Three-dimensional electron number densities in a titanium PLD plasma using interferometry

Doyle, L.A.; Martin, G. W.; Williamson, T.P.; Al‐Khateeb, A.; Weaver, I.; Riley, David; Lamb, Martin; Morrow, Thomas; Lewis, Ciaran

doi:10.1109/27.763085

Cited by 8 publications

(9 citation statements)

References 3 publications

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“…As a result, most papers report Stark broadening equations for the evaluation of n e and its temporal evolution in the plasma. All Htransitions (including Lyman lines 144 ) have been measured, in addition to several nonhydrogenic lines (see Table VI , and Ti 218 targets, in addition to in situ depth profile mapping. 219 A distinct advantage is that no LTE assumption is needed.…”

Section: Expression Description Equation Numbermentioning

confidence: 99%

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Laser-Induced Breakdown Spectroscopy (LIBS), Part I: Review of Basic Diagnostics and Plasma—Particle Interactions: Still-Challenging Issues within the Analytical Plasma Community

2010

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Laser-induced breakdown spectroscopy (LIBS) has become a very popular analytical method in the last decade in view of some of its unique features such as applicability to any type of sample, practically no sample preparation, remote sensing capability, and speed of analysis. The technique has a remarkably wide applicability in many fields, and the number of applications is still growing. From an analytical point of view, the quantitative aspects of LIBS may be considered its Achilles' heel, first due to the complex nature of the laser–sample interaction processes, which depend upon both the laser characteristics and the sample material properties, and second due to the plasma–particle interaction processes, which are space and time dependent. Together, these may cause undesirable matrix effects. Ways of alleviating these problems rely upon the description of the plasma excitation-ionization processes through the use of classical equilibrium relations and therefore on the assumption that the laser-induced plasma is in local thermodynamic equilibrium (LTE). Even in this case, the transient nature of the plasma and its spatial inhomogeneity need to be considered and overcome in order to justify the theoretical assumptions made. This first article focuses on the basic diagnostics aspects and presents a review of the past and recent LIBS literature pertinent to this topic. Previous research on non-laser-based plasma literature, and the resulting knowledge, is also emphasized. The aim is, on one hand, to make the readers aware of such knowledge and on the other hand to trigger the interest of the LIBS community, as well as the larger analytical plasma community, in attempting some diagnostic approaches that have not yet been fully exploited in LIBS.

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Section: Expression Description Equation Numbermentioning

confidence: 99%

“…102 Rayleigh scatter by ground-state argon atoms was used to evaluate T g in a DC arc. 216 , and Ti 218 targets, in addition to in situ depth profile mapping. 219 A distinct advantage is that no LTE assumption is needed.…”

Section: Expressionmentioning

confidence: 99%

Laser-Induced Breakdown Spectroscopy (LIBS), Part I: Review of Basic Diagnostics and Plasma—Particle Interactions: Still-Challenging Issues within the Analytical Plasma Community

2010

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“…We have done this in Fig. 4͑b͒ for three assumptions about the expansion velocity, spanning the expected values from experiment 10 and simulation 32 under the same conditions. It is clear from the results that the electron density does indeed fall faster than expected for a simple 3D expansion.…”

Section: Methodsmentioning

confidence: 99%

“…The plume conditions are of great interest to scientists developing the techniques and have been investigated with a variety of diagnostics. [8][9][10][11][12][13] Recently we have implemented spectrally resolved optical Thomson scatter from such plasmas. 14 This is a powerful diagnostic tool [15][16][17][18] that has been applied to a variety of plasmas including tokamaks, 19,20 high temperature laser plasmas, 21 as well as rf discharge plasmas and arc discharges.…”

Section: Introductionmentioning

confidence: 99%

Optical Thomson scatter from a laser-ablated magnesium plume

Delserieys

Khattak

Lewis

et al. 2009

Journal of Applied Physics

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We have carried out an optical Thomson scatter study of a KrF laser-ablated Mg plume. The evolution of the electron temperature and density at distances 2 -5 mm from the target surface has been studied. We have observed that the electron density falls more rapidly than the atomic density and believe that this is a result of rapid dielectronic recombination. A comparison of the electron density profile and evolution with simple hydrodynamic modeling indicates that there is a strong absorption of the laser in the plasma vapor above the target, probably due to photoionization. We also conclude that an isothermal model of expansion better fits the data than an isentropic expansion model. Finally, we compared data obtained from Thomson scatter with those obtained by emission spectroscopy under similar conditions. The two sets of data have differences but are broadly consistent.

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“…Optical laser interferometry (Benattar et al, 1979;Hariharan, 2003;Schittenhelm et al, 1998;Walkup et al, 1986;Doyle et al, 1999;Villagran-Muniz et al, 2000;Mao et al, 2000) had been verified a convenient, efficient and accurate technique to measure the electron density of plasma generated by short pulse laser. But the capability is limited by two factors: the first one is the critical density and the second is due to the deflection of the probe light in plasma with gradient density (Lisitsyn et al, 1998;Born & Wolf, 1964).…”

Section: Electron Density Measurement With Optical Laser Interferometrymentioning

confidence: 98%

Space-time characterization of laser plasma interactions in the warm dense matter regime

et al. 2007

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Laser plasma interaction experiments have been performed using an fs Titanium Sapphire laser. Plasmas have been generated from planar PMMA targets using single laser pulses with 3.3 mJ pulse energy, 50 fs pulse duration at 800 nm wavelength. The electron density distributions of the plasmas in different delay times have been characterized by means of Nomarski Interferometry. Experimental data were compared with hydrodynamic simulation. First results to characterize the plasma density and temperature as a function of space and time are obtained. This work aims to generate plasmas in the warm dense matter (WDM) regime at near solid-density in an ultra-fast laser target interaction process. Plasmas under these conditions can serve as targets to develop X-ray Thomson scattering as a plasma diagnostic tool, e.g., using the Vacuum ultraviolet (VUV) free-electron laser (FLASH) at Dentsches ElektronenSynchrotron (DESY) Hamburg.

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Three-dimensional electron number densities in a titanium PLD plasma using interferometry

Cited by 8 publications

References 3 publications

Laser-Induced Breakdown Spectroscopy (LIBS), Part I: Review of Basic Diagnostics and Plasma—Particle Interactions: Still-Challenging Issues within the Analytical Plasma Community

Laser-Induced Breakdown Spectroscopy (LIBS), Part I: Review of Basic Diagnostics and Plasma—Particle Interactions: Still-Challenging Issues within the Analytical Plasma Community

Optical Thomson scatter from a laser-ablated magnesium plume

Space-time characterization of laser plasma interactions in the warm dense matter regime

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