Thomson scattering diagnostic at the gas dynamic trap

TL;DR

This paper describes the implementation and initial results of a Thomson scattering diagnostic at the GDT, providing accurate radial profiles of plasma electron temperature and density using a Nd:YAG laser and multiple sightlines.

Contribution

It introduces a multi-line-of-sight Thomson scattering diagnostic at GDT and reports initial successful measurements of plasma profiles with high accuracy.

Findings

Radial profiles of T_e and n_e obtained with few percent accuracy.

Diagnostic operates effectively at T_e ≥ 20 eV and n_e ≥ 10^{19} m^{-3}.

Initial results demonstrate the diagnostic's capability for plasma parameter measurements.

Abstract

The incoherent Thomson scattering diagnostic with multiple line of sight is installed at the gas dynamic trap (GDT) for measurements of radial profiles of the plasma electron temperature and density. The diagnostic is based on a Nd:YAG laser with the wavelength of $1064 nm$. Its collecting lens uses $90^\circ$ scattering geometry having eleven lines of sight in total. At the current stage, six of them are equipped with interference filter spectrometers. Results of the initial operation within a month-long experimental campaign at GDT show that radial profiles are delivered with the accuracy of few percent for $T_e \geqslant 20 eV$ and $n_e \geqslant 10^{19} m^{-3}$. The next planned boost of the diagnostic performance is upgrade with the pulse burst laser to study a fast dynamics of plasma parameters in every GDT shot.