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Using Mira, physicists from Princeton Plasma Physics Laboratory (PPPL) have uncovered a new understanding about electron behaviour in edge plasma. Based on this discovery, improvements were made to a well-known analytical formula that could enhance predictions of and, ultimately, increase fusion power efficiency.

Principal investigator C.S. Chang, head of the U.S. SciDAC-3 Partnership for Edge Physics Simulation headquartered at PPPL, and co-investigator Robert Hager recently gained new insight into the properties of a self-generating electrical current that boosts power in a tokamak fusion reactor, based on simulations run on the 10-petaflop IBM Blue Gene/Q supercomputer Mira located at the Argonne Leadership Computing Facility in the US.

To develop the best predictive tools for ITER (and, by extension, other experimental fusion reactors), research teams are using high-performance computing to resolve the behaviours of fusion plasma across the many spatial scales that impact reactor efficiency and plasma stability.

Running on more than 260,000 Mira processing cores with excellent scalability, the latest XGCa plasma edge simulations revealed electron behaviours related to edge bootstrap current that are not accurately predicted for present-day tokamak geometry by the well-known Sauter formula, which is used to calculate values for the bootstrap current.

"Mira allows running simulations of larger tokamaks at ITER's scale, and modeling at much higher particle counts more accurately represents the electron populations in the plasma," said Tim Williams, Argonne computational scientist.

Read the full article on the website of the Argonne Leadership Computing Facility.

Image: Based on a series of high-resolution simulations of bootstrap current in present-day tokamak geometries, researchers have modified a well-known formula that calculates the value of bootstrap current in order to improve the prediction of fusion efficiency in tokamak reactors. Credit: Kwan Liu-Ma, University of California, Davis.

What should have been a standard two-hour visit turned out to be a four-hour crash course in fusion. For the first time in the history of the ITER Project, a 29-person delegation from the African continent came to visit ITER this week. Taking part in a conference in Marseille on public-private partnerships in the energy sector, the lawyers, engineers and ministry representatives from Cameroun, Burkina Faso, Congo, Togo, Senegal, Kenya, the Ivory Coast, Maurice, Mali and Uganda seized the opportunity to spend an afternoon at ITER Headquarters, with a visit to the site and presentations on fusion science and technology and the organization of the world's largest International scientific collaboration. "What you are doing here is really amazing," Tarek Toko, from the West African Development Bank, said on the way back to the bus. "You must succeed!"

The organization charged with overseeing and coordinating the European Union's quest for fusion power, EUROfusion, plans to update during 2016 the European Union's 2012 strategic plan to put fusion electricity on the grid by 2050, according to Xavier Litaudon speaking at the annual meeting of the Fusion Power Associates on 16-17 December in Washington, DC.

ITER remains "the key facility of the roadmap" but the update will incorporate the impact of slippage in the ITER construction schedule. A new ITER schedule is expected to be approved by the ITER Council by mid-2016 according to ITER Director-General Bernard Bigot, who also spoke at the meeting.

The European Union's strategic plan reflects a collaboration with Japan on the "Broader Approach" to fusion that was a part of the ITER siting decision process. According to EUROfusion, in the course of the roadmap implementation the fusion program will move "from being laboratory-based and science-driven towards an industry- and technology-driven venture."

To ensure minimal delay to DEMO, the next step after ITER, the European Union has initiated a conceptual design system engineering approach that will address such issues as safety, tritium breeding, power exhaust, remote handling, component lifetime and plant availability, according to Litaudon. Experience gained from continued operation and "internationalization" of the JET tokamak and from devices JT-60SA (Japan), WEST (France) and Wendelstein 7-X (Germany) are also important elements of the plan.

Ed Synakowski, head of the US fusion program, told the audience that the US had recently completed the US fusion Strategic Plan requested by Congress in 2014. Permission from Congress was needed before the Plan could be released to the public, he said.

All talks from the Fusion Power Associates annual meeting, Strategies to Fusion Power, are posted at the FIRE website.

Source:Fusion Power Associates