The dynamic behaviors and optical properties of a ZnO plasma plume produced by pulsed laser ablation using a Nd:YAG laser (wavelength: 532 nm, pulse width: 3 ns) were studied by fast photography using a commercial gated charge coupled device (CCD) camera linked with a delay circuit and by optical emission spectroscopy at various ...
NASA Astrophysics Data System (ADS)
The Zn-to-Cu ratio in brass was measured by laser ablation inductively coupled plasma atomic emission spectroscopy. The influence of laser beam properties (pulse width, wavelength, and power density) on fractional laser ablation was investigated. The behavior of the Zn/Cu ratio vs. laser power density shows that ...
Energy Citations Database
The effect of an artificially deposited liquid film on a laser-ablated metal surface at near-threshold laser fluences is presented. Experiments utilizing a Q-switched Nd:YAG laser (wavelength=1064 nm, full width at half maximum=6 ns) reveal that deposition of a liquid film results in substantial reduction of ablation threshold and ...
A time resolved imaging study of pulsed laser ablated Fe and Al plasma plumes with specific interest in the splitting of plumes into the slow and fast moving components as they expand through the background argon gas at different pressures is reported. The material ablation was achieved using a Q-switched Nd:YAG (yttrium aluminum ...
The effects of energy and pulse duration in laser ablation experiments have been investigated in the case of copper based alloys. Experiments were carried out near 530nm by using two laser sources with different widths (8 ns and 250 fs). The craters generated by lasers were examined and their characteristics were related to different mechanisms involved in ...
... Descriptors : *ABLATION, *ATMOSPHERE ENTRY, *PLASMA ... AND MAGNETOHYDRODYNAMICS RADIOFREQUENCY WAVE PROPAGATION. ...
DTIC Science & Technology
Pb-doped ZnO nanostructures were prepared using millisecond pulse-width laser ablation. Nanoparticle chains formed when the laser ablation was performed in air or on a pure Zn target, and when Ar flow was introduced it could be used to mediate the nucleation and growth of crystalline nanorods from a composite Zn/Pb target. Based on the ...
... Title : Experimental Scaling Laws for Mass-Ablation Rate, Ablation Pressure in Planar Laser-Produced Plasmas With Laser Intensity, Laser ...
... of the propellant ablation under plasma effect based on ... Knudsen layer and the hydrodynamic layer. ... indicate that the ablated mass increases with ...
... LASER BEAMS, *NUCLEAR FUSION, ABLATION, PLASMAS ... LASERS, MOMENTUM TRANSFER, PLASMA DIAGNOSTICS, FOILS(MATERIALS ...
... Accession Number : ADA306854. Title : Comparative Evaluation of Ablating Materials in ARC Plasma Jets. Corporate Author ...
The experimental study of absorption in silicon in infrared and visible spectral ranges, where the photon energy is less or more than the bandgap width, is performed by means of the ultrafast interferometry technique. The exactly solvable model in the electromagnetic of heterogeneous lossy plasma layer was developed. The density of carriers, their ...
The self-organized formation of ripples in the direction parallel to the groove during the femtosecond laser machining of microgrooves on aluminum nitride ceramic at laser fluences much higher than the single-pulse ablation threshold is reported. These parallel ripples are notably different from the commonly observed polarization-perpendicular ripples and are produced in ...
In this paper, we showed the performance of a propulsion system in space by ablation plasma produced by pulsed ion beam and its controllability. First, the fundamental study of flyer acceleration with ablation plasma produced by irradiation of an intense pulse ion beam was explained numerically. Here, we used a ...
... are pointed out. electrothermal guns, plasma discharge, plasma devices, plasma jets. Descriptors : *PLASMA DEVICES ...
... Title : FORMULAS FOR ESTIMATING WIDTHS OF SPECTRAL LINES EMITTED FROM PLASMAS AND THEIR LIMITS OF VALIDITY. ...
Pulsed laser generated Fe plasma plumes have been studied near the target surface using time-resolved imaging. A fast gated intensified CCD camera is used to capture the images with a gate width of 2 ns. The plasma plumes were generated using a Q-switched Nd-YAG laser at 1064 nm with a fluence of �2 kJ/cm2. The expansion studies were ...
Laser ablation of porous silicon as a function of laser wavelength and width of silicon nanowires was studied in our experiments. The time-resolved evolution of the cloud of the porous silicon particles produced by laser ablation is studied in situ by the analysis of the kinetics of photoluminescence signal. The laser ...
A method for smoothing ablation pressure nonuniformities during heating of laser fusion targets is described which utilises an extra laser pulse preceding the main pulse. Theoretical and experimental data are presented on heating of thin (3-10 ?m) foils (simulating the target shell) by a spatially nonuniform laser beam. In the experiments, the laser pulse ...
Velocity distribution, pulse width dependence studies, and two-pulse correlation measurements have been used to study the possibility of the occurrence of ultrafast electronic and thermal ablation processes in Au exposed to ultrashort laser pulses in the femtosecond to picosecond time domain. Three distinct different velocity groups (5.5, 1.5, and 0.25 eV) ...
... Accession Number : ADA536231. Title : Spectroscopy Measurements on Ablation Testing in High Enthalpy Plasma Flows. ...
... ABLATIVE MATERIALS, *SPACE PROPULSION, SYMPOSIA, VACUUM, KNUDSEN NUMBER, MICROPULSATIONS, PLASMA ENGINES ...
... Descriptors : *ABLATION, *ACCELERATION, *LASER BEAMS, *FUSION( MELTING), HEAT TRANSFER, PLASMAS(PHYSICS), HIGH VELOCITY ...
... levels of radio frequency and microwave ... Descriptors : *ABLATION, *CARBON, *EMISSION ... PRODUCTION, PULSES, RADIOFREQUENCY, SIDES ...
... follows: The Grantee will investigate A.) Ablation of viscous polymers-- Liquid fuels ... measurements on the ablation of viscous polymer solutions will ...
... Descriptors : *THRUSTERS, ABLATION, REPRINTS, HIGH PRESSURE, RADIATION ABSORPTION, PLASMA ENGINES, BOUNDARY LAYER ...
Impacts of pellets injected from the low-field side (LFS) on plasma in ITER are investigated using the 1.5D BALDUR integrated predictive modeling code. In these simulations, the pellet ablation is described using the neutral gas shielding (NGS) model. The pellet ablation model is coupled with the plasma core ...
... the ablation front using a discontinuity model identical ... corresponds to the ablative pressure slowly decreasing from ... absorption in the plasma corona ...
Efforts are underway to automate the operation of a railgun hydrogen pellet injector for fusion reactor refueling. A plasma armature is employed to avoid the friction produced by a sliding metal armature and, in particular, to prevent high-Z impurities from entering the tokamak. High currents are used to achieve high accelerations, resulting in high plasma ...
Space charge effects, and the matrix interferences they cause, are problems in inductively coupled plasma mass spectrometry (ICPMS). It has previously been observed that these deleterious space charge effects are not significantly present in sector-field instruments, a fact that has been attributed, but not demonstrated, to the high accelerating potentials they commonly ...
... Single- and Double-Pulse Laser Ablation ... Optical emission characteristics of carbon plasma produced by single- and double-pulse laser ablation ...
... Title : Nonuniformities in Laser-Ablated Plasma. ... Calculations indicate that this may be due to thermal self-focusing of hot spots in the laser. ...
... 4. TITLE AND SUBTITLE ABLATION AND PLASMA FORMATION DURING DIRECTED ENERGY TESTING 5a. CONTRACT NUMBER 5b. ...
... Accession Number : ADA498298. Title : Ablation and Plasma Formation During Directed Energy Testing. Descriptive Note : Final technical rept. ...
Pulsed laser ablation (wavelength 532 nm; fluence 18 J/cm2; pulse width 7 ns; repetition rate 10 Hz) of highly oriented pyrolytic graphite was conducted in adamantane-dissolved supercritical CO2 with and without cyclohexane as a cosolvent. Micro-Raman spectroscopy of the products revealed the presence of hydrocarbons possessing sp3-hybridized carbons ...
In order to investigate the laser ablation propulsion property of different materials in atmosphere, experiments are conducted, with a Nd:YAG passive Q-switch solid laser (single pulse energy 66mJ, pulse width 70ns) as energy source, black rubber, gray PVC, brass and SiC as testing materials. As results, the momentum coupling coefficients of the measured ...
Laser ignition condition was studied for a new reaction control system using green propellant of GH2/GO2 by the use of laser-produced ablation plasma. Dependence of the laser pulse width on the minimum ignition laser energy was measured experimentally. Temporal behavior of the laser pulse gave an explanation of the dependence in 10 to ...
Particle size effects and elemental fractionation in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) are investigated with nanosecond and femtosecond laser ablation, differential mobility analysis, and magnetic sector ICP-MS. Laser pulse width was found to have a significant influence on the ...
The 355 nm laser pulse from THG (Third Harmonic Generation) of a Qswitched Nd3+ : YAG laser was used to ablate silicon mounted in air. The time-and space-resolved optical emission spectra were measured for different pulse energy in the wavelength range of 380-420 nm, the emission spectra of N+ was found for impact ionization of air near target surface on the early stage of ...
PubMed
Theories published on pellet ablation phenomena are reviewed. Some inconsistencies are shown to exist in some of the studies available. Models are developed and estimates are given for pellet ablation rates in hot plasmas with and without magnetic fields ...
National Technical Information Service (NTIS)
An improved model for CO{sub 2} laser ablation impulse in polyoxymethylene and similar polymers is presented that describes the transition effects from the onset of vaporization to the plasma regime in a continuous fashion. Several predictions are made for ablation behavior.
In the present work, we have reviewed and compared our experimental and theoretical Au II Stark widths. The interest in Au II resides not only on the knowledge of its atomic structure, or to check the adequacy of theoretical models, but also on its astrophysical importance because its lines are present in spectra of chemically peculiar stars.The plasma ...
... COMPUTER PROGRAMMING, RADIOFREQUENCY PULSES, INSTRUMENTATION, ABLATION, MICROWAVES, ELECTROMAGNETIC ...
... Title : EFFECTS OF POROSITY AND STRUCTURE OF GRAPHITE MATERIALS ON ABLATION IN ARC GENERATED PLASMAS,. ...
... of the ambient gases and ablation of the heat ... PLASMA PHYSICS AND MAGNETOHYDRODYNAMICS RADIOFREQUENCY WAVE PROPAGATION ...
... MICROWAVE COMMUNICATIONS, HALOGENS, ABLATION, ELECTRICAL IMPEDANCE ... ELECTRONIC EQUIPMENT RADIOFREQUENCY WAVE ...
... power dissipation in the plasma. ... Descriptors : *GUNS, VELOCITY, ABLATION, MAGNETIC ... RESISTANCE, INJECTORS, GUN MUZZLES, BORES ...
... an electrothermal chemical gun model include ... into the plasma-propellant interaction ... ELECTROTHERMAL CHEMICAL GUNS, ABLATION, MODELS ...
... Descriptors : *INTERACTIONS, *LASER BEAMS, *FOILS(MATERIALS ... Subject Categories : LASERS AND MASERS PLASMA PHYSICS AND ...
The structure and expansion characteristics of the plasma plume produced by laser ablation of a bulk tin target in vacuum have been investigated. A Q-switched Nd: YAG laser with 1064 nm wavelength, 5 ns pulse width, and the order of 10^11 W/cm^2 power density was employed to create ablation ...
A Nd:YAG laser, 9 ns pulse width, 30 Hz repetition rate, a maximum pulse density of 1010 W/cm2 and an iodine laser, 400 ps pulse, operating in single pulse width with a maximum power density of 1016 W/cm2, are employed to produce pulsed plasmas in vacuum. A comparison of the results obtained for the ablation of ...
Laboratory experiments to study collisionless shock generation in counter-streaming plasmas have been investigated using Gekko XII HIPER laser system (352 nm (3?), 500 ps, �100 J / beam, one or four beams, < 10^15 W/cm^2) at ILE. Two types of double-plane targets, Jet and Ablation types were used. In the Jet (Ablation) type, 10 ?m ...
Pellet ablation rates computed with the help of different ablation models are compared. For investigating the response of the plasma to the injected pellet, the ablation models are combined with a multiregime tokamak transport code. The results indicate that the ionization dynamics of the ...
The Stark broadening parameters of six lines of Zn II (4 measured for the first time) have been measured in a plasma produced by ablation of a Cd-Zn alloy with a Nd:YAG laser. The broadening parameters were obtained in molecular Argon at 6 Torr. A Boltzmann plot was used to obtain the plasma temperature and published values of the ...
... I. ablated materials consisting of ions and excited species ir- ... tween different figures. The wavelength indicator on the ialned from such profiles. ...
... MODELS, *STEADY STATE, *LASER TARGET INTERACTIONS, VELOCITY, ABLATION ... PLASMAS(PHYSICS), LASERS, LASER BEAMS, MASS ...
... Ablation losses of aluminum, polyethylene, phenolic, and grease, caused by impacting high-speed neon from a coaxial plasma gun were measured ...
The characteristics of ablation plasma from planar targets, driven by long Nd:glass laser pulses (4 nsec,
... Accession Number : ADD460302. Title : Adequacy Of Metal Ablation Process With Laser Radiation And A Shock-Compressed Plasma. ...
Ablative overlays were evaluated via a plasma-arc simulation of the ascent pulse on the leading edge
NASA Technical Reports Server (NTRS)
Optical near-field ablation-induced plasma characteristics David J. Hwang and Costas P December 2006 The physics of optical near-field based laser ablation plasmas is studied. A Cr thin metal film is ablated using visible nanosecond laser pulses coupled through an optical near-field fiber probe
E-print Network
Experimental evidence supporting the importance of ablation in plasma armature railguns is presented. Experiments conducted using the HYVAX and MIDI-2 railguns are described. Several indirect effects of ablation are identified from the experimental results. An improved ablation model of plasma ...
The purpose of this paper is to present a model for ablation due to a plasma flash in cylindrical symmetry. The model of ablation speed of the coaxial material is based on the integral method of the heat equation which basically involves the idea of a thermal layer. It is first shown that an important step in the process is the heating ...
The experiment of Bauer, et al. (1982) is analyzed by considering wall ablation and viscous drag in the plasma. Plasma characteristics are evaluated through a simple fluid-mechanical analysis considering only wall ablation. By equating the energy dissipated in the plasma with the radiation heat ...
Experimental evidence of the appearance of a proper periodic dynamics in a plasma plume created by pulsed laser ablation is considered as a hint for the presence of a self-organization scenario that explains similar phenomena observed in plasma diodes.
The effect of additional laser irradiation on the optical emission of laser ablated carbon plasma have been examined to define plasma conditions for the controlled synthesis of carbon structures.
... 29 22 Plasma Arc Tests 31 23 Plasma Arc Ablation Rutes at 50 Btu/ft 2-sec 33 23 Plasma Arc Ablation Rates at 50 Btu/ft2-sec 33 ...
Surface ablation of a dielectric material (fused silica) by single femtosecond pulses is studied as a function of pulse duration (7-450 fs) and applied fluence (F thablation ...
Pulsed laser ablation is a process in which an intense laser pulse interacts with the matter producing plasma. The present work describes the theoretical work being conducted in the past for the pulsed laser ablation phenomenon. It incorporates the theoretical models being proposed by various researchers around the globe for pulsed ...
... Descriptors : *PLASMAS(PHYSICS), *LASER BEAMS, ABLATION ... Subject Categories : LASERS AND MASERS PLASMA PHYSICS AND ...
Extreme ultraviolet (EUV) emission from discharge produced plasma with the coaxial injection of fuel vapor (tin and lithium) produced by laser ablation is experimentally studied. Multiple plasma pinches preceding a strong and long recombination radiation of EUV are observed in the first half cycle of a sinusoidal discharge current. Due ...
Soft metal gaskets (indium and silver) were used to reduce contact resistance between the wire and the electrode in an aluminum wire Z pinch by more than an order of magnitude over the best weighted contact case. Clamping a gasket over a Z-pinch wire compresses the wire to the electrode with a greater normal force than possible with wire weights. Average contact resistance was reduced from the ...
Nominal predicted plasma conditions in a compact ignition tokamak are illustrated by transport simulations using experimentally calibrated plasma transport models. The range of uncertainty in these predictions is explored by using various models which have given almost equally good fits to experimental data. Using a transport model which best fits the ...
A TEA CO2 laser (350 mJ 1.5 J, 10.6 ?m, 200 ns, 10 Hz) was focused onto a metal sub-target under He as host gas at 1 atmospheric pressure with a small amount of impurity gas, such as water and ethanol vapors. It was found that the TEA CO2 laser with the help of the metal sub-target is favorable for generating a strong, large volume helium gas breakdown plasma at 1 atmospheric ...
In femtosecond laser ablation the plume has two components: a faster-moving plasma part and a slower nanoparticle plume which contains most of the ablated material. This paper describes the results of experiments to comprehensively characterize the plume in laser ablation of Ni with {approx_equal}300 fs pulses at ...
In femtosecond laser ablation the plume has two components: a faster-moving plasma part and a slower nanoparticle plume which contains most of the ablated material. This paper describes the results of experiments to comprehensively characterize the plume in laser ablation of Ni with ~300 fs pulses at 527 nm. Both ...
... THICKNESS ON PROPERTIES OF THE PLASMA DISPLAY CELL,. ... design of Plasma Display Cells it is ... related to its physical dimensions, and can ...
Two dynamics modes, named short ablation mode and long ablation mode, are observed in implosion experiments of planar wire array Z pinch on �QiangGuang-I� facility utilizing an optical streak camera. The long ablation mode has a lagged trajectory compared with the short ablation mode. For shot 10035 in a short ...
The ablation-induced plasma physics at reduced ablation crater dimensions is experimentally investigated. Frequency doubled femtosecond laser pulses are tightly focused through objective lenses onto a Cr thin film coated on quartz wafer in order to obtain ablation craters of submicron lateral dimensions. Side-view ...
... The desired crystalline quality was a full-width, half-maximum value of the (002) peak < 0.120 (432 arc seconds) and the full-width, half-maximum ...
The ablative formation of deep channels in steel by femtosecond and picosecond laser pulses is studied. A significant screening of the incident energy inside deep channels is found to occur due to the air breakdown at ablated microparticles. The breakdown thresholds and the microparticle precipitation times are estimated. This kind of ...
Plasma quenching efficiency by ablated vapor of polymers containing nitrogen atom was numerically investigated for the inductively coupled thermal plasma technique. Polyamide66 (PA66), which contains nitrogen atoms, was used for polymer materials, and it is injected into Ar thermal plasma in the numerical ...
Laser ablation particle plume compositions are characterized using inductively coupled plasma mass spectrometry (ICP/MS). This study evaluates the mass response characteristics peculiar to ICP/MS detection as a function of laser fluence and frequency. Eva...
Endobronchial hamartoma is a rare benign tumour of the lung that may present with bronchial obstruction. We present a case of endobronchial hamartoma that was resected and ablated with electrocautery and argon plasma coagulation by fiberoptic bronchoscopy. PMID:18610683
The neutral gas shielding model and neutral-gas-plasma shielding model are analyzed qualitatively. The main physical processes that govern the formation of the shielding gas cloud and, consequently, the ablation rate are considered. For the neutral gas shielding model, simple formulas relating the ablation rate and cloud parameters to ...
The neutral gas shielding model for ablation of frozen hydrogenic pellets is extended to include the effects of an initial Maxwelliam distribution of incident electron energies; a cold plasma shield outside the neutral shield and extended along the magnet...
A plasma disruption within a fusion device the size of INTOR can create extensive first wall surface ablation. This paper discusses various first wall ablation models proposed by INTOR participants for the Phase I Design Study, particularly the nonequilib...
The NASA-Lewis computer program for the calculation of complex chemical equilibrium compositions (CEA) is proposed as a means of characterizing the compositions of plasmas generated via an ablating-capillary arc. Results obtained with CEA are compared to ...
The anode ablation rate is investigated as a function of anode diameter for a carbon nanotube arc plasma. It is found that anomalously high ablation occurs for small anode diameters. This result is explained by the formation of a positive anode sheath. Th...
Measurements on the interaction between solid hydrogen pellets and rotating plasmas are reported. The investigations were carried out because of the possibility of refuelling fusion reactors by the injection of pellets. The ablation rate found is higher than expected on the basis of a theory of a shielding neutral gas layer.
A pulse laser of ultraviolet region was used to form the flow path and so on. Numbers of heat-hardening resin-films and fluoro resins were piled up a soda glass. A laser fabricated a part of the channel at the each film every lamination, and then 3-D structure micro-channel was fabricated. The channel sizes are widths of 10-400?m and depths of 30-90?m. Moreover through holes ...
... the thermal properties of reinforced-plastic laminates at high ... Descriptors : *ABLATION, *REINFORCED PLASTICS, DENSITY, PLASMAS(PHYSICS ...
... for electromagnetic window material and air ... produced by ablating heat-shield materials. ... VEHICLES, ELECTROMAGNETIC RADIATION), (*WAVE ...
... Title : Experimental Study of Laser and Wavelength Dependences of Laser-Plasma Coupling, Transport, and Ablation Processes in Planar Gold ...
... reentry (plasma sheath including ablation effects) conditions at high ... SHEATHS), ATMOSPHERE ENTRY, RADIOFREQUENCY POWER, ANTENNA ...
A Green's function method is developed for the calculation of the line shape of the radiation from an atom in a plasma. It is shown that the width of the line is proportional to the imaginary part of the reciprocal of the dielectric function of the plasma...
We performed a retrospective three-dimensional ultrasound evaluation of the ovarian features in ten women with no previous ovarian surgery who benefited from ablation by plasma energy for unilateral endometriomas greater than to 30 mm in diameter. Values of ovarian volume and antral follicle count in operated ovaries were decreased by an average 12% and ...
-element fractionation in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis is one is close to 1. Since laser ablation inductively coupled plasma mass spectro- metry (LA-ICP-MS) was �rst) are commonly used as an internal standard for in situ multi-element LA-ICP-MS analysis. The ...
with experiment. The calculation of the AZ-PPT-3 performance for the case of high pulse energy is shown in Fig.81 AIAA �2001-3898 Performance Study of the Ablative Z-pinch Pulsed Plasma Thruster Michael Keidar, and Teflon ablation. Mechanisms of energy transfer from the plasma column to the propellant include ...
The influence of pulsed laser ablation of an aluminum target on the nitrogen plasma produced by electron cyclotron resonance (ECR) microwave discharge has been studied by optical emission spectroscopy (OES) with time and space resolution. The continuous wave (CW) feature of the optical emissions from the ECR nitrogen plasma turns to ...
This project involved a systematic study to apply newly discovered isotopic enrichment effects in laser ablation plumes to the fabrication of isotopically engineered thin films, superlattices, and nanostructures. The approach to this program involved using ultrafast lasers as a method for generating ablated plasmas that have ...
Near the pusher/fuel interface in the NIF indirect drive ignition capsule, the cold dense fuel can reach higher density than the material accelerating it. Unlike the outer surface where ablative stabilization is important, Rayleigh-Taylor (R-T) growth at this interface is stabilized only by the density gradient, plasma viscosity and mass diffusion. Highly ...
... with the plasma-jet for sprayed ceramic coatings ... the results of arc-plasma-jet tests ... RESISTANT METALS, ABLATION, SPRAYS, OXIDATION, TEST ...
Flare Plasma Heating. Little or no impulsive non-thermal component. In thick target model, non-thermal electrons heat and ablate the plasma ...
NASA Website
... Themicro-laser plasma thruster (uLPT) discussed here ... by focusing the laser through a ... ION DENSITY, *DIODE LASERS, VELOCITY, ABLATION ...
... Diagnostic measurements included magnetic flux density using small coil probes, current distribution using a Rogowski coil plasma front location ...
... Accession Number : ADP015032. Title : Optical Emission Characteristics of Carbon Plasma Produced by Single- and Double-Pulse Laser Ablation. ...
... of a Cheng type coaxial gun have been ... METAL PLATES, *PLASMA JETS, ABLATION ... CURRENT, ELECTRON GUNS, PERFORATION, HIGH ...
... The model predicts the existence of two steady-state regimes of plasma pressure for ablative discharge operation at a given plasma temperature. ...
The Eulerian/Lagrangian dynamics in the narrow wake field of the dusty plasma bubble is explored by directly tracking dust motion at the microscopic level. The bubble is induced by the focused laser pulse ablation in three-dimensional quiescent dusty plasma liquids operated in the pressure higher than the critical pressure for the ...
The Stark broadening parameters of 17 lines of Ni II have been measured in a plasma produced by ablation of an Al-Ni alloy with a Nd:YAG laser. The broadening parameters were obtained with the target placed in molecular argon at 6 Torr, which provides appropriate measurement conditions. A Boltzmann plot was used to obtain the plasma ...
The Stark broadening parameters of six lines of ZnII (four measured for the first time) have been experimentally determined in a plasma produced by ablation of a Cd-Zn alloy with a Nd:YAG laser and a Zn content under 10%. The broadening parameters were obtained with the target placed in molecular argon at 6 Torr, which provides appropriate measurement ...
An abrasion-ablation T-matrix formulation is applied to the calculation of double differential-cross sections in projectile fragmentation of 2.1 GeV/nucleon O-16 on Be-9 and 86 MeV/nucleon C-12 on C-12 and Ag-108. An exponential parameterization of the ablation T-matrix is used and the total width of the intermediate states is taken as ...
A high-power transversely excited atmospheric-pressure (TEA) CO2 laser (600-1500 mJ) was focused on a metal target in surrounding He gas at 1 atm to produce strong He gas breakdown plasma, while leaving the metal surface undamaged, and a Q-switched Nd:YAG laser (60-90 mJ) was also simultaneously focused on the metal surface to be ablated at a slightly ...
Laser plasmas were generated by ablation of aluminum targets via a Nd:YAG glass laser, of pulse energy 0.8 J, and duration 15 ns (full width at half maximum) at the fundamental wavelength (1.064 ?m). Emission lines in the wavelength range of 27-32 nm (45-37.8 eV) were mapped over a spatial range extending out 1.8 mm from the target ...
We report the effect of 'plasma pipe' formation on pulsed laser ablation of organic polymers in air under normal conditions. Ablation of polymers (PMMA, polyimide) is carried out in a wide range of CO2 laser fluences with special attention to plasma formation in the ablation products. Evolution ...
Single and multiple deuterium pellets have been injected into a variety of TFTR plasmas, including ohmically heated plasmas with wide range of electron temperatures, neutral beam heated plasmas at several NBI powers and high T/sub e/, post NBI plasmas. Pe...
A CO{sub 2} laser was operated at pulse energies up to 10 J to ablate polyoxymethylene targets in air and vacuum conditions. Critical effects predicted by ablation models are discussed in relation to the experimental data, including specifically the threshold fluences for vaporization and critical plasma formation, and the fluence at ...
Aluminum plasma was obtained with a Nd:YAG pulsed laser beam ablating target aluminum. The radiation information of the plasma was recorded on a time and space resolution basis. So the time-resolved spectra of Al plasma were obtained with a time delay of 10 to 10,000 ns. From those spectra, we acquired the ...
In addition to visible and near-IR emission, recent investigations have shown that electromagnetic pulses (EMP) in the microwave and RF regions of the spectrum are generated during femtosecond laser-matter interactions if the laser source is sufficiently intense to ablate and ionize an illuminated solid target material. Although the mechanisms for the laserinduced EMP pulse ...
Nozzle wall ablation caused by high temperature electric arcs is studied in the context of high voltage SF6 circuit breakers. The simplified ablation model used in litterature has been updated to take into account the unsteady state of ablation. Ablation rate and velocity are now calculated by a kinetic model using ...
An eight shot pellet injector is used to fuel the HL-1M tokamak from the low field side. The pellet ablation process is investigated with a CCD camera and an array of H? emission detectors. It is observed that the velocity of the pellet ablation cloud is obviously slowed down after it enters the plasma. The ...
Determination of the rates of laser ablation (etching) of various materials by powerful (up to 1014 W cm-2) pulsed radiation revealed a considerable reduction in the etching efficiency during shaping of deep ablation channels. The optical characteristics of the resultant plasma � vapour plume were measured. These measurements and ...
The characteristics of Infra Red femtosecond laser-induced aerosols are studied for monazite (Moacyr) ablation, in order to evaluate optimal conditions for Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) analysis. Various parameters are tested within wide ranges in order to cover near all of the usual LA-ICP-MS settings: pulse energy (E0), pulse ...
We have designed and constructed a spectroscopic interferometer, and test run its operation with a pulsed discharge plasma. The plasma is produced by capacitor discharge across a gap filled with neutral argon at selected pressures. Ablation of iron from the cathode adds to argon to form equilibrium plasma of an ...
This paper is to numerically investigate, in one dimension, the effects of precursor plasma resulted from wire-array ablation on the performance of its following implosion after the ablation. The wire-array ablation is described by an analytic model, which consists of a rocket model or Sasorov's expression ...
Using the plasma model recent developed by the authors, this study predicts the existence of a constant ablation-depth zone with respect to fluence in femtosecond laser ablation of dielectrics, which has also been observed experimentally. It is found that the value of the constant ablation depth is significantly ...
the Miller-Bravais Indexing system for hexagonal crystals. #12;Chapter 5 � Laser Ablation at the Solid/Liquid � Laser Ablation at the Solid/Liquid Interface 173 Figure 5.27: SAED pattern of some crystals found, Contributions to Plasma Physics 40, 46-56 (2000). 11 CRC Handbook of Chemistry and Physics, 14 ed. (CRC Press
The effects of the finite current channel width on the current convective instability are studied both analytically and numerically. First, using a sharp-boundary field-aligned current distribution which has a finite width along the plasma density gradien...
Ablation of fueling pellets has been investigated for intensive neutral beam injection (NBI) heated plasmas in Large Helical Device (LHD). When measured penetration depth of injected pellets in the experiment is compared with a theoretical model employing ablation only due to the heat flux of thermal electrons, systematic deviation ...
Laser ablation on the ultra-short-pulses regime (femtosecond), has an impact on materials processing and micromachining in a quite profound ways. The investigation of the time progression of the laser ablation process within the material can produce much information and it is not conventionally used. The implementation of such study is the main aim of this ...
Femtosecond and nanosecond lasers were compared for ablating brass alloys. All operating parameters from both lasers were equal except for the pulse duration. The ablated aerosol vapor was collected on silicon substrates for particle size measurements or sent into an inductively coupled plasma mass spectrometer. The diameters and size ...
This paper presents a review on the modeling of ablation and plasma expansion processes in the pulsed laser deposition of metals. The ablation of a target is the key process that determines the amount of material to be deposited; while, the plasma expansion governs the characteristics of the deposited material. The ...
The mutual transition dynamics between nonthermal and thermal dominant ablation processes is investigated in the hole-drilling and line-scribing experiments on aluminum samples with intense 50 fs to 24 ps laser pulses. It is found that a critical pulse width that separates the two different ablation regimes monotonically reduces with ...
