Development of a 2D spatial displacement estimation method for turbulence velocimetry of the gas puff imaging system on EAST

A gas puff imaging(GPI)diagnostic has been developed and operated on EAST since 2012,and the time-delay estimation(TDE)method is used to derive the propagation velocity of fluctuations from the two-dimensional GPI data.However,with the TDE method it is difficult to analyze the data with fast transient events,such as edge-localized mode(ELM).Consequently,a method called the spatial displacement estimation(SDE)algorithm is developed to estimate the turbulence velocity with high temporal resolution.Based on the SDE algorithm,we make some improvements,including an adaptive median filter and super-resolution technology.After the development of the algorithm,a straight-line movement and a curved-line movement are used to test the accuracy of the algorithm,and the calculated speed agrees well with preset speed.This SDE algorithm is applied to the EAST GPI data analysis,and the derived propagation velocity of turbulence is consistent with that from the TDE method,but with much higher temporal resolution.

Impact of resonant magnetic perturbation on blob motion and structure using a gas puff imaging diagnostic on the HL-2A tokamak

The impact of resonant magnetic perturbation(RMP)on blob motion and structure in the SOL of the HL-2A tokamak is studied using a gas puff imaging diagnostic.Ellipse fitting is applied to study the structure and motion of blobs quantitatively.The radial locations,amplitudes and scale sizes of blobs are obtained based on the fitted ellipse.Furthermore,based on the measurement of blob location,the radial and poloidal velocities of blobs are calculated.With the application of RMP,the edge poloidal shear flow is significantly weakened and the wave number spectrum changes from quasisymmetric to significantly up-down asymmetric.The application of RMP also causes the detected blob location to be much further into the far scrape-off layer(SOL)and increases the blob amplitude.Blob poloidal velocity in the SOL is slowed.Larger-size and longer-lifetime blobs are observed with RMP.With the application of RMP,stronger-amplitude and larger-size blobs are detected in the far SOL and they may cause a more serious erosion problem to the first wall.

Observation of blobs using a gas puff imaging diagnostic on the HL-2A tokamak

A gas puff imaging(GPI) diagnostic has been developed and applied to measure edge plasma turbulence on the HL-2A tokamak.The principle and experimental setup of GPI are described.GPI is applied to investigate blobs in the edge and scrape-off layer.Statistical characterizations of GPI line emission intensity are calculated, including the probability density functions(PDFs),skewness, and kurtosis of the intensity, which are found to be consistent with measurements by Langmuir probes.Besides, the track of blob motions is recorded by time sequence of individual frames.The characteristics of the original images and the relatively high-frequency(>10 kHz)/low-frequency(1–10 kHz) component images are illustrated.The observation of the blob’s structures and high-speed motions proves the success and high performance of the GPI diagnostic.

HL-2A Tokamak Gas Puff Imaging

Gas puff imaging （GPI） is one of the important diagnostics for the （ITPAC international tokamak physics activity ） and entering the ITPA IDD （ international diagnostics database ） . GPI is related to many investigations, for example, edge radiations, etc.

Development of Debris-free Laser Plasma Sources for EUV Lithography in CIOMP

We have been developing debris-free laser plasma sources for EUV lithography since 1996. Two types of debris-free sources, such as cryogenic target and gas-puff target laser plasma sources, were designed and built up in CIOMP. EUV radiation spectra of the sources with a variety of targets have been obtained by different ways.

Simulation analysis of environmental risk accident and management of high-sulfur gas field development in complex terrain

Environmental risk of high sulfur gas field exploitation has become one of the hot spots of environmental management studies.Severe gas H_(2)S blowout accidents in recent years have shown that poor understanding and estimates of the poisonous gas movement could lead to dangerous evacuation delays.It is important to evaluate the real concentration of H_(2)S,especially in complex terrain.Traditional experiential models are not valid in the case of rough terrain,especially in low-lying areas where the gas accumulates.This study,using high sulfur content gas field of Sichuan“Pu Guang gas field”as study object and adopting objective diagnosis of wind field of land following coordinate three dimensions,applied Lagrangian Puff Model and breaking up technique of puffs to simulate the H_(2)S diffusion condition of blowout accidents produced in the high sulfur content gas field of complex terrain area.The results showed that the H_(2)S distribution did not occur mainly in low wind direction,and due to the obstruction of the mountain’s body,it accumulated in front of mountain on produced turn over,flowed around submitted jumping type distribution.The mountain waist near the hilltop and low hollow river valley site rapture points simulating contrast showed that the higher the rapture point,the better the diffusing condition of pollutant,the distribution of risk sensitive point decided piping rupture environmental risk size combining the H_(2)S diffusion result and residential area dispersing in the study area,synthetic judge located in the high rapture point environmental risk was smaller than the low hollow point,thus it was suggested to carryout laying of lining build of equal high line of higher terrain.According to simulation results,the environmental risk management measures aimed at putting down adverse effects were worked out.