Electromagnetic Emissions from Energetic Charged Particles Generated by Lightning Discharges.

我们从日常生活中知道，无线电天线、无线互联网等设备，甚至从欧洲核子研究中心这样的现代同步回旋加速器中都知道，加速电子确实会以不同的频率辐射电磁波，这取决于加速电子的能量。此外，在闪电放电方面，电子不仅被加速，而且许多其他物理现象也伴随着它。它们是：电子速度可以接近光速的80%，这意味着洛伦兹因子变得很重要，因此对于发射的电磁发射必须考虑相对论效应。加速的电子可以与其他空气分子碰撞，产生新的粒子或使它们电离。此外，它们还可以跨越介质边界，导致电磁辐射发射，如过渡辐射等。该项目的目的是首先了解和清楚地描述闪电放电的物理辐射机制。其次，写出一个清晰、准确和全面的理论来解释和预测所发射的电磁辐射的大小和方向。此外，它还旨在用现有的电磁辐射理论来回答一些未知的问题。此外，当前理论和测量之间的一个有趣的不匹配是电磁辐射发射的时间。此外，还观察到电磁辐射的发生早于预测的时间间隔。为了达到所述目的，首先，在完成文献回顾后，对有关雷电放电的电磁学、波、光学和物理方面的书籍进行了一些假设和假设。其次，将最终的书面理论转化为MatLab语言，并以不同雷电能量下的等高线图(一次表示多种统计分布的不同方式)与实际数据进行比较。此外，同样的过程将被更详细地执行，直到理论和实验之间达到良好的一致。其中一个应用是英国气象局对改进他们的闪电探测系统感兴趣。因此，气象局想详细了解带电粒子的电磁辐射是如何发射的，以便它们可以针对闪电发射产生的粒子辐射相应地调整其闪电探测系统。另一方面，第二个好处将是帮助像ASIM这样的太空任务，这些任务旨在测量来自闪电放电的电离辐射，如伽马射线(不同的高频辐射)。

We know from everyday life, equipments such as radio antenna, wireless internet or even from modern Synchro-cyclotron like CERN that accelerated electrons do radiate electromagnetic waves at different frequencies depending on the energy of an accelerated electron. In addition, in terms of lightning discharges, electrons not only get accelerated but many other physical phenomena go with it as well. These are as follows: the electron speed can approach approximately 80% of the speed of light, which means the Lorentz factor become significant, hence relativistic effects must be considered for the emitted electromagnetic emission. The accelerated electrons can collide with other air molecules to create new particles or ionise them. Moreover, they can cross a dielectric boundary that causes electromagnetic radiation emissions known as transition radiation, etc. This project aims to firstly understand and clearly describe the physical radiation mechanism due to lightning discharges. Secondly, to write up a clear, precise and comprehensive theory that explains and predicts the magnitude and direction of emitted electromagnetic radiation. In addition, it also aims to answer some of the unknowns with the current electromagnetic emission theories. In addition, one of the interesting mismatch between the current theory and measurement is the timing of the emission of electromagnetic radiation. In addition, it is observed that electromagnetic radiation occurs earlier than the predicted time interval. In order to achieve the stated aims, firstly, a few hypotheses and assumptions will be made after the completion of literature review with reading books on electromagnetism, waves, optics and physics of lightning discharges. Secondly, the final version of written theories will be transformed to MatLab language, and compared with the actual data in terms of contour plots (different way of expressing many statistical distributions at once) at different lightning energies. In addition, the same procedure would be carried in more detail out until a good agreement between theory and experiment is achieved. One of the applications is that the Met office is interested in improving their lightning detection system. Hence the Met Office would like to understand in detail how electromagnetic emission from charged particles are emitted so that they can adjust their lightning detection system accordingly for that radiation from those particles that are generated by lightning discharges. On the other hand, the second benefit would be to help space missions like ASIM that aims to measure ionising radiation like gamma rays (Different high frequency radiation) from lightning discharges.