Development of beam emission spectroscopy diagnostic on EAST

Abstract

Beam Emission Spectroscopy (BES) diagnostic based on Neutron Beam Injection (NBI) on the Experimental Advanced Superconducting Tokamak has been developed. This system consists of 16 × 8 channels which can diagnose the density fluctuation in a rectangular area of about 20 × 10 cm in the cross section, whose radial position is adjustable from the core to edge just by means of changing the angle of the rotation mirror. The spatial resolution is about 1-3 cm according to the diagnosed radial position. The temporal resolution is 1 μs. Space calibration of the diagnostic system is done based on the reversibility of the optical path. The NBI modulation experiment shows the success of BES development.

Optical design of the Lyman alpha based beam emission spectroscopy (LAB) diagnostic on the HL-2A tokamak

“…There are mainly two kinds of transmission optics for BES diagnostics. One is the lens group [11,12], and the other is the combination usage of a few light-collection lenses and fibers [3,13]. Unfortunately, this rich experience is not suitable for LAB development.…”

Simulation of neutral beam attenuation and its influence to beam emission spectroscopy diagnostic on HL-2A tokamak

“…Beam Emission Spectroscopy (BES) based on NBI (Neutral Beam Injection) is an optical diagnostic which has been developed to measure long wave-length (k θ ρ s < 1) density fluctuations and magnetohydrodynamic (MHD) instabilities in tokamak and stellarator plasmas [1][2][3][4][5]. With high spatial (1~2 cm) and temporal (~1 µs) resolutions, BES system contributes to the research of some important magnetically confined plasma physical topics, such as L-H mode (Low mode to High mode) transition, pedestal dynamics and quasi-coherent mode [6][7][8].…”