This project will calculate the properties of relativistic turbulence using high accuracy numerical simulations, motivated by recent developments in gamma-ray burst (GRB) and gravitational wave source physics. The study involves numerical simulations of relativistic turbulence similar to recently published high resolution three-dimensional simulations of turbulent shear flows by Dr. MacFadyen and collaborators. This will produce reliable calculations of the conditions in models of prompt and afterglow GRB emission, and elucidate the conditions of relativistically turbulent astrophysical systems including compact binary mergers.
A major benefit of this work is the training of undergraduate and graduate students in the use of parallel supercomputers, thus helping the next generation of physicists and astronomers to take advantage of supercomputing, including at the petascale. Visualizations of fluid dynamics simulations have been shown to enhance science appreciation among students at all stages, including K-12, and previous results by Dr MacFadyen have appeared widely in the national and international media, including National Geographic magazine and public television's NOVA program.
Turbulence is a common everyday occurrance and can easily be seen when stirring milk into tea or coffee, or felt when on a bumpy airplane ride. The same process of turbulence is also present throughout the universe in astrophysical environments, such as exploding stars and the collision of neutron stars and black holes. These proceses often involve motions at nearly the speed of light where Einstein's theory of relativity takes over and must be included in order to understand the fundamental dynamics. Relativistic effects such as the stretching of time and the contraction of space mean that hotter gas is heavier (according Einstein's formaula E = mc2) and all waves travel within cones defined by the speed of flowing gas. All of these relativistic effects modify the dynamics of turbulent gas. This project used supercomputers to simulate the properties of relativistic turbulence. An important result of this project is the discovery that magnetic fields are quickly amplified by relativistic turbulence such that merging neutron stars may be visible due to their emission of light. This may aid in the discovery of gravitational waves, i.e. ripples in spacetime, that are also emit by these sources according to Einsteins' theory of general relativity. Multiple students at the graduate and udergraduate level learned to use some of the world's largest supercomputers in order to calculate the properties of relativistic turbulence. They produced the images seen here and also created movies which have been used to understand the properties relativistic turbulence and shown at multiple scientific conferences and public talks.
