Non-specular meteor trail echoes are radar reflections from plasma instabilities that are caused by field-aligned irregularities. Meteor simulations are examined to show that these plasma instabilities, and thus the associated meteor trail echo, strongly depend on the meteoroid properties and the characteristics of the atmosphere in which the meteoroid is embedded. The effects of neutral winds, as a function of altitude, are analyzed to understand how their amplitude variability impacts the temporal–space signatures of non-specular meteor trail echoes present in very high-frequency (VHF) radar observations. It is found that amplitudes of the total horizontal neutral wind smaller than 0.6 m s⁻¹ do not provide the right physical conditions to enable the genesis of non-specular meteor echoes. It is also found that a 0.0316 µg meteoroid traveling at 35 km s⁻¹ can be seen as a meteor trail echo if the amplitudes of horizontal neutral winds are stronger than 15 m s⁻¹. In contrast, a 0.316 µg meteoroid, traveling at the same speed, requires horizontal winds stronger than 1 m s⁻¹ to be visible as a meteor trail echo. The neutral velocity threshold illustrates how simulations show that no trail echo is created below a critical wind value. This critical wind value is not mapped directly to radar observations, but it is used to shed light on the physics of meteor trails and improve their modeling. The meteor simulations also indicate that time delays on the order of hundreds of milliseconds or longer, between head echoes and non-specular echoes, which are present in VHF backscatter radar maps, can be a consequence of very dense plasma trails being affected by weak horizontal neutral winds that are smaller than 1 m s⁻¹.

中文翻译：

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中性风对非镜面流星轨迹回波产生的影响

非镜面流星轨迹回波是由场对齐不规则引起的等离子体不稳定性引起的雷达反射。检查流星模拟以表明这些等离子体不稳定性以及相关的流星尾迹回波在很大程度上取决于流星体的特性和流星体嵌入的大气特征。分析作为高度函数的中性风的影响，以了解它们的幅度变化如何影响甚高频 (VHF) 雷达观测中存在的非镜面流星轨迹回波的时空特征。发现总水平中性风的振幅小于0.6  m s ^-1不提供正确的物理条件来启用非镜面流星回波的起源。还发现，如果水平中性风的幅度大于15 m s ^{-1 ，}则以35 km s ^-1行进的0.0316  µg流星体 可以被视为流星尾迹回波 。相比之下，一个 0.316  µg 的流星体，以相同的速度行进，需要大于 1 m s ^{-1 的}水平风 作为流星轨迹回声可见。中性速度阈值说明了模拟如何表明在临界风值以下不会产生尾迹回波。这个临界风值没有直接映射到雷达观测，但它被用来阐明流星轨迹的物理特性并改进它们的建模。流星模拟还表明，VHF 反向散射雷达图中存在的头部回波和非镜面回波之间的数百毫秒或更长的时间延迟可能是非常密集的等离子体轨迹受到弱水平影响的结果。小于1 m s ^{-1 的}中性风 。