Analysis of 3D Kinetic Simulations of Meteor Trails
Analysis of 3D Kinetic Simulations of Meteor Trails
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DOI：
10.1029/2020ja028889
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发表时间：
2020-11
期刊：
影响因子：
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通讯作者：
L. K. Tarnecki;M. Oppenheim
中科院分区：
文献类型：
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作者：
L. K. Tarnecki;M. Oppenheim
雷达探测每天进入地球大气层的数十亿小流星体产生的等离子体尾迹，并返回用于推断流星体群和高层大气特征的数据。研究人员使用模型来研究轨迹的动态演变，使他们能够更好地解释雷达结果。这项研究提出了一个完全动力学的三维代码来探索三个尾迹特征的影响：长度，中性风速和消融高度。模拟表征湍流的发展轨迹的演变，这些比较雷达数据。他们还表明，中性风驱动波浪和湍流的形成，并且波浪振幅随着中性风速的增加而增加。有限尾迹模拟表明，尾迹的整体运动与中性风有关。详细分析了模拟轨迹光谱产生的频谱宽度和评估信号强度作为一个功能的角度。在所有情况下，波主要沿着尾迹的长度传播，并且大部分功率是在垂直于B方向的模式中。持续波的波长与原始尾迹的梯度尺度长度相对应。我们的研究结果表明，在米级模式中，随着海拔高度增加15 km，功率下降相对于方位角的速率从5.7 dB/度增加到6.9 dB/度。这些结果将使研究人员能够从流星的非镜面雷达观测中获得更详细和准确的信息。
Radars detect plasma trails created by the billions of small meteoroids that enter the Earth's atmosphere daily, returning data used to infer characteristics of the meteoroid population and upper atmosphere. Researchers use models to investigate the dynamic evolution of the trails, enabling them to better interpret radar results. This study presents a fully kinetic, three‐dimensional code to explore the effects of three trail characteristics: length, neutral wind speed, and ablation altitude. The simulations characterize the turbulence that develops as the trail evolves and these are compared to radar data. They also show that neutral winds drive the formation of waves and turbulence in trails, and that wave amplitudes increase with neutral wind speed. The finite trail simulations demonstrate that the bulk motion of the trail flows with the neutral wind. A detailed analysis of simulated trail spectra yield spectral widths and evaluate signal strength as a function of aspect angle. Waves propagate primarily along the length of the trail in all cases, and most power is in modes perpendicular to B⃗ . Persistent waves develop at wavelengths corresponding to the gradient scale length of the original trail. Our results show that the rate at which power drops with respect to aspect angle in meter‐scale modes increases from 5.7 to 6.9 dB/degree with a 15 km increase in altitude. The results will allow researchers to draw more detailed and accurate information from non‐specular radar observations of meteors.