Radiated Power Measurements on the ST40 Tokamak

Measuring the total radiated power of magnetically confined plasmas is crucial for understanding impurity composition and transport. Similarly, as a significant fraction of the power exhaust, its measurement is necessary for confinement studies. To support these investigations on ST40, a number of 1D, pinhole cameras view the emission from the plasma tangentially and poloidally. The views are matched between multi-channel arrays of resistive foil bolometers (total of 28 lines of sight) and AXUV photodiodes (total of 32 lines of sight), with emissivity profiles provided every 10 ms (bolometers) and every 5 ms (photodiodes). Here, the consistency of the total radiated power measurements across experimental campaigns is evaluated and compared to the bremsstrahlung and soft X-ray emission. The analysis highlights variations in the radiated power profiles for L- and H-mode plasmas, and the impact of mid-Z, impurity gas seeding.