Space Environment Physics group, Physics & Astronomy

极光是带电粒子(电子和质子)沿地球磁力线移动并与中性大气相撞的结果。这些碰撞电离和激发高层大气的组成原子和分子，这可能对该地区的化学和气候产生重要影响。高能粒子沉淀产生的NOx和Hox引起了中层大气臭氧浓度的显著变化。与极光相关的电流也会引起电离层和中性大气的加热。南安普敦的空间环境物理小组最近开发了一种技术，利用位于北极高地的一台先进光谱仪观测到的极光和气辉发射，同时测量3个不同高度的中性温度。该博士项目有三个主要目标：1)进一步开发这项新技术，使其在不需要人工输入的情况下自动应用，同时仍能产生可靠的结果；2)利用新技术设计具有测量高层大气中性温度的特定功能的原型仪器；3)研究中性温度对不同极光过程和不同“空间天气”条件的响应。方法：该项目将使用位于北极高海拔斯瓦尔巴特群岛的两台最先进的光学仪器(“ASK”和“HiTIES”)。HiTIES(高通量成像回声光谱仪)是一种先进的光谱仪，使用我们的工业合作伙伴HORIBA UK Ltd.提供的定制马赛克滤光片，可以在多个不连续的波长区域以高分辨率(0.1 nm)记录光谱。一项新开发的技术使用HiTIES观测来同时测量电离层3个高度的中性温度。在这一项目中，新技术将与自动校准光谱的算法相结合，并将自动执行几个“质量控制”步骤，从而无需人工输入即可可靠地应用该技术(目标1)。将与我们的工业伙伴(目标2)合作，专门为测量电离层中性温度设计一种新仪器。ASK(极光结构和动力学)由三个高灵敏度相机组成。与电离层模型相结合，ASK观测允许对极光电子沉淀的能量和通量进行成像，这对于理解动态、精细的极光结构物理来说是一个极其强大的工具。同时进行的ASK和HiTIES观测将用于研究极光的特定性质如何影响中性温度(目标3)。

The aurora is a result of energised charged particles (electrons and protons) travelling down the Earth's magnetic field lines and colliding with the neutral atmosphere. These collisions ionise and excite the constituent atoms and molecules of the upper atmosphere, which can have important implications for the chemistry and climate of the region. The production of NOx and HOx by energetic particle precipitation has been shown to cause substantial changes in ozone concentration in the middle atmosphere. The electric currents associated with the aurora can also cause heating of the ionosphere and neutral atmosphere. The Space Environment Physics group in Southampton has recently developed a technique to measure the neutral temperature at 3 different altitudes simultaneously using aurora and airglow emissions observed by an advanced spectrograph located in the high Arctic. This PhD project has 3 main aims: 1) to further develop this new technique so that it can be automatically applied with no human input while still producing reliable results; 2) to design a prototype instrument with the specific function of measuring the neutral temperature in the upper atmosphere, using the new technique; 3) to study how the neutral temperature responds to different auroral processes and different "space weather" conditions.Methodology: This project will use two state-of-the-art optical instruments ("ASK" and "HiTIES") situated on Svalbard, in the high Arctic. HiTIES (High Throughput Imaging Echelle Spectrograph) is an advanced spectrograph which can record spectra at high resolution (0.1 nm) in multiple non-contiguous wavelength regions, using custom mosaic filters supplied by HORIBA UK Ltd., our industrial partner. A newly developed technique uses HiTIES observations to measure the neutral temperature simultaneously at 3 altitudes in the ionosphere. During this project, the new technique will be combined with an algorithm for automatically calibrating the spectra, and several "quality control" steps will be automated, so that the technique can be reliably applied with no human input (aim 1). A new instrument will be designed specifically for measuring ionospheric neutral temperature, in collaboration with our industrial partner (aim 2). ASK (Auroral Structure and Kinetics) consists of three highly-sensitive cameras. In combination with an ionospheric model, the ASK observations allow the energy and flux of auroral electron precipitation to be imaged, which makes an extremely powerful tool for understanding the physics of dynamic, fine-scale auroral structure. Simultaneous ASK and HiTIES observations will be used to study how specific properties of the aurora affect the neutral temperature (aim 3).