ISSN:
1432-0630
Keywords:
PACS: 52.50.Jm; 52.70.Ds; 52.75.Rx
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract. A Langmuir probe was used as a diagnostic of the temporally evolving electron number densities within a low-temperature laser-ablated titanium plasma expanding in vacuum. Measurements were made following ablation by a KrF excimer laser (248 nm, τ=30 ns) and a frequency-doubled Nd:YAG laser (532 nm, τ=7.5 ns) for laser power densities between 85 MW cm-2 and 1130 MW cm-2 on target. Electron number density data were obtained from the saturation electron current region of the probe (I/V) characteristic. Peak electron number densities in the range 1.5×1010 cm-3 to 1.5×1013 cm-3 were measured, at a distance of 5 cm along the target normal, for the laser power range investigated. Above ablation threshold the temporally integrated electron flux increased linearly with incident power density for both ablation wavelengths. The ablation thresholds, in terms of peak power density within the laser spot on the target, were found to be 85±20 MW cm-2 for KrF ablation and 300±50 MW cm-2for 2ω YAG ablation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s003390051477
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