The HPC-FF platform and team – along with the High Level Support Team – have been invaluable to the European fusion theory community. They have facilitated many important scientific discoveries, including an explanation of the observed reduction of ion profile stiffness at the JET tokamak. This effect has striking consequences, in particular, for burning plasma experiments and is likely to enhance ITER’s predicted fusion performance.

Dr. Frank Jenko, IPP

The microtearing instability shown in this image is one of the most challenging types of turbulence to simulate. (Image: H. Doerk, IPP)

The microtearing instability shown in this image is one of the most challenging types of turbulence to simulate. (Image: H. Doerk, IPP)

After having served European fusion research for four years, the High Performance Computer for Fusion (HPC-FF) completed operation in June 2013. HPC-FF provided scientists with a significant increase in computing power (100 teraFLOPS), allowing advances in plasma and materials modelling and fusion technology simulations. The European Commission (EURATOM) funded HPC-FF together with EFDA and the Forschungszentrum Jülich whose Supercomputing Centre operated the facility. Now fusion modelling work has moved to the significantly more powerful Helios computer which has a peak performance of around 1500 teraFLOPS. Helios is a Japanese-European facility under the Broader Approach agreement and is located in Rokkasho, Japan.

Turbulence simulations: a key application

Altogether, more than 200 projects were run on the HPC-FF. One of the major activities were simulations of plasma turbulence for a range of fusion devices. Turbulence is the key process governing energy confinement in tokamak plasmas. Simulating turbulence in fluids is already a demanding task, but simulating in plasmas brings the additional complexity of charged particles in an electro-magnetic field. The processes also take place on a broad range of time and length scales, and detailed simulations therefore require the use of High Performance Computers. Another important field of investigation, for which HPC-FF was used, was for studies of plasma instabilities. These phenomena can cause rapid energy losses in the plasma, which in large machines like ITER could result in damage to the reactor wall. A third focus of activity was the simulation of the behaviour of potential reactor wall materials under high-energy neutron flux. These conditions are characteristic for the deuterium-tritium plasmas that will be used in the second phase of the ITER experiment and in future fusion demonstration and power plants.

High Level Support Team continues to provide assistance

HPC-FF is the first shared High Performance Computer facility for the European fusion community. To ensure maximum benefit from the facility, a High Level Support Team was put in place. Its role is to help scientists optimise their codes for the massively parallel computer architecture of HPC-FF. The team consists of a core group based at IPP Garching and other support staff provided by the Associates. All members are HPC experts with a background in developing large scientific applications, including particular expertise in numerical algorithms and in graphical support and visualisation. The High Level Support Team will continue to provide invaluable assistance to the European fusion scientists using the Helios system and thus ensure a smooth transition to the new facility.

The “Broader Approach” agreement for complementary research and development was signed in February 2007 between EURATOM and the Japanese government. It provides a framework enabling Japan to conduct research and development over a period of ten years to support ITER.
more on the “Broader Approach” agreement