Introduction to Diagnostics

The diagnostic techniques developed in high-temperature plasma physics cover an extremely broad range of underlying physical processes and technical implementations. In this paper a short survey will be given by categorising the wide variety of methods into electrotechnical (mainly magnetic) measurements, passive observations of particle and photon fluxes emerging from the plasma, and active explorations by means of photon and particle beam probes. In addition, some general considerations concerning redundancy and interconnection of various techniques as well as data acquisition and analysis will be briefly discussed.