Characterization and calibration of the Thomson scattering diagnostic suite for the C-2W field-reversed configuration experiment.

Abstract

The new C-2W Thomson scattering (TS) diagnostic consists of two individual subsystems for monitoring electron temperature (Te) and density (ne): one system in the central region is currently operational, and the second system is being commissioned to monitor the open field line region. Validating the performance of the TS's custom designed system components and unique calibration of the detection system and diagnostic as a whole is crucial to obtaining high precision Te and ne profiles of C-2W's plasma. The major components include a diode-pumped Nd:YAG laser which produces 35 pulses at up to 20 kHz, uniquely designed collection lenses with a fast numerical aperture, and uniquely designed polychromators with filters sets to optimize a Te ranging from 10 eV to 2 keV. This paper describes the design principles and techniques used to characterize the main components of the TS diagnostic on C-2W, as well as the results of Rayleigh scattering calibrations performed for the whole system response.