A new method for determining meteoroid mass from head echo data
A new method for determining meteoroid mass from head echo data
复制标题
一种从头部回波数据确定流星体质量的新方法
DOI：
10.1029/2004ja010950
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发表时间：
2005
影响因子：
--
通讯作者：
L. Dyrud
中科院分区：
文献类型：
--
作者：
S. Close;M. Oppenheim;D. Durand;L. Dyrud
[1]头部回波是当流星体进入地球大气层时，紧邻其周围的等离子体的雷达反射；对这些等离子体的分析可以帮助确定母体流星体的固有属性，如质量。过去，流星体的质量是通过假设流星体和空气分子之间的动量守恒，利用头部回波速度和减速数据来计算的。我们把这样的质量称为“动力质量”。然而，这种方法只能在假定流星体半径或密度的情况下才能用于确定流星体质量。本文阐述了一种利用我们新的球面散射理论确定流星体质量的新方法。这一理论允许我们使用头部回声测量来计算头部回波等离子体密度。然后，通过使用已建立的公式中的等离子体密度来估计由烧蚀的流星体产生的电离物质与电离物质的比率，我们可以确定流星体的质量。我们把这种质量称为“分散质量”。我们证明了我们新的质量确定方法适用于在VHF和UHF同时探测到的头部回波，并验证了流星体质量在这两个频率下是相同的。最后，我们对动力学质量和散射质量进行了比较，结果表明，总的来说，这些方法在一个数量级内是一致的。
[1] A head echo is the radar reflection from the plasma immediately surrounding a meteoroid upon its entry into the Earth's atmosphere; analysis of these plasmas can help determine a parent meteoroid's inherent properties, such as mass. In the past, meteoroid mass was calculated using head echo velocity and deceleration data by assuming momentum conservation between the meteoroid and air molecule. We refer to such masses as “dynamical masses.” This method, however, can only be used to determine meteoroid mass if either the meteoroid radius or density is assumed. In this paper, we expound upon a new method for determining a meteoroid's mass by utilizing our new spherical scattering theory. This theory allows us to use head echo measurements to calculate head echo plasma density. Then, by using the plasma density in an established formula that estimates the ratio of unionized to ionized material produced by an ablating meteoroid, we can determine a meteoroid's mass. We refer to such masses as “scattering masses.” We show that our new mass determination method applies to head echoes detected simultaneously at VHF and UHF and verify that the meteoroid mass is the same at both frequencies. We conclude with a comparison between dynamical and scattering masses and show that in general, these methods agree to within an order of magnitude.