# Parallel Computing Resources for the UK MHD Community

Lead Research Organisation: University of Warwick
Department Name: Physics

### Abstract

Virtually all material in the universe consists of an ionised gas called a plasma. Plasmas conduct electricity and interact with magnetic fields, producing many physical phenomena not easily reproduced in laboratories on Earth. The large-scale behaviour of these plasmas can be predicted by using a known set of complicated mathematical equations, called the equations of Magnetohydrodynamics (MHD). The solutions of MHD equations can describe the behaviour of plasmas in which collisions dominate the physical processes, such as (i) the generation of magnetic fields through a process known as dynamo action, (ii) the release of a staggering amount of magnetic energy in a large solar flare by magnetic reconnection, (iii) the small scale chaotic motions of turbulence in a magnetised plasma, (iv) the fact that solar atmosphere is much hotter than the solar surface and (v) the way in which gigantic eruptions of solar plasma interact with the Earth's magnetic field to produce the Aurora. When collisional effects are weak, in low-density plasmas and in problems involving short length-scales, the more fundamental kinetic equations must be solved. However, the solution of both sets of equations require extremely large computers and the best way is to link several hundred computers together and get them all working on a fraction of the large problem. These computers are called parallel computers. The UK effort in this research area is at the forefront of the worldwide effort to understand how the Sun, the Solar System and astrophysical plasmas work. While this work is essentially theoretical, it is driven by the observations of the present fleet of solar and astrophysical ground and space-based observatories.

### ORCID iD

Tony Arber (Principal Investigator)  http://orcid.org/0000-0002-9322-4913

### Publications

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Arber T (2009) THERMAL FRONTS IN FLARING MAGNETIC LOOPS in The Astrophysical Journal

Botha G (2011) CHROMOSPHERIC RESONANCES ABOVE SUNSPOT UMBRAE in The Astrophysical Journal

Botha G (2010) Thermal conduction effects on the kink instability in coronal loops in Astronomy & Astrophysics

Bushby P (2012) Convectively driven dynamo action in the quiet Sun in Geophysical & Astrophysical Fluid Dynamics

Favier B (2013) Kinematic dynamo action in square and hexagonal patterns. in Physical review. E, Statistical, nonlinear, and soft matter physics

Favier B (2013) Growth rate degeneracies in kinematic dynamos. in Physical review. E, Statistical, nonlinear, and soft matter physics

Gruszecki M (2010) Phenomenon of Alfvénic vortex shedding. in Physical review letters

Gruszecki M (2012) Intensity variations associated with fast sausage modes in Astronomy & Astrophysics

Gruszecki M (2011) Magnetoacoustic shock formation near a magnetic null point in Astronomy & Astrophysics

Gruszecki M (2011) Slow magnetacoustic waves in magnetic arcades in Astronomy & Astrophysics

Silvers L (2009) DOUBLE-DIFFUSIVE INSTABILITIES OF A SHEAR-GENERATED MAGNETIC LAYER in The Astrophysical Journal

Skinner D (2013) Double-diffusive magnetic buoyancy instability in a quasi-two-dimensional Cartesian geometry in Monthly Notices of the Royal Astronomical Society

Tsiklauri D (2011) Galaxy rotation curves: the effect of $\vec{j} \times\vec{B}$ force in Astrophysics and Space Science

Description The computations carried out with this equipment has shown us how magnetic fields play a crucial role in many astrophysical objects such as stars, accretion discs and galaxies.
Exploitation Route Our work has stimulated others to use many of our computational techniques to study astrophysical magnetic fields. The UKMHD Consortium is still an active user of UK computational resources through the STFC DiRAC facilities. As this facility under this award ended in 2012 recent publications and outcomes are now attributed to the DiRAC facility.
Sectors Education

Description This award is for a computing facility for UK MHD researchers. As well as contributing to our understanding of the role of magnetic fields in Astrophysical objects, it has also led to the development of numerical algorithms with more general application. The work of UK MHD continues but now has access to computing resources through the STFC DiRAC facility.

Description CCP Flagship Project
Amount £380,448 (GBP)
Funding ID EP/M011534/1
Organisation Engineering and Physical Sciences Research Council (EPSRC)
Sector Public
Country United Kingdom
Start 04/2015
End 03/2018

Description H2020-PROTEC-2014
Amount € 386,531 (EUR)
Funding ID 637302 - PROGRESS
Organisation European Commission
Sector Public
Country European Union (EU)
Start 01/2015
End 12/2017

Description UKMHD Consortium
Organisation University of Leeds
Department School of Mathematics Leeds
Country United Kingdom
PI Contribution Warwick was a host site for one of three HPC clusters bought for the UKMHD Consortium. The Consortium is UK wide and has over 40 members in University academic groups. Warwick managed a compute resource available for the whole consortium.
Collaborator Contribution Two additional HPC clusters were procured and managed for the UKMHD Consortium by the Universities of Leeds and St Andrews.
Impact In total across the three HPC sites procured under this grant there have been around 200 publications resulting from work done on the UKMHD Consortium clusters.

Description UKMHD Consortium
Organisation University of St Andrews
Department School of Mathematics and Statistics
Country United Kingdom