SciDAC DOE initiative targets heart of fusion machine
Enormous computing power and $1.2 million from the Department of Energy are expected to help researchers at Oak Ridge National Laboratory, Massachusetts Institute of Technology, and Princeton University better understand and control fusion machines
2D solution of wave electric field in a tokamak.
October 22—Fusion energy, evident in the sun and stars, is the ultimate source of power because it provides an environmentally acceptable alternative to energy generated by fossil fuels. To achieve fusion energy requires that the fuel material be heated to hundreds of millions of degrees, much hotter than the sun. Matter at such temperatures is in an ionized state called plasma.
With funding from DOE's Scientific Discovery through Advanced Computing (SciDAC) initiative, the research team hopes to obtain highly accurate methods to predict the effects of radio waves in the plasma that would be at the core of a fusion power plant. The work will build on the research of Don Batchelor, Fred Jaeger, Lee Berry, and Mark Carter of ORNL's Fusion Energy Division, and Ed D'Azevedo of the Computer Science and Mathematics Division.
"What we propose is to extend the physics capabilities of our calculations and increase the speed and resolution," Batchelor said. "When we're done, we will have developed computational tools that enable us to study the physics needed to use waves to heat and control plasma in fusion experiments and ultimately reactors."
One specific goal of the project is to increase the dimensionality of the computer models. This involves computing the radio waves' interaction with plasma in two and three dimensions. Until now, scientists have had to make calculations that take into account just one or marginally two dimensions.
"In the past, we had to make simplifying assumptions about the physics," Batchelor said. "With this kind of computing ability, we can handle far more complex equations that give us a more accurate picture of the plasma waves across an entire plasma cross-section."
"Besides heating the plasma in much the same way a microwave oven heats food, experiments show that radio waves can drive electric currents through the plasma and force the plasma to flow," Batchelor said. "With these waves, we think we can improve the ability of the magnetic field to hold the energetic particles and plasma energy inside the device. This will be by reducing turbulent fluctuations in plasma velocity and pressure brought on by the high plasma energy."
Making many of the advances possible is ORNL's IBM supercomputer, which by this fall is expected to reach speeds of 4 trillion operation per second (4 teraflops). That kind of computing power allows scientists to write computer programs and solve problems that simply could not be solved before.
The supercomputer is part of ORNL's Center for Computational Sciences, one of two DOE high-performance computing research centers established in 1992 as part of the federal high-performance computing and communications initiative. Goals of the initiative include utilizing and moving to maturity state-of-the-art computing systems, using high-performance computing to help solve "grand challenges" and increasing the use of high-performance computing in the industrial sector.
Others involved in the project are Mission Research Corp., CompX and Lodestar Research Corp.—by Ron Walli
The Department of Energy's Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time.