Observation and evaluation of the alignment of Thomson scattering systems.

Concerning plasma diagnostics based on Thomson scattering (TS), precise adjustment and proper alignment is of great importance in order to provide reliable and accurate measurements. Any misalignment could result in an incorrectly determined plasma density or prevent the measurement with this type of diagnostic altogether. Suitable means of alignment monitoring should be integrated into each TS diagnostic system. Variations of commonly used methods are discussed in this article. Correlation of results from alignment control with performed measurements of vibrations on the COMPASS tokamak is presented. Various techniques of optimization of alignment monitoring are shown. The optimal technique, which could be accommodated during the construction of TS diagnostic systems in future fusion devices, is proposed.