Research Fellows Directory
Professor David Hughes BSc, PhD
University of Leeds
In the most general terms, I am studying the generation and dynamical behaviour of astrophysical magnetic fields. Magnetic fields are ubiquitous in nature, being detected in planets, including the Earth, in stars, including the Sun, in accretion discs and in the interstellar medium. However, the means by which these magnetic fields are maintained is far from understood, and it is this particular question that I am primarily addressing.
It is accepted that cosmical magnetic fields are maintained by some sort of dynamo mechanism in which the motions of the electrically conducting plasma in stellar interiors, or the electrically conducting liquid metal in planetary interiors, “wind up” the magnetic field, thus reinforcing it against its tendency otherwise to decay. A striking feature is the presence of large-scale magnetic fields – such as the field that gives rise to the 11 year solar cycle – in which the scale of the magnetic field is large in comparison with the scale of the underlying fluid motions. Understanding the details of the process of large-scale field generation remains one of the great challenges in astrophysical magnetohydrodynamics. I am addressing this problem via a combination of analytical and computational approaches, for the latter taking advantage of modern massively parallel computational facilities.
Magnetic fields are responsible for a vast range of astrophysical phenomena. On the Sun. for example, they are the cause of sunspots, solar flares and coronal mass ejections. The aim of my work is thus to enhance our understanding of a physical process (magnetohydrodynamic dynamo action) that is at the very heart of astrophysical magnetism. Understanding the solar dynamo mechanism will, moreover, help in the understanding and forecasting of space weather, which is extremely important for safeguarding satellites and also certain terrestrial facilities.