Armagh Observatory Gains Time on Large Cross-Border Supercomputer

Professor J. Gerry Doyle, who leads the Solar Physics research group at Armagh Observatory, has obtained a massive 12 Terabytes (12 TB) of science data from his recent observations of the Sun in collaboration with colleagues using the Swedish Solar Telescope (SST) on the island of La Palma. The computational problem of reducing such a large amount of data is far too much for one PC, or even several PCs working together, but instead requires access to a supercomputer.

Gerry Doyle has been working in collaboration with the Dublin Institute for Advanced Studies (DIAS) to obtain 2 million CPU hours (more than 200 years of central processing unit time) on the €4M supercomputer facility, FIONN, operated by the Irish Centre for High End Computing (ICHEC). Even using 1,000 of FIONN’s nearly 8,000 processors simultaneously, this massive solar physics project will take several months to reduce the raw science data into a form more suitable for scientific research.

Solar physics is one of the largest single areas of current astronomical research. Work in this field is driven by the need to better understand our Sun, the nearest star, not just because it provides unique insight into the surface evolution and lives of other stars but also because of the effects of the solar wind, and of coronal mass ejections and phenomena such as solar flares, on the inner planets of the solar system, including our Earth. These variable and still largely unpredictable influences of the Sun on the Earth are known as Space Weather.

Over the last decade, research in this area of astronomy has benefited greatly from the nearly continuous, high-resolution observations of the Sun being obtained by new telescopes and instrumentation carried by Earth-orbiting and Sun-orbiting spacecraft and from ground-based instruments such as the SST on La Palma. This has led to a wide range of observations of new phenomena, and of a wealth of rapidly evolving dynamic features on the surface of the Sun, which have to be sorted into different characteristic types of phenomena before trying, theoretically, to understand explain their origins and to understand their detailed physical evolution.

The aim of Gerry Doyle’s current research is to investigate the role played by small-scale disturbances, or transients, in coupling the relatively cool (lower) and relatively hot (upper) parts of the solar chromosphere. The chromosphere, which ranges in temperature from around 4,500 degrees Kelvin (K) to 20,000 K, has a thickness of around two thousand kilometres and lies just above the 500-km thick visible part of the Sun’s atmosphere known as the photosphere, which has an average temperature of around 6,000 degrees Kelvin (K). Above the chromosphere lies a layer a few thousand kilometres thick known as the Transition Region, which joins these relatively cool, lower parts of the Sun’s outer atmosphere on to a very much hotter, and still more puzzling, region known as the solar corona. The corona has a very low density but a temperature of several million degrees Kelvin. Its intricate structures can be observed from the ground during the few minutes of a total solar eclipse.

With the ever-increasing spatial resolution provided by new telescopes and instrumentation, astronomers have discovered that even the larger dynamic events, such as explosive flares, display amazing and intricate fine structure, and that the Sun’s magnetic field plays a key role in all these phenomena. For example, the magnetic field helps to guide the propagating plasma waves which couple into observed mass and energy outflows. The magnetic field can also dissipate its enormous stored energy into thermal and kinetic energy of electrons and plasma particles through a poorly understood process known as magnetic reconnection.

Exactly how these conceptually distinct energy transport and energy dissipation mechanisms (propagating waves and magnetic reconnection) are triggered, and how they interact with one another to produce the observed coronal heating (to millions of degrees K) and accelerate the solar wind to speeds of hundreds of kilometres per second, is still not understood.

Director of the Armagh Observatory, Professor Bailey said, "I congratulate Gerry Doyle first for his success in obtaining these unique observations of the Sun and secondly for obtaining, with Professor Tom Ray in DIAS, the essential allocation of peer-reviewed computer time necessary to analyse, within a reasonable time-frame of just a few months, the vast quantity of raw data he and his collaborators have acquired. This project provides an excellent example of cross-border scientific collaboration, showing how astronomers at Armagh work with others in many countries and, in particular, with colleagues on the island of Ireland."

The outcomes of this research, which may appear esoteric and far removed from everyday life, will help astronomers understand the surface layers of stars other than the Sun; will help to guide our understanding of hot, magnetised plasmas, an essential first step in the development of new energy sources based on the energy-generation mechanism of the Sun, namely nuclear fusion; and will help us to understand the evolution of our own Sun and the effects of its interactions — namely Space Weather — with the Earth.

Advanced computational modelling plays an increasingly important role in modern science and engineering — and is increasingly recognised as the third pillar of scientific inquiry following theory and experiment. Over the past few years, staff and students at Armagh and Queen’s University Belfast have benefited greatly from various courses given in Armagh by ICHEC on the use of HPC resources. Astronomers at Armagh have used FIONN and its predecessor before: for work programmes ranging from solar and stellar astrophysics to the long-term orbital evolution of comets and asteroids in the solar system. However this is the Observatory's first major application of ICHEC resources, and the Observatory thanks ICHEC and DIAS for facilitating this use of such a powerful facility.

The name FIONN comes from the Irish Fionnachtana — which means "the action of discovery". It was chosen from a competition run for primary and second-level students in Ireland and aptly describes the work carried out on the machine. FIONN was co-funded by Science Foundation Ireland (SFI) at a level of €3.7M and with additional industry funds totalling €450k.

ICHEC was founded in 2005 as Ireland's national high performance computer centre. Its mission is to provide High-Performance Computing (HPC) resources and support to academic and allied institutions, as well as education and training for researchers in third-level institutions throughout the island of Ireland. By achieving its mission of technology transfer and enablement, it supports Irish industries large and small to contribute to the development of a high value-added economy. In the same way, Armagh Observatory’s astronomical research has important spin-off for the economy both in terms of capacity building and education and training.

FOR FURTHER INFORMATION PLEASE CONTACT: Gerry Doyle at the Armagh Observatory, College Hill, Armagh, BT61 9DG. Tel.: 028-3752-2928; FAX: 028-3752-7174; jgdat signarm.ac.uk.

Last Revised: 2015 January 5th