Laser-aided diagnostics of JT-60SA

JT-60SA is currently the world's largest superconducting tokamak. It accelerates the realization of fusion energy by supporting ITER exploitation and complementing it in addressing key physics and engineering issues for DEMO reactors. The main targets of JT-60SA are breakeven-equivalent high-temperature deuterium plasmas and high-βsteady-state plasmas. To achieve these goals, laser-aided diagnostics with high spatial resolution are essential for detailed physics studies. In Operation Phase 1, a tangential single-chord two-color CO2laser interferometer was installed. The data acquisition and processing system featured fringe-jump detection and real-time processing, enabling density feedback control. In the upcoming operational phases, a CO2laser polarimeter and Thomson scattering diagnostics will be implemented in Operation Phase 2, followed by the installation of phase-contrast imaging in Operation Phase 3. This paper summarizes the measurement results from the first operational phase and outlines the design and current status of the other three diagnostics.