X-ray studies of planets in our solar system

钱德拉天文台和XMM-牛顿天文台揭示了太阳系行星和彗星发出的X射线的美丽和多样性。该项目的重点是木星，有可能扩展到我们自己的地球的研究。木星的极地地区显示出明亮的软X射线极光，其中富含谱线的光谱来自大气中性粒子与本地和/或太阳风高电荷态重离子的电荷交换相互作用，在行星强大的磁场环境中加速。木星的大气层也会散射太阳X射线，因此在低纬度地区，木星的圆盘显示出与太阳耀斑非常相似的X射线光谱。该项目将利用钱德拉和XMM-牛顿数据来扩展我们目前对太阳风在木星X射线极光生成中所起作用的研究。大多数数据已经掌握，不久的将来将获得更多的数据，而JUNO航天器正在绕地球轨道运行，从而可以进行前所未有的多波长研究以及相关的远程和现场测量。太阳风电荷交换（SWCX）X射线辐射是太阳风中高电荷态离子与地球外逸层中性氢相互作用产生的，辐射强度与离子密度和中性氢密度成正比，在向阳面磁鞘和磁层尖点最强。磁层研究所与英国、欧洲、加拿大、中国和欧洲航天局的其他研究所合作，正在开发一项名为SMILE的空间使命（www.mssl.ucl.ac.uk/SMILE），专门研究这种发射，作为更好地了解地球磁层如何对太阳风的影响作出反应的一种手段。根据进度，学生可以特别研究SWCX X射线发射的预期光谱特性。

The Chandra and XMM-Newton observatories have revealed the beauty and multiplicity of X-ray emissions from planets and comets in our solar system. The project focuses on Jupiter, with the possibility of extending to studies of our own Earth. Jupiter's polar regions show bright soft X-ray aurorae, with a line-rich spectrum arising from the charge exchange interactions of atmospheric neutrals with local and/or solar wind high charge-state heavy ions, accelerated in the planet's powerful magnetic environment. Jupiter's atmosphere also scatters solar X-rays, so that at low latitudes the planet's disk displays an X-ray spectrum that closely resembles that of solar flares. The project will make use of Chandra and XMM-Newton data to extend our current studies of the role that the solar wind plays in the X-ray aurora generation on Jupiter. Most of the data are already in hand and more will be obtained in the near future, while the JUNO spacecraft is orbiting the planet, allowing unprecedented multi-wavelength studies as well as correlated remote and in situ measurements.The process of charge exchange takes place also at Earth. Solar wind charge exchange (SWCX) X-ray emission is produced in the interaction of highly charged ions of the solar wind with neutral hydrogen in the Earth's exosphere: the emission's intensity is proportional to the ion and neutral densities, so is brightest in the dayside magnetosheath and the magnetospheric cusps. MSSL, in collaboration with other institutes in the UK, Europe, Canada, China and the European Space Agency, are developing a space mission called SMILE (www.mssl.ucl.ac.uk/SMILE) dedicated to studying this emission as a means to reach a better understanding of how the Earth's magnetosphere responds to the impact of the solar wind. Depending on progress, the student could investigate in particular the expected spectral characteristics of the SWCX X-ray emission.