Plasma Diagnostics in T-15MD Divertor: Tasks, Problems, and Implementation Possibilities

The article considers different methods of divertor plasma diagnostics planned for using in the T‑15MD tokamak. Technical problems arising during operation of optical systems in the divertor zone are discussed, including degradation of in-vessel optical elements. The main attention is paid to the conceptual design of the “Passive Spectroscopy in Divertor” diagnostic system. The optical system, including in-vessel mirrors, and methods for protecting its components from the negative effects of plasma are described in detail. Using synthetic diagnostics and numerical simulation methods, the possibility of solving the problem of tomographic reconstruction of the two-dimensional profile of plasma radiation in the T-15MD divertor is demonstrated. Based on the results presented, it was concluded that passive spectroscopy can be used for obtaining data on plasma parameters in the divertor with good spatial resolution, which will make it possible to study the physics of processes and monitor the operation of the T-15MD divertor, including the operation in detachment regime.