Interaction of Lightning Electromagnetic Pulse with the Ionosphere

闪电在地面上的影响是显而易见的，例如当一棵树被击中时。 在另一个方向，闪电也会对被称为电离层的高层大气层产生影响。 电离层位于地球表面上方，受到太阳辐射的强烈影响。 从人类的角度来看，电离层的实际影响之一是电离层在影响无线电波传播方面的作用。 研究已经确定，闪电可以通过被称为精灵、晕和精灵的扰动来影响电离层。 该奖项资助的研究将集中在闪电对降低电离层高度的影响上。 该奖项将资助一名研究生，促进下一代科学家的发展。研究人员建议研究白天和夜间条件下单个闪电中电离层反射高度变化的不同模式。这将需要获取额外的数据（至少数百个事件），特别是在夜间。研究人员预计，许多观察到的效应受到闪电放电强度的影响。这项工作将包含一个试图在建模精灵，以解释推断降低反射高度。还将研究其他一些问题：（1）反射高度的变化，作为一个函数的原因-回击峰值电流和前中风间隔，（2）之间的相关性的第一个天波和地波的幅度，和（3）对电离层反射高度的影响致密云内放电（在情况下，当它们成对发生）。 研究人员还将寻找E场频谱的差异，这些差异可能归因于有效反射高度的推断差异。

The effect of lightning at the ground is obvious, such as when a tree is struck. In the other direction, lightning also can have an impact on the layer of the upper atmosphere known as the ionosphere. The ionosphere is high above the Earth's surface and is strongly affected by solar radiation. One of the practical impacts of the ionosphere from the human perspective is the ionosphere's role in affecting the propagation of radio waves. Studies have determined that lightning can affect the ionosphere through perturbations known as elves, halos, and sprites. The research funded by this award will focus on the impact that lightning has on lowering the height of the ionosphere. A graduate student will be funded by this award, furthering the development of the next generation of scientists.The researchers propose to examine the occurrence of different patterns in ionospheric reflection height change within individual lightning flashes under both daytime and nighttime conditions. This will require acquisition of additional data (at least several hundreds of events), particularly at night. The researchers expect that many observed effects are influenced by lightning discharge intensity. The work will contain an attempt at modeling elves in order to explain the inferred lowering of the reflection height. A number of other issues will also be examined: (1) changes in reflection height as a function of causative-return-stroke peak current and preceding interstroke interval, (2) correlation between magnitudes of the first sky wave and ground wave, and (3) effect on ionospheric reflection height of compact intracloud discharges (in cases when they occur in pairs). The researchers will also search for differences in E field frequency spectra that could be attributed to the inferred differences in effective reflection heights.