Diagnosis of the surface morphology of laser-ablated materials using the weighted- DCT approach in laser speckle interferometry for application to plasma facing materials

Yuanbo LI (李元博); Hongbei WANG (王宏北); Xiaoqian CUI (崔晓倩); Shuhua LI (李树华); Dongye ZHAO (赵栋烨); Hongbin DING (丁洪斌)

doi:10.1088/2058-6272/ab277c

Plasma Science and Technology > 2019 > 21(9): 95601-095601. > DOI: 10.1088/2058-6272/ab277c

Yuanbo LI (李元博), Hongbei WANG (王宏北), Xiaoqian CUI (崔晓倩), Shuhua LI (李树华), Dongye ZHAO (赵栋烨), Hongbin DING (丁洪斌). Diagnosis of the surface morphology of laser-ablated materials using the weighted- DCT approach in laser speckle interferometry for application to plasma facing materials[J]. Plasma Science and Technology, 2019, 21(9): 95601-095601. DOI: 10.1088/2058-6272/ab277c

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Diagnosis of the surface morphology of laser-ablated materials using the weighted- DCT approach in laser speckle interferometry for application to plasma facing materials

¹ School of Physics and Optical Electronic Technology, Dalian University of Technology, Dalian 116024, People's Republic of China
² Advanced Energy Research Center, Shenzhen University, Shenzhen 518060, People's Republic of China
³ Forschungszentrum Jülich, Institut für Energie- und Klimaforschung-Plasmaphysik, Partner of the Trilateral Euregio Cluster (TEC), D-52425, Jülich, Germany

Funds: This work was supported by the National Key R&D Program of China (No. 2017YFE0301304) and National Natural Science Foundation of China (Nos. 11605023, 11805028, 11705020), China Postdoctoral Science Foundation (Nos. 2017T100172, 2016M591423), and the Fundamental Research Funds for the Central Universities (Nos. DUT17RC(4)53, DUT18LK38).

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Received Date: March 03, 2019
Revised Date: June 02, 2019
Accepted Date: June 05, 2019

Graphical Abstract

Abstract

Abstract

To implement on-line, real-time monitoring for the surface morphology of Plasma-Facing Materials (PFMs) in tokamak, we developed a Laser Speckle Interferometry measurement approach. A laser ablation method was used to simulate the erosion process during Plasma-Wall Interactions in a tokamak. In the present investigation, we evaluated the results of laser ablation morphology changes on the surface of Mo material reconstructed by four different approaches (Flood-fill, Quality-guided, Discrete Cosine Transform (DCT) and Weighted-DCT). The morphology results measured by the weighted-DCT approach are very close to the measurement results from confocal microscopy with an average error rate within 7%. It is verified that the weighted-DCT algorithm has high accuracy and can efficiently reduce the influence of noise pollution coming from laser ablation, which is used as a proxy for erosion from plasma wall interaction. Additionally, the CPU computer time has been shortened. This is of great significance for the real-time monitoring of PFMs’ morphology in the Experimental Advanced Superconducting Tokamak (EAST) in the future.
- tokamak,
- fusion,
- plasma-wall interactions,
- laser speckle interferometry,
- topographical reconstruction algorithms

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References (20)

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