Dynamics of the Optical Characteristics of Erosion Laser Flares of Metals Formed by Intense Nanosecond Laser Pulses Under Atmospheric Conditions

Possibility of applying a hydrodynamic model to describe the laser erosion of metals irradiated by high-intensity nanosecond pulses

“…To experimentally study the optical characteristics of laserproduced plasma (using the techniques of transverse laser probing [10,11] and laser-induced plasma spectroscopy [12]) in this work we employed a research complex, which comprised the means for monitoring the dynamics of the spectral, spatial, and phase structures of laser-produced plasma plumes (LPPs) of metals with a high temporal resolution.…”

“…The investigations of Refs [11,12] showed that the peak of erosion plume glow for t = 20 ns (I ~ 10 9 W cm -2 ) is located at less than 1 mm from the target surface, while for pulses of similar intensity with t = 100 ns [10] at 1 - 2 mm (which is attributable to the higher energy density). This permits characterising the spatial scales of erosion plumes early in their nonstationary formation in atmospheric conditions.…”

“…The detonation of a metal macrolayer, which possesses considerable excess energy, has the effect that there appears an intensely glowing plasma-vapour plume at the surface plasma region with a short delay relative to the onset of laser irradiation (5 - 10 ns for a pulse of duration t = 20 ns [11] and 30 - 40 ns for t = 100 ns [10]). This plume rapidly expands into the ambient medium and interacts with the irradiating laser pulse [12].…”

Physics of Laser-Induced Plasma Streams Under Irradiation of Metals with Nanosecond Laser Radiation Pulses at Atmospheric Pressure

“…As noted in the previous section, irradiation of a metal with high-power nanosecond laser pulses leads to the formation in it of a macrolayer, whose thickness is determined by the penetration depth of the radiation and which has a considerable amount of excess energy. This leads to the fact that shortly after the beginning of the laser irradiation (with a delay of 5-10 ns for the 20-nanosecond pulse [45] and 30-40 ns for the 100-nanosecond pulse [46]), in the near-surface region of the target there appears a bright luminous vaporplasma formation expanding rapidly in the direction of the environment while interacting with the acting laser pulse [48]. Since the processes of vapor outfl ow into a vacuum and into a gas atmosphere differ radically, the spatial, energy, spectral, and other characteristics of erosion torches will differ considerably even under comparable irradiation conditions [15,16,49,50].…”

“…Experimental studies of the gas-dynamic processes taking place in the case of laser erosion of metals by nanosecond pulses in the presence of rarefi ed gases [24,49] and at atmospheric pressure [25,26,45,46,48,52] showed a qualitative difference between the processes of initiation of a vapor-plasma formation in air and its interaction with the incident radiation as compared to the case of initiation of a vapor-plasma formation in vacuum [53][54][55][56]. In [45,46,48], it was shown Fig. 4.…”