Computational and theoretical (magneto)-hydrodynamics

Gases and plasmas are much more common in astrophysics than solids or liquids. Stars are large spheres of ionized gas, or plasma, held together by their own gravity. The space between the stars is filled with the interstellar medium that contains all phases of gas ranging from molecular clouds, atomic gas, and ionized plasma. Galaxy clusters have atmospheres of hot plasmas.

In essence, the conservation of mass, momentum, and energy determine how gases move. This may sound deceptively simple, but leads to complex phenomena such as turbulence, instabilities and mixing. In combination with magnetic fields, gas and plasma motions lead to spectacular phenomena such as solar flares, sunquakes, and jets from accretion disks around black holes and other compact objects. Nuclear and chemical reactions will determine the composition of the gas. Once we know the elemental composition of the gas or plasma, quantum physics tells us how the ions, atoms, and molecules interact with light,  which can cool the gas via radiation or heat the gas via absorption of light. Gravity will tell the gas how to clump and form stars, galaxies and the cosmic web.

The underlying physics of instabilities and mixing, heating and cooling, and reaction rates, are relevant not only in astrophysics but right here on Earth too. For example, how layers of ocean water of different salinity and temperature mix impacts global climate. How pollutants are transported in air or water is of interest for ecosystems and public health. The physics of a petrol-air flame front in the cylinder a combustion engine is very similar to the nuclear flame front in a supernova explosion. The principles of observing matter in space and monitoring machining and production processes are related.

At the E.A. Milne Centre we develop numerical and theoretical models of fundamental hydro- and magneto-hydrodynamics processes along with studying their applications in astrophysics and beyond. These computational and theoretical studies make extensive use of the University of Hull’s Viper High Performance Computing (HPC) cluster.