Quantitative Measurements of Electron Number Density and Threshold for Laser Induced Breakdown in Air

2015 ◽  
Author(s):  
Liu Su ◽  
Yue Wu ◽  
Jordan C. Sawyer ◽  
Zhili Zhang
Keyword(s):  
Electron Number Density ◽  
Number Density ◽  
Electron Number ◽  
Quantitative Measurements ◽  
Laser Induced Breakdown

Temperature and Electron Number Density of Liquid Jet Double-Pulse Laser Induced Breakdown Ca Plasma

2013 ◽  
Vol 33 (4) ◽  
pp. 0430004
Author(s):  
胡振华 Hu Zhenhua ◽  
张巧 Zhang Qiao ◽  
丁蕾 Ding Lei ◽  
王颖萍 Wang Yingping ◽  
郑海洋 Zheng Haiyang ◽  
...  
Keyword(s):  
Pulse Laser ◽  
Electron Number Density ◽  
Double Pulse ◽  
Liquid Jet ◽  
Number Density ◽  
Electron Number ◽  
Laser Induced Breakdown ◽  
Double Pulse Laser

scholarly journals Spatial confinement effects employed by metallic blocker and Ar gas pressures on laser-induced breakdown spectroscopy and surface modifications of laser-irradiated Mg

2017 ◽  
Vol 35 (2) ◽  
pp. 313-325 ◽  
Author(s):  
A. Hayat ◽  
S. Bashir ◽  
M. S. Rafique ◽  
R. Ahmed ◽  
M. Akram ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Electron Number Density ◽  
Number Density ◽  
Confinement Effects ◽  
Electron Number ◽  
Plasma Parameters ◽  
Spatial Confinement ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown ◽  
Ar Gas

AbstractSpatial confinement effects on plasma parameters and surface morphology of laser-ablated Mg are studied by introducing a metallic blocker as well as argon (Ar) gas at different pressures. Nd: YAG laser at various fluences ranging from 7 to 28 J/cm2 was employed to generate Mg plasma. Confinement effects offered by metallic blocker are investigated by placing the blocker at different distances of 6, 8, and 10 mm from the target surface; whereas spatial confinement offered by environmental gas is explored under four different pressures of 5, 10, 20, and 50 Torr. Laser-induced breakdown spectroscopy analysis revealed that both plasma parameters, that is, excitation temperature and electron number density initially are strongly dependent upon both pressures of environmental gases and distances of blockers. The maximum electron temperature of Mg plasma is achieved at Ar gas pressure of 20 Torr, whereas maximum electron number density is achieved at 50 Torr. It is also observed that spatial confinement offered by metallic blocker is responsible for the significant enhancement of both electron temperature and electron number density of Mg plasma. Maximum values of electron temperature and electron number density without blocker are 8335 K and 2.4 × 1016 cm−3, respectively, whereas these values are enhanced to 12,200 K and 4 × 1016 cm−3 in the presence of blocker. Physical mechanisms responsible for the enhancement of Mg plasma parameters are plasma compression, confinement and pronounced collisional excitations due to reflection of shock waves. Scanning electron microscope analysis was performed to explore the surface morphology of laser-ablated Mg. It reveals the formation of ripples and channels that become more distinct in the presence of blocker due to plasma confinement. The optimum combination of blocker distance, fluence and Ar pressure can identify the suitable conditions for defining the role of plasma parameters for surface structuring.

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