World’s largest tokamak gets advanced tool to measure fusion heat

The JT-60SA fusion facility in Naka, Japan, has reached a major milestone with the installation of the Edge Thomson Scattering (TS) diagnostics system, complementing the already developed core TS system. Thomson Scattering is a vital diagnostic technique that uses laser light scattered by plasma electrons to measure electron temperature and density, key parameters for understanding and controlling fusion reactions. The combined core and edge TS systems provide comprehensive, high-resolution coverage of the plasma cross-section, with the core system measuring 46 points from 2.6 m to 3.73 m radius and the edge system covering 49 points from 3.7 m to 4.17 m radius. The fine spatial resolution, narrowing to 5.5 mm at the plasma edge, enables detailed analysis of critical plasma features such as the pedestal profiles. Designed for high operational performance, the core TS system operates at 50 Hz and the edge system at 100 Hz, allowing rapid data acquisition essential for plasma stability and control