reveals various processes occurring during the short lightning-ash interactions, such as particle melting and rounding, foaming, and explosive particle fragmentation. Chemical analyses of the flash-melted particles reveal considerable bulk loss of Cl, S, P and Na through thermal vaporization. Element distribution patterns suggest convection as a key process of element transport from the interior of the melt droplet to rim where volatiles are lost. Modeling the degree of sodium loss delivers maximum melt temperatures between 3290 and 3490 K. Our results imply that natural lighting strikes may be an important agent of syn-eruptive morphological and chemical processing of volcanic ash.
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影响因子：
3.5
作者：
LANE, SJ;GILBERT, JS
通讯作者：
GILBERT, JS
影响因子：
2.7
作者：
CORRIGAN, G;GIBB, FGF
通讯作者：
GIBB, FGF
影响因子：
5.2
作者：
Cimarelli, C.;Alatorre-Ibarguengoitia, M. A.;Dingwell, D. B.
通讯作者：
Dingwell, D. B.
影响因子：
5.2
作者：
Behnke, Sonja A.;Bruning, Eric C.
通讯作者：
Bruning, Eric C.
影响因子：
4.6
作者：
Genareau K;Gharghabi P;Gafford J;Mazzola M
通讯作者：
Mazzola M