SCIENTIFIC SIMULATION INITIATIVE FOR FUSION ENERGY SCIENCE 3-D Plasma Simulation on New MPPs

Turbulence reduction via sheared plasma flow (A), compared to case with flow suppressed (B). Results obtained using full MPP capabilities Fusion is the power source of the sun and other stars. It occurs when forms of the lightest atom, hydrogen, combine to make helium in a very hot (100 million degrees centigrade) ionized gas or " plasma. " In this process a small amount of the matter involved in the reaction is converted to a large amount of energy. On earth, fusion could provide a safe, environmentally benign and affordable long-term energy source. Recognizing the potential of fusion energy, the President's Committee of Advisors on Science and Technology (PCAST) designated fusion as an integral component of the nation's long-term research portfolio for national energy security and climate change remediation. Fusion research in the U.S. will be revolutionized by greatly enhanced simulation and modeling capabilities made accessible by terascale computing. Since effective prediction of the properties of energy producing fusion plasma systems depends on the integration of many complex phenomena spanning vast ranges of time and space scales, advanced scientific computing in tandem with theory and experiment is a vital new tool for discovery. This will enable optimum use of innovative national experiments and support participation in large-scale international facilities. The expected acceleration in scientific understanding and innovation will help provide the scientific foundations needed for key decisions in the 2003–2004 time-frame on major new facilities in this area of research. The scientific community's recognition of the importance of a strong U.S. computational effort in fusion plasma research is evident in the recent report from the DOE/NSF Workshop on Advanced Scientific Computing held at the National Academy of Sciences. Building upon a prominent history of advanced computation, which can be traced back to the establishment of the predecessor to the National Energy Research Scientific Computing Center (NERSC) nearly 25 years ago, the U.S. fusion community has been rewarded by impressive advances in the simulation and modeling of plasma behavior. A good example is the effective use of the full power of the most advanced civilian supercomputer at NERSC to produce 3-dimensional particle simulations of turbulence suppression, which is illustrated in the figure on the cover. These calculations, which typically utilized 400 million particles, showed full scalability for 512 processors, indicating a clear path forward to efficient future use of more powerful parallel computers. Such advanced simulations, which help identify and interpret …