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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 ÌÇÐÄÆƽâ°æ (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 ÌÇÐÄÆƽâ°æ'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 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.