Nuclear Fusion Simulations at Exascale - Nu-FuSe

点击翻译按钮获取中文摘要

Current worldwide energy consumption has risen 20-fold during the 20th century and the growth rate shows no sign of saturation. Of the current 15 TW load 80-90% is derived from fossil fuels, but with peak oil imminent and coal supplies limited, a sea change in energy production is vital. Renewables will make a contribution to future energy production, but they are generally unrelated to seasonal and geographical demands – while nuclear fission raises significant environmental and political worries. Nuclear fusion, on the other hand, promises a low pollution route to generate a large fraction of the world’s energy needs sustainably. However, the scientific and engineering challenges in designing such a reactor are formidable and commercial power plants are not expected before 2050.Real progress therefore needs to be made now if fusion is to be relevant as coal and oil decline. Fusion is the energy source of the stars. Under terrestrial conditions it is the two hydrogen isotopes, deuterium and tritium which can be made to fuse most readily, and this is the key reaction in a magnetic fusion reactor. This takes place at about 10^8 K and produces a helium nucleus, a neutron, and several MeV of energy. At such temperatures the hydrogen is fully ionized and hence may be confined in a doughnut-shaped magnetic field known as a tokamak. For efficiency, the plasma must operate at a sufficiently high pressure and energy confinement time, while preserving purity of the fuel. The first two quantities are limited by instabilities whose dynamics can only be fully understood through validated, large-scale computation. At the same time, the plasma-wall interaction has to be carefully controlled to keep the plasma pure, and the wall materials chosen to maximize their lifetime. Exascale computations of key plasma physics and materials science processes will help to design, run, and interpret expensive large-scale experiments like ITER and DEMO, and speed up the realization of fusion power plants significantly.