For the first time, scientists have been able to simulate the spontaneous transition of turbulence at the edge of a fusion plasma to the high-confinement mode (H-mode) that sustains fusion reactions. The detailed simulation is the first basic physics, or first-principles-based, modeling with few simplifying assumptions.
“After 35 years, the fundamental physics of the bifurcation of turbulence into H-mode has now been simulated, thanks to the rapid development of the computational hardware and software capability,” explained Dr. C.S. Chang, the first author of the Physical Review Letters paper [118, 175001 (2017)] that reported the findings. The co-authors included a team from PPPL, the University of California, San Diego, and the MIT Plasma Science and Fusion Center.
The researchers used extreme-scale plasma turbulence code XGC to perform the simulation. The massively parallel simulation, which revealed the physics behind the transition, ran for three days and took 90 percent of the capacity of Titan at the Oak Ridge Leadership Computing Facility (OLCF). Titan is the most powerful supercomputer for open science in the United States and is capable of performing up to 27 million billion (1015) operations per second.
For more information, see the PPPL news.