New Applicant Grant: Exploring the connection between solar flare energetic electrons observed at the Sun and in the heliosphere

The Solar Physics Group at Northumbria University has a long-term research programme to understand the physics of our closest star, the Sun, and other solar-like stars. The Sun displays a number of fascinating and dynamic phenomena such as powerful solar flares and giant, planet-sized concentrations of magnetic fields (sunspots). It also provides a unique window that permits us to examine in detail how stars behave.

The Sun is made of a plasma (ionised gas) threaded by a strong magnetic field. Such magnetised plasmas are common throughout the Universe (e.g. active galaxy nuclei, nebula, interstellar medium), hence our research also advances our understanding across multiple research communities.

Furthermore, we are also keen to determine how the Sun influences the near-Earth environment. The Sun is the powerhouse of our solar system and its daily variability can have profound consequences for Earth. Space Weather is the name given to the impact of events (e.g. solar flares, coronal mass ejections) from the Sun on our technologically- advanced society.

This impact is both beautiful (e.g. Northern lights) and potentially extremely detrimental (e.g. damaging satellites, increasing radiation that is harmful to aircrew and astronauts). Thus, in order to understand and address the risks associated with Space Weather, we need to understand its origins and drivers.

Our work aims to address one of STFC's Science Challenges, namely "How do stars and planetary systems develop and how do they support the existence of life?", as well as key questions in the STFC Roadmap for Solar System Research, e.g. "What are the structures, dynamics and energetics of the Sun?" and "What are the fundamental processes at work in the Solar System?".

The project focuses on solar flares, a key component of space weather, and a laboratory for studying multiple aspects of high energy astrophysics. Solar flares produce radiation at all wavelengths, and unlike other astrophysical objects, there are abundant space and ground-based observatories viewing the Sun from radio to gamma-rays, using spatially resolved, high-resolution imaging and spectroscopy alongside Sun-as-a-star observations.

Radiative diagnostics: X-ray bremsstrahlung, UV continuum, atomic line emission, and radio help us diagnose the properties of energetic particles at the Sun, and the extreme flaring plasma conditions. The Sun is the only star that permits in-situ detection of flare-accelerated electrons and ions (multi-messenger astronomy) at Earth (1 AU), and now within the Sun's corona (0.04 AU) with the successful launch of the Parker Solar Probe our "mission to touch the Sun", and the much anticipated ESA/NASA mission Solar Orbiter.

The project is interested in understanding the energetics of solar flares and how high energy particles observed at the Sun and in the heliosphere are created in the Sun's atmosphere. This will be achieved by combining a multi-wavelength and multi-messenger observational study and by creating observationally-driven models in different plasma environments at the Sun and in the heliosphere.