论文标题
通过对颗粒状小行星的影响产生的地震波的传播
Transmission of a Seismic Wave generated by impacts on Granular Asteroids
论文作者
论文摘要
在本文中，我们使用软球离散元素方法代码来模拟传播并研究地震波的衰减。然后，我们将发现应用于必须触摸不同小身体表面的不同空间任务。此外，一旦冲击波转化为地震波，我们对由飞镖和Hayabusa2任务产生的高速效应影响产生的地震波也是如此。我们发现，即使在非常低的压力下，例如小行星内部存在的压力，地震速度仍然可以按数百m/s的顺序，这取决于产生波浪的冲击的速度。如实验测量所预期的那样，我们的结果表明，波速直接取决于$ p^{1/6} $，其中$ p $是总压力（限制压力加波诱导的压力）。不管系统的压力和冲击的速度（在调查范围内），能量耗散都非常高。这些结果为我们提供了一种预测地震波能够在与航天器接触时在小体面移动一些小颗粒的程度的方法。此外，这种快速的能量耗散将暗示即使是超速影响，也只能扰动自我磨碎聚集体的外层，可以在其中发生隔离和其他现象。这反过来会产生分层结构，其中已经观察到了一些证据
In this paper we use a Soft-Sphere Discrete Element method code to simulate the transmission and study the attenuation of a seismic wave. Then, we apply our findings to the different space missions that have had to touch the surface of different small bodies. Additionally, we do the same in regards to the seismic wave generated by the hypervelocity impacts produced by the DART and Hayabusa2 missions once the shock wave transforms into a seismic wave. We find that even at very low pressures, such as those present in the interior of asteroids, the seismic wave speed can still be on the order of hundreds of m/s depending on the velocity of the impact that produces the wave. As expected from experimental measurements, our results show that wave velocity is directly dependent on $P^{1/6}$, where $P$ is the total pressure (confining pressure plus wave induced pressure). Regardless of the pressure of the system and the velocity of the impact (in the investigated range), energy dissipation is extremely high. These results provide us with a way to anticipate the extent to which a seismic wave could have been capable of moving some small particles on the surface of a small body upon contact with a spacecraft. Additionally, this rapid energy dissipation would imply that even hypervelocity impacts should perturb only the external layer of a self-gravitating aggregate on which segregation and other phenomena could take place. This would in turn produce a layered structure of which some evidence has been observed
