The Compact Advanced Tokamak (CAT) concept uses physics models to show that by carefully shaping the plasma and the distribution of current in the plasma, fusion plant operators can suppress turbulent eddies in the plasma. This would reduce heat loss and allow more efficient reactor operation. This advance could help achieve self-sustaining plasma and smaller, less expensive power plants.
In a conventional tokamak, the cross-section of the plasma is shaped like the letter D. Facing the straight part of the D on the inside side of the donut-shaped tokamak is called positive triangularity. New research suggests that reversing the plasma—negative triangularity–reduces how much the plasma interacts with the surfaces of the tokamak for reduced wear.
Creating an efficient fusion plasma in a tokamak requires a plasma with an extremely hot core but edges cool enough to protect the tokomak walls. Researchers at the DIII-D National Fusion Facility developed a solution that uses the active injection of gases to cool the edge coupled with enhanced core confinement.