Key issues in diagnostics for burning plasma experiments

The development of diagnostics for a next step burning plasma device (BPX) will be a major challenge. A starting point is the development and justification of the requirements for the measurement of quantities for plasma control, machine protection, and physics evaluation. The design of diagnostic systems and components, to perform these measurements in a BPX, is complicated by the fact that they need to operate reliably for a long time in a very hostile environment. A range of radiation-induced effects may deteriorate the characteristics of electrical and optical components, and R&D programs are focused on finding suitable materials. This paper first addresses the measurement requirements and then focuses on a number of important R&D issues.