Global exploration of the upper atmosphere of Mars using radio occultation measurements

使用无线电掩星测量对火星高层大气进行全球探索

• 批准号: 2614496
• 金额: --
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2614496
• 关键词: Global; exploration; upper; atmosphere; Mars

The structure of the upper atmosphere of Mars has long remained poorly known, with only sporadic measurements available until recently, when Nasa's MAVEN and ESA's Mars Express and ExoMars spacecraft visited the planet with the relevant instrumentation to explore regions above 100 km in the atmosphere. The planet's ionosphere was explored using the technique of radio occultations, whereby a radio signal emitted from the spacecraft is traced and measured by the Deep Space Network as the spacecraft disappears behind the planet. This techniques allows vertical profiles of electron densities to be inferred, but by nature of the geometry only the dawn and dusk regions can be sampled, not the dayside and nightside regions which are known to be crucial for our understanding of chemistry and transport processes (winds). To overcome this limitation, ESA recently trialled for the first time ever at Mars spacecraft-to-spacecraft occultations, sampling any region, the dayside and the nightside. The PhD project will consist in exploring this new dataset which will be made available to us and analysed by the PhD student. He will start with a technique he previously developed during his time at ESA and build on that in order to obtain a robust and reliable technique for reducing past and future datasets. Thereby, the student, in addition to having developed a methodology which can be used in future planetary explorations, will obtain a dataset of ionospheric electron densities which can be further investigated for structural anomalies, including the effects of Mars' crustal magnetic fields on ionospheric structures and, by using and further developing chemistry and transport models available in the group, contribute towards identifying the main processes shaping the ionosphere of Mars.

长期以来，火星上层大气的结构一直鲜为人知，直到最近，NASA的Maven和ESA的Mars Express和Exomars航天器就可以使用相关仪器来探索大气中超过100 km的区域。使用无线电掩星技术探索了行星的电离层，当航天器在行星后面消失时，从航天器发出的无线电信号被从航天器发出和测量。这些技术允许推断电子密度的垂直曲线，但是从几何学的性质上讲，只能采样黎明和黄昏区域，而不是众所周知，这对于我们对化学和运输过程（风）的理解至关重要。为了克服这一局限性，ESA最近在火星飞船到空中固有宣传活动中首次试用，对任何区域，时代和夜间进行了采样。博士项目将包括探索这个新数据集，该数据集将为我们提供并由博士生分析。他将从他在ESA期间先前开发的技术开始，并以此为基础，以获得一种可靠的可靠技术来减少过去和将来的数据集。因此，该学生除了开发出一种可以在未来的行星探索中使用的方法，还将获得一个电离层电子密度的数据集，可以进一步研究结构异常，包括Mars的地壳磁场对电离层结构和进一步开发的化学和运输模型的贡献，该过程促进了该小组的贡献。