Multiple Laser System For High-Resolution Thomson Scattering Diagnostics On The East Tokamak

A multiple laser system for high-resolution Thomson scattering diagnostics has been developed in ASIPP. The system includes laser controller, high-energy lasers, transfer optics, focusing lens, and beam alignment system. Each Nd:YAG laser can be fired for measuring the electron temperature and density profiles periodically at 10 Hz, and consequently, four lasers can be fired alternately for an average measurement frequency of 40 Hz. In order to measure transient events, they will be fired in rapid succession, and produce a burst of pulses. After about one month trial running on the superconducting EAST tokamak, the system was proven to be capable of working well with improved time resolution. The system setup and analysis are described in detail, as well as the measurement capability, spatial and temporal resolutions similar to 7 mm and tens kilohertz, respectively. So as to monitor and adjust the laser beam, two beam position sensitive detectors are installed in the 40-m beam path. Finally, the experimental results are presented.