Spatially and temporally discontinuous two-plasmon decay with relatively low laser irradiance

2020 ◽  
Vol 62 (12) ◽  
pp. 125001
Author(s):  
Ning Kang ◽  
Huiya Liu ◽  
Anle Lei ◽  
Shengzhe Ji ◽  
Shenlei Zhou
Keyword(s):  
1976 ◽  
Vol 15 (5) ◽  
pp. 1172 ◽  
Author(s):  
V. P. Aksenov ◽  
K. S. Gochelashvily ◽  
V. I. Shishov

2007 ◽  
Vol 25 (1) ◽  
pp. 23-30 ◽  
Author(s):  
T. DESAI ◽  
R. DEZULIAN ◽  
D. BATANI

We present one-dimensional simulations performed using the multi group radiation hydro code MULTI with the goal of analyzing the target preheating effect under conditions similar to those of recent experiments aimed at studying the Equation of State (EOS) of various materials. In such experiments, aluminum is often used as reference material; therefore its behavior under strong shock compression and high-intensity laser irradiation (1013–1014 W/cm2) should be studied in detail. Our results reveal that at high laser irradiance, the laser energy available to induce shock pressure is reduced due to high X-rays generation. Simultaneously X-rays preheat the bulk of the reference material causing significant heating prior to shock propagation. Such effects induce deviations in shock propagation with respect to cold aluminum.


2018 ◽  
Vol 53 (11) ◽  
pp. 1459-1473 ◽  
Author(s):  
Shiva Dayal Rao B ◽  
Abhijeet Sethi ◽  
Alok Kumar Das

In the present investigation, a continuous wave fiber laser with maximum power of 400 W was used to cut a glass fiber reinforced plastic sheet of 4.56 mm thickness using Nitrogen as assisting gas. The influence processing parameters such as laser irradiance, gas pressure, and cutting speed on the cut surface quality were investigated by using response surface methodology. The different responses of laser cut surface such as upper kerf width, taper percentage along the cut depth, and heat-affected zone on the top surface were measured to analyze the influence of input process parameters on the responses. A statistical analysis on the obtained results was conducted and found that the optimum values of different input process parameters were laser irradiance: 8.28 × 105 watt/cm2, cutting speed: 600 mm/min and assisting gas pressure: 7.84 bar. The corresponding values of responses were upper kerf width: 177.4 µm, taper 0.73%, and heat-affected zone on top surface: 109.23 µm. The confirmation experiments were conducted with the obtained optimum parameter setting and observed that the predicted values and experimental values for upper kerf width, taper percentage and top surface heat-affected zone were within the error limits of 2.52%, 1.84%, and 0.45%, respectively. Furthermore, damages like loose fibers, interlayer fractures, evaporation of matrix material and fiber breakages were observed.


2014 ◽  
Vol 32 (2) ◽  
pp. 243-251 ◽  
Author(s):  
Shalom Eliezer ◽  
Noaz Nissim ◽  
Erez Raicher ◽  
José Maria Martínez-Val

AbstractThis paper analyzes the one dimensional shock wave created in a planar target by the ponderomotive force induced by very high laser irradiance. The laser-induced relativistic shock wave parameters, such as compression, pressure, shock wave and particle flow velocities, sound velocity and temperature are calculated here for the first time in the context of relativistic hydrodynamics. For solid targets and laser irradiance of about 2 × 1024 W/cm2, the shock wave velocity is larger than 50% of the speed of light, the shock wave compression is larger than 4 (usually of the order of 10) and the targets have a pressure of the order of 1015 atmospheres. The estimated temperature can be larger than 1 MeV in energy units and therefore very excited physics (like electron positron formation) is expected in the shocked area. Although the next generation of lasers might allow obtaining relativistic shock waves in the laboratory this possibility is suggested in this paper for the first time.


2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Marek Tulej ◽  
Andreas Riedo ◽  
Maria Iakovleva ◽  
Peter Wurz

We present results from mass spectrometric analysis of NIST standard materials and meteoritic samples conducted by a miniaturised laser ablation mass spectrometer designed for space research. The mass analyser supports investigation with a mass resolution () ≈ 500–600 and dynamic range within seven decades. Nevertheless, to maintain an optimal spectral quality laser irradiances lower than ~1 GW/cm2 are applied so far which results in a spread of RSC values. To achieve the quantitative performance of mass analyser, various effects influencing RSC factors have to be investigated. In this paper we investigate influence of laser irradiance, sampling procedure and plasma chemistry on the quantitative elemental and isotopic analysis. The studies indicate necessity for accurate control of laser characteristics and acquisition procedure. A relatively low irradiance applied causes a negligible sample damage and allows for accumulation of large number of waveforms from one sample location. The procedure yields statistically well averaged data and allows a sensitive in-depth analysis. The quantitative analyses of isotopic composition can be performed with accuracy and precision better as 1% and 2%, for isotopic patterns of elements and clusters, respectively. The numerical integration methods would be preferred to achieve more accurate results. The measurements of Allende sample yield detection of Pb isotopic pattern, nevertheless cluster species are readily observed in spectrum and make the elemental analysis of other trace elements difficult due to isobaric interferences. These detections are of a considerable interest because of possible application of the instrument for in situ elemental and isotopic analysis and radiometric dating of solids.


2007 ◽  
Vol 23 (4) ◽  
pp. 381-384 ◽  
Author(s):  
V. Haxsen ◽  
D. Schikora ◽  
U. Sommer ◽  
A. Remppis ◽  
J. Greten ◽  
...  

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