PhD projects in the Solar Physics group at UCL MSSL

This year we have two PhD projects available in Solar Physics at UCL’s Mullard Space Science Lab.

Please see details below or at
http://www.ucl.ac.uk/mssl/research-degrees/research/projects2015/solar-projects ,
and the details of how to apply (and other information) at
http://www.ucl.ac.uk/mssl/research-degrees

Understanding the pre-flare trigger
Prof Louise Harra

Solar flares are the most energetic phenomena in the solar system, releasing their energy in just minutes. They have an impact on the the Earth’s atmosphere and can disrupt satellites. Spacecraft are used daily by us to communicate, make business transations, and travel. This project is to understand the trigger of solar flares. It is known that magnetic complexity and magnitude are all factors that lead to large flares. But it is not know what exactly triggers a flare, and when exceptionally large ones will occur. At the peak of this solar cycle, we now have an extensive database of flares that have been observed spectroscopically with the Hinode EUV spectrometer. This allows us to explore the dynamics in the corona. The recently launched IRIS spacecraft studies the mysterious chromosphere spectrscopically and we now have a number of examples of flares being observed simulateously with the two spacecraft. This project will involve analysis of these datasets to produce the physical characteristics that lead to a solar flare occurring.

The Sun’s eruptive atmospheric magnetic field
Dr. Lucie Green, Prof. Lidia van Driel-Gesztelyi, Dr. Gherardo Valori

In the last two decades we have come to understand that the near-Earth space environment is strongly influenced by solar activity, i.e. our magnetic field and atmosphere are frequently disturbed by bursts of plasma, magnetic field and radiation that originate on the Sun. This solar activity can ultimately lead to damage to instruments onboard satellites and spacecraft, can generate electricity black-outs, and threaten the health of airlines passengers flying over polar routes. The study of such an interlinked Sun-Earth system is known as ‘space weather’.

This project will progress our understanding of the type of solar activity that creates the most severe space weather – coronal mass ejections. These ejections send vast bubbles of magnetic field into the Solar System at speeds up to around 2500 km/s. In particular, the project will study the magnetic field of the source regions of coronal mass ejections on the Sun. Indirect information about the source region magnetic field will be obtained by using extreme-ultraviolet (EUV), radio, and soft-X-ray images of the Sun’s atmosphere as the magnetic field traps hot plasma that radiates at these wavelengths. These observations will then be complemented with a modelling technique known as force-free field extrapolations. These extrapolations are created using the magnetic field measured at the photosphere and from this the atmospheric magnetic field is computed. Together, the observations and models will allow the magnetic field to be studied which in turn will reveal why the magnetic field suddenly erupts to form a coronal mass ejection.

This project is suitable for a student with an interest in magnetised plasmas with strong mathematical and physics knowledge and is funded by the Leverhulme Trust. Please find more information at http://luciegreen.com/phd-students/ .