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PhD projects in Solar Physics for our STFC studentships 2024 are listed below.
- Unveiling the Sun, next generation studies of the Sun’s magnetic activity (Prof. Lucie Green)
- Fast Magnetic Reconnection in Solar Flares – Preparing for Solar-C (Prof. Sarah Matthews)
- The Link Between Solar Coronal Heating and Particle Acceleration (Dr. Hamish Reid)
Unveiling the Sun, next generation studies of the Sun’s magnetic activity
Primary Supervisor: Prof. Lucie Green
The Sun's character is determined by its dynamic and evolving magnetic field, which harbours energy that is used to power some of the most violent and energetic events in the Solar System - coronal mass ejections. These ejections are of intense interest as they can drive major space weather impact at Earth, and space weather forecasters around the world seek to predict when an eruption will reach the Earth and what the degree of impact will be. For example, the changes these ejections produce in the near-Earth space environment can ultimately lead to disruptions to electricity distribution, communications, and navigation systems. Knowing why and when these ejections will occur are questions that are centrally important to not only understand how the Sun operates but also for developing an ability to make accurate space weather forecasts.
However, for many decades the Sun appears to produce eruptions that are detected at Earth but which are not seen leaving the Sun’s atmosphere. These are “stealthy” events and research at MSSL has shown that they may originate from high up in the Sun’s atmosphere, at the limit of where our telescopes previously were able to collect data. That was the case until the launch of ESA’s Solar Orbiter spacecraft, which provides a new set of eyes on the Sun through the EUI telescope that images the Sun’s atmosphere using extreme ultraviolet radiation and which enables a view much larger than previously possible.
In this PhD project, wide field-of-view EUV images will be used to monitor how large-scale plasma and magnetic structures evolve over time and how changes at small spatial scales are able to contribute to the large-scale evolution of the magnetic field to the point of eruption. The PhD research will employ relevant image processing techniques to identify evolutionary pathways that lead to the ejection of high-altitude coronal mass ejections. Data will be used from the Solar Orbiter mission (that was launched in 2020), in which MSSL plays a leading role, but there are opportunities to use other space-based instrumentation, such as from NASA’s Parker Solar Probe, and data from ground-based radio telescopes to provide a multi-wavelength analysis. Although based at MSSL, you will ultimately have the opportunity to work in international collaborations with our colleagues around the world to bring together the skills and knowledge needed to study the building blocks of the magnetic field that relate to coronal mass ejections and help generate knowledge that feeds into space weather forecasting.
Desired Knowledge and Skills
- Undergraduate modules in plasma physics, solar physics or astrophysics
- Strong computational skills including experience of programming in Python
Fast Magnetic Reconnection in Solar Flares – Preparing for Solar-C
Primary Supervisor: Prof. Sarah Matthews
The Sun is our closest star, and with space now firmly established as part of our society’s environment, its unique proximity has inescapable consequences for us. While its radiation provides the energy source of our whole ecosystem, our understanding of how the variations in that radiation control, e.g. our climate, still contains huge gaps. As well as the long-term variations in the solar output, the Sun exhibits a cycle of activity the constituents of which are explosive events which release energy. This explosive energy release occurs on a myriad of scales, from nanoflares to huge eruptive flares, which are accompanied by the bulk eruption of plasma and magnetic field known as coronal mass ejections (CMEs) and whose impacts can be seen globally across the Sun and throughout the heliosphere. The most extreme of these events constitute the largest examples of explosive energy release within our solar system, during which upwards of 1026 J of energy is released. Solar flares comprise a key component of space weather, and yet despite their key importance and the extensive range of observations available from space and the ground, several open questions remain.
Magnetic reconnection is the primary process by which energy release occurs in solar flares with current theories predicting that this occurs in a current sheet high in the corona. While there are many observable signatures predicted by our models, observations of the site and details of reconnection process remain a challenge, particularly spectroscopic observations. However, recent advances in modelling and new techniques for indirectly inferring the conditions in the current sheet provide further opportunities for studying this process.
The project will initially utilise existing spectroscopic data from the Hinode EIS, IRIS, Solar Orbiter EUI, SPICE and STIX instruments, as well as from ground-based telescopes where available to advance our understanding of the magnetic reconnection processes occurring in solar flares. As we move towards Solar Maximum the student will also have the opportunity to propose and acquire new observations The research undertaken will form part of the solar group’s preparatory work for the Solar C EUVST mission currently under development and scheduled for launch in 2028. The student undertaking this project would thus participate both in the international Hinode EIS and Solar C EUVST teams, including attending team meetings and collaborative visits.
Desired Knowledge and Skills
- Undergraduate or MSc degree in physics, astrophysics, or related area is desirable, but curious and motivated students with other backgrounds will also be considered.
- Previous experience of data analysis, as well as good writing and presentation skills, are also desirable but not essential.
The Link Between Solar Coronal Heating and Particle Acceleration
Primary Supervisor: Dr Hamish Reid
Our Sun’s atmosphere, the solar corona, is extremely unstable. Magnetic instabilities heat the corona to 1 million degrees and occasional explosions known as solar flares accelerate particle beams to near-light speeds. The strong magnetic fields above sunspots can cause the corona to become even hotter, up to 3 million degrees. Mini solar flares can be triggered over hours or even days, continuously accelerating particles. One would naively expect the heating above active regions to be linked to the continuous particle acceleration. However, the link between the accelerated particles and the super-heated plasma above active regions has remained elusive for many years. In part due to a lack of resolution in our telescopes.
The recent launch of ESA’s Solar Orbiter spacecraft has provided the closest, most detailed view of solar active regions through the Extreme Ultraviolet Imager (EUI) telescope. We can now observe many small-scale phenomena (1000 km is small on the Sun!), such as solar “campfires”, that are like mini solar flares, where the corona gets locally heated to 2 million degrees. We can also observe accelerated particles better than before using new-age radio interferometers like the Low Frequency Array (LOFAR). Radio waves are emitted by the accelerated particles as they travel through the hot corona and out through our solar system.
During this PhD, we will investigate the link between the small brightening events that locally heat the corona and the radio signatures of the accelerated particles. We will analyse how both signatures evolve with time and compare the spatial extent of each signature to finally show the link between small-scale plasma heating and weak particle acceleration events. Whilst space-based and ground-based imaging will be used, there is also scope to measure these accelerated particles close to the Sun using the onboard detectors of Solar Orbiter and NASA’s Parker Solar Probe spacecraft. MSSL plays an integral part of the Solar Orbiter mission and contributed towards the construction of the EUI camera. Consequently, you will be able to work directly with the EUI team and collaborate with international scientists around the world to develop and hone your research skills. There is also the opportunity to visit one of these international teams for an extended duration. Finally, there is also the possibility of simulating the propagation of these near-relativistic particle beams using our high-performance, parallelised code, to explore how much local heating is generated as these beams travel outwards from the Sun.
Desired Knowledge and Skills
- Undergraduate modules in plasma physics, solar physics or astrophysics.
- Strong computational skills including experience of programming in Python.