Plasma Diagnostics in View of ITER

The ITER environment imposes many challenges for the various diagnostic systems. At the one hand diagnostic functionalities are required that go well beyond those at present devices. This is because there is a need to actively control (the profiles of) multiple plasma parameters, implying that measurement systems should be accurate and reliable. At the other hand the application of diagnostics at ITER is strongly hampered by constraints arising from the relatively harsh environmental conditions that give rise to phenomena that are new to the diagnostic designs. The nuclear environment puts stringent demands on the engineering and robustness of diagnostics, while the long pulse lengths require high stability of all systems. This paper will present an overview of the diagnostics for ITER with an additional glance in the further future.