Researchers are using the Jaguar supercomputer at ORNL to better understand turbulence in the cosmos.
Turbulence has always been a major unsolved problem in physics, and in the realm of space physics it’s a particularly important one,” said University of Iowa astrophysicist Gregory Howes. A team led by Howes is pursuing this mystery on Oak Ridge National Laboratory’s Jaguar supercomputer. The team was allotted time through the Innovative and Novel Computational Impact on Theory and Experiment, or INCITE, program. The project initially used the GS2 code, which computes the behavior of ions and electrons in a doughnut-shaped tokamak fusion reactor. To make the application more useful for space plasmas, Howes’s team stripped the code of its tokamak geometry, creating a faster simulation code with shorter development time. The resulting code—called AstroGK—was completed in 2007 and is routinely run using 51,000 of Jaguar’s 224,000 processing cores.
Unlike the more familiar turbulence of wind and water, astrophysical plasmas have a combination of characteristics that require a kinetic, rather than a fluid, description of the plasma. Astorphysical plasma particles rarely collide, travel at different speeds, and tend to bounce around erratically and independently within the plasma, adding another three-dimensional behavior that must be accounted for.