论文标题
在火星尘埃中，通过短暂的低压提升晶粒
Lifting Grains by the Transient Low Pressure in a Martian Dust Devil
论文作者
论文摘要
将灰尘和沙子抬到稀薄的火星气氛中是一个具有挑战性的问题。已经提出了尘埃魔鬼的大气压力偏移来支撑举重。我们在实验室实验中验证了这一想法。沿50至400 $ \ rmμm$的粒子层施加了最大少数PA的压力差。作为样品，我们使用了$ \ sim $ 50 $ \rmμm$ $ $ $ $ $ $ $ \ sim $ \ sim $ 20 $ \ rmμm$ $的玻璃珠。空气的总环境压力设置为600 pa。颗粒在压力差的低至2.0 $ \ rm \ pm $ 0.8 pa。的压力差异。在玻璃珠的情况下，弹出的晶粒返回到粒子床可能会触发新的粒子弹出，因为它们会减少凝聚力并从其他晶粒中释放出张力。因此，很少有撞击谷物足以在较低的压力差异下维持尘埃中的灰尘升起。粒子提升需要非常薄的$ \ sim $ 100 $ \ rmμm$，在支撑地面上，在较大的孔隙空间的基础上，低渗透性颗粒层。假设这一点，我们的实验支持了这样一种观念，即火星尘埃中的压力偏移从地面释放出晶粒。
Lifting dust and sand into the thin Martian atmosphere is a challenging problem. Atmospheric pressure excursions within dust devils have been proposed to support lifting. We verify this idea in laboratory experiments. Pressure differences up to a few Pa are applied along particle layers of 50 to 400 $\rm μm$. As samples we used glass beads of $\sim$50 $\rm μm$ diameter and irregular basalt grains of $\sim$20 $\rm μm$ in size. The total ambient pressure of air was set to 600 Pa. Particles are ejected at pressure differences as low as 2.0 $\rm \pm$ 0.8 Pa. In the case of glass beads, the ejected grains returning to the particle bed can trigger new particle ejections as they reduce cohesion and release the tension from other grains. Therefore, few impacting grains might be sufficient to sustain dust lifting in a dust devil at even lower pressure differences. Particle lift requires a very thin, $\sim$100 $\rm μm$, low permeability particle layer on top of supporting ground with larger pore space. Assuming this, our experiments support the idea that pressure excursions in Martian dust devils release grains from the ground.
