The XMM-Newton and Chandra observatories have revealed the beauty and multiplicity of X-ray emissions from planets and comets in our solar system. MSSL has a vibrant research programme in this field which encompasses planetary physics, solar science and the response of solar system objects to the impact of the Sun’s activity. The project on offer focuses on two themes, our own Earth and Jupiter. The fraction of work dedicated to each is flexible and will be decided in discussions with the supervisors.
The process of charge exchange between ions and neutral particles has been studied since the dawn of atomic physics, but it took until about 20 years ago for it to be recognized as an important contributor to the production of soft X-rays in astrophysical sources. It was first found to be responsible for the bright X-ray emission of comets as they travel near the Sun. In this case we are talking of solar wind charge exchange (SWCX), which is produced in the interaction of highly charged ions of the solar wind with the extended neutral comae of the comets. We now know that SWCX takes place also at Earth when solar wind ions interact with neutral hydrogen in the Earth’s exosphere. The emission’s intensity is proportional to the ion and neutrals densities, so is brightest in the dayside magnetosheath and the magnetospheric cusps. Evidence for this has been provided by XMM-Newton when viewing along lines of sight crossing the terrestrial magnetosphere. 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 the SWCX emission as a means to reach a better understanding of how the Earth’s magnetosphere responds to the impact of the solar wind. The PhD project involves simulating and investigating the X-ray maps of the magnetosheath and magnetospheric cusps expected to be returned by the Soft X-ray Imager onboard SMILE and also relating them to the UV images of the Northern aurora that SMILE UV Imager will produce.
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. At energies above ~3 keV the X-ray spectrum of the Jovian aurora becomes featureless, pointing to an origin from electron bremsstrahlung. 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. This is a particularly exciting time to investigate Jupiter’s X-ray emissions because of the presence at the planet of the Juno spacecraft which has been orbiting Jupiter since July 2016, making measurement in situ and allowing unprecedented multi-wavelength studies (see an example on the right of Chandra auroral X-rays overposed on the optical image from Juno) as well as conjugate remote and in situ measurements which directly relate to the state of the Jovian magnetosphere. Already an exceptional amount of new knowledge about the physical drivers of the auroral X-ray emission has derived from joint measurements by Juno and remotely by XMM-Newton and Chandra. A large amount of X-ray data is in hand and available for further in depth investigations and the PhD project will be centred on their analysis and interpretation.
Desired Knowledge and Skills
• Undergraduate in planetary science, astrophysics or physics
Applications submitted by 31st January 2020 will be given full consideration. We will continue accepting applications until all places are filled. After we receive your application, we will select candidates for interviews. If you are selected, you will be invited for an interview at MSSL. You will have the opportunity to see the laboratory, students' flats and talk to current students. The studentships are for the advertised projects only. In your application, please specify which project you want to apply for.
To apply, please visit the Online Application page, select department of "Space & Climate Physics" and programme type of "Postgraduate Research". After pushing "Search Now" button, select "RRDSPSSING01: Research Degree: Space and Climate Physics" for Full-time or Part-time mode.
Our Online Applications page can be found here: https://www.ucl.ac.uk/adminsys/search/
An upper second-class Bachelor’s degree, or a second-class Bachelor’s degree together with a Master's degree from a UK university in a relevant subject, or an equivalent overseas qualification.
Students from the UK or those from the EU who meet the residency requirements (3 years' full-time residency in the UK) are potentially eligible for a Science and Technology Facilities Council (STFC) studentship.