Ray-tracing analysis for combined Doppler backscattering and cross-polarization scattering diagnostic on the HL-2M tokamak.

To measure plasma density and magnetic fluctuations on the HL-2M tokamak simultaneously, a new diagnostic system combining Doppler backscattering (DBS) and cross-polarization scattering (CPS) is under development. It is essential to understand the propagation of injected and scattered rays to support the electronic/quasi-optical design and subsequent interpretation of the detected signals of the multi-channel DBS/CPS measurements. Thus, ray-tracing analysis with the axisymmetric ray-tracing code BORAY has been performed to estimate the scattering location and wavenumbers of the density and magnetic fluctuations.

Manufacture of TiO nanoparticles with high preparation efficiency and photocatalytic performance by controlling the parameters of pulsed laser ablation in liquid.

This study proposes a method to improve the production efficiency and photocatalytic performance of TiO2 nanoparticles using the pulsed laser ablation in liquid (PLAL) method to optimise preparation parameters. In this study, the variation of particle size, morphology, preparation, and catalytic efficiency due to the increase in the number of pulses is studied. The mechanism of particle morphology change is analysed using thermodynamic simulation.

Rapid photodegradation of methylene blue by laser-induced plasma.

A new strategy was established for the degradation of wastewater-based organic pollutants. Laser-induced plasma (LIP) was used as an alternative UV light source to realise rapid photodegradation of methylene blue (MB), an organic pollutant. A conventional 1064 nm Nd:YAG laser was used for plasma excitation to degrade MB solutions.

Recent advances in high- experiments and magnetohydrodynamic instabilities with hybrid scenarios in the HL-2A Tokamak.

Over the past several years, high- experiments have been carried out on HL-2A. The high- is realized using double transport barriers (DTBs) with hybrid scenarios. A stationary high- ( ) scenario was obtained by pure neutral-beam injection (NBI) heating.

Influences of fusion neutrons on Compton suppressed γ-spectrum analyses at the HL-2A tokamak.

The newly-built Compton suppression system at the HL-2A tokamak works in a harsh fusion neutron field especially when the second neutral beam injection system is put into application. The present paper performed Geant4 simulations to study the influences of fusion neutrons on Compton suppressed γ-spectrum analyses. The simulation data show that the influence of fusion neutrons on suppressed γ-spectrum shape is limited, while the influence on detection efficiencies is considerable.

A multiplexer-based multi-channel microwave Doppler backward scattering reflectometer on the HL-2A tokamak.

The Doppler backward scattering (DBS) reflectometer has become a well-established and versatile diagnostic technique for the measurement of density fluctuations and flows in magnetically confined fusion experiments. In this work, a novel multiple fixed-frequency array source with a multiplexer technique is developed and applied in the multi-channel DBS system. The details of the system design and laboratory tests are presented.

Development of high-speed vacuum ultraviolet spectroscopy using a modified Seya-Namioka monochromator and channel electron multiplier detector in the HL-2A tokamak.

A high-speed vacuum ultraviolet monochromator is developed for the HL-2A tokamak through the introduction of a novel channel electron multiplier in a modified Seya-Namioka spectrometer. A good signal to noise ratio of above 2000 is attained in the development phase of the system with typical operating parameters for observing routine HL-2A plasmas. The wavelength calibration is performed using characteristic line emissions from a hollow cathode light source with helium and argon discharges.

A novel multi-channel quadrature Doppler backward scattering reflectometer on the HL-2A tokamak.

A novel 16-channel fixed frequency Doppler backward scattering (DBS) reflectometer system has been developed on the HL-2A tokamak. This system is based on the filter-based feedback loop microwave source (FFLMS) technique, which has lower phase noise and lower power variation compared with present tunable frequency generation and comb frequency array generation techniques [J. C.

Development of microwave imaging reflectometry on the HL-2A tokamak.

A microwave imaging reflectometry system has been developed to visualize the density fluctuations on the HL-2A tokamak. This system is characterized by a quasi-optical system, a four frequency microwave transmitter, and a microwave quadrature receiver system with a 3D adjustable U-shaped horn antenna array, that generate 8 (poloidal) × 4 (radial) × 2 (toroidal) = 64 channel images of density fluctuations. Simulations and laboratory tests of the optical system have been conducted.