Joint Institute for Fusion Theory holds annual conference to discuss next-generation computing’s role in fusion energy

For nearly 40 years the United States and Japan have collaborated on making the dream of limitless clean energy a reality. In 1980 the two countries created the US-Japan Joint Institute for Fusion Theory (JIFT) to formalize this collaboration. Since that time researchers from both countries have organized workshops to share best practices, discuss the state of fusion research, and plan for the future.

The United States and Japan alternate which country hosts the conference, and this year JIFT’s annual meeting took place at the US Department of Energy’s (DOE’s) Oak Ridge National Laboratory (ORNL). This year’s theme was exascale computing—a hundredfold speedup over today’s fastest supercomputers.

“It is clear that the international effort that is magnetically confined fusion research is already taking strides to exploit exascale computing when it arrives, and the US and Japan are collaboratively leading this charge,” said ORNL physicist David Green. Green, along with other domain and computer scientists from the Oak Ridge Leadership Computing Facility (OLCF)—a DOE Office of Science User Facility located at ORNL—participated in the 3-day meeting, which ran August 17 through 19.

Participants focused on American and Japanese fusion codes, discussed their advantages and drawbacks, and worked on establishing a roadmap for making fusion research as successful as possible into the exascale era.

Fusion researchers have spent decades trying to design a large-scale fusion reactor capable of generating more energy than is needed to operate the machine. Experimental fusion reactors known as tokamak reactors are ring-shaped facilities that use electromagnetism to force very-high-temperature plasmas to spin around the ring, generating energy in the process. Researchers are essentially igniting a miniature star inside of a fusion reactor.

“The extreme conditions within fusion devices mean experimentally diagnosing the complex physical processes is incredibly difficult,” Green said. “As such, fusion researchers rely on high-fidelity computer simulation to investigate theoretical models of the device’s interior.”

The first day of the conference largely consisted of small group discussions and a tour of OLCF facilities, including the OLCF’s flagship supercomputer, a Cray XK7 named Titan.

The second day of the conference contained the bulk of the technical program, with participants hearing from experts studying plasma confinement in their simulations as well as researchers focused on how plasma interacts with the reactor itself.

The third day targeted the challenges facing the community as it prepares for exascale computers—machines capable of 100 times more performance than current-generation supercomputers.

As computers continue to become more powerful, fusion researchers will be able to take their research to new heights.

“As we approach exascale, the possibility of simulating an entire fusion device becomes real, with fusion domain scientists already working in close collaboration with computer science and architectural experts to ensure these new computing resources will help bring the goal of fusion power that much closer,” Green said.

Oak Ridge National Laboratory is supported by the US Department of Energy’s Office of Science. The single largest supporter of basic research in the physical sciences in the United States, the Office of Science is working to address some of the most pressing challenges of our time. For more information, please visit