Three-dimensional hybrid optoacoustic imaging of the laser-induced plasma and deposited energy density under optical breakdown in water

2021 ◽  
Vol 118 (1) ◽  
pp. 011109
Author(s):  
B. V. Rumiantsev ◽  
E. I. Mareev ◽  
A. S. Bychkov ◽  
A. A. Karabutov ◽  
E. B. Cherepetskaya ◽  
...  
Keyword(s):  
Energy Density ◽  
Three Dimensional ◽  
Optical Breakdown ◽  
Optoacoustic Imaging ◽  
Laser Induced Plasma ◽  
Deposited Energy

Simulation of Ultrashort Laser Pulse Absorption At the Water-metal Interface in Laser-Induced Plasma Micro-Machining

2020 ◽  
Author(s):  
Jiaxi Xie ◽  
Kornel Ehmann ◽  
Jian Cao
Keyword(s):  
Dielectric Breakdown ◽  
Constitutive Relations ◽  
Three Dimensional ◽  
Optical Breakdown ◽  
Micro Machining ◽  
Metal Interface ◽  
Breakdown Threshold ◽  
Laser Induced Plasma ◽  
Water Metal ◽  
Ultrashort Laser

Abstract This work proposes a physically consistent numerical model to simulate ultrashort laser absorption by a metallic workpiece at the water-metal interface when optical breakdown of the dielectric occurs. The simulation couples the framework of the Finite-Difference Time-Domain method used in computational electromagnetics with the constitutive relation derived from both the model of direct ablation of metals and the first order model of water breakdown. The simulation is used to describe interface ablation processes such as Laser-Induced Plasma Micro-Machining. Applied to the water-aluminum interface, the model is able to describe the metal absorption and the dielectric breakdown threshold in three-dimensional geometry. It is an extensible monolithic approach in which the absorption by different materials can be described by simply changing the constitutive relations.

scholarly journals Alternative derivation of the higher-order constitutive model for six-parameter elastic shells

2021 ◽  
Vol 72 (2) ◽  
Author(s):  
Mircea Bîrsan
Keyword(s):  
Energy Density ◽  
Constitutive Model ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Shell Theory ◽  
Constitutive Relations ◽  
Three Dimensional ◽  
Classical Shell Theory ◽  
Three Dimensional Elasticity ◽  
General Method

AbstractIn this paper, we present a general method to derive the explicit constitutive relations for isotropic elastic 6-parameter shells made from a Cosserat material. The dimensional reduction procedure extends the methods of the classical shell theory to the case of Cosserat shells. Starting from the three-dimensional Cosserat parent model, we perform the integration over the thickness and obtain a consistent shell model of order $$ O(h^5) $$ O ( h 5 ) with respect to the shell thickness h. We derive the explicit form of the strain energy density for 6-parameter (Cosserat) shells, in which the constitutive coefficients are expressed in terms of the three-dimensional elasticity constants and depend on the initial curvature of the shell. The obtained form of the shell strain energy density is compared with other previous variants from the literature, and the advantages of our constitutive model are discussed.

scholarly journals Thermalization of synchrotron radiation from field-aligned currents

1988 ◽  
Vol 6 (3) ◽  
pp. 493-501 ◽  
Author(s):  
William Peter ◽  
Anthony L. Peratt
Keyword(s):  
Magnetic Field ◽  
Synchrotron Radiation ◽  
Energy Density ◽  
Radiation Spectrum ◽  
Axial Magnetic Field ◽  
Three Dimensional ◽  
Synchrotron Emission ◽  
Microwave Background ◽  
Strong Function ◽  
Current Filaments

Three-dimensional plasma simulations of interacting galactic-dimensioned current filaments show bursts of synchroton radiation of energy density 1·2 ×10−13 erg/cm3 which can be compared with the measured cosmic microwave background energy density of 1·5 × 10−13 erg/cm3. However, the synchrotron emission observed in the simulations is not blackbody. In this paper, we analyze the absorption of the synchrotron emission by the current filaments themselves (i.e., self-absorption) in order to investigate the thermalization of the emitted radiation. It is found that a large number of current filaments (>1031) are needed to make the radiation spectrum blackbody up to the observed measured frequency of 100 GHz. The radiation spectrum and the required number of current filaments is a strong function of the axial magnetic field in the filaments.

scholarly journals Worldline numerics applied to custom Casimir geometry generates unanticipated intersection with Alcubierre warp metric

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
Harold White ◽  
Jerry Vera ◽  
Arum Han ◽  
Alexander R. Bruccoleri ◽  
Jonathan MacArthur
Keyword(s):  
Energy Density ◽  
Three Dimensional ◽  
Casimir Energy ◽  
Negative Energy ◽  
Vacuum Model ◽  
Energy Density Distribution ◽  
Dynamic Vacuum ◽  
Negative Energy Density ◽  
Funded Project ◽  
Transient Electric Field

AbstractWhile conducting analysis related to a DARPA-funded project to evaluate possible structure of the energy density present in a Casimir cavity as predicted by the dynamic vacuum model, a micro/nano-scale structure has been discovered that predicts negative energy density distribution that closely matches requirements for the Alcubierre metric. The simplest notional geometry being analyzed as part of the DARPA-funded work consists of a standard parallel plate Casimir cavity equipped with pillars arrayed along the cavity mid-plane with the purpose of detecting a transient electric field arising from vacuum polarization conjectured to occur along the midplane of the cavity. An analytic technique called worldline numerics was adapted to numerically assess vacuum response to the custom Casimir cavity, and these numerical analysis results were observed to be qualitatively quite similar to a two-dimensional representation of energy density requirements for the Alcubierre warp metric. Subsequently, a toy model consisting of a 1 $$\upmu $$ μ m diameter sphere centrally located in a 4 $$\upmu $$ μ m diameter cylinder was analyzed to show a three-dimensional Casimir energy density that correlates well with the Alcubierre warp metric requirements. This qualitative correlation would suggest that chip-scale experiments might be explored to attempt to measure tiny signatures illustrative of the presence of the conjectured phenomenon: a real, albeit humble, warp bubble.

scholarly journals Brownian motion and polarized three-dimensional quantum vacuum

2021 ◽  
Vol 67 (4 Jul-Aug) ◽  
Author(s):  
Davide Fiscaletti
Keyword(s):  
Dark Matter ◽  
Brownian Motion ◽  
Energy Density ◽  
Nonlinear Model ◽  
Vacuum Energy ◽  
Three Dimensional ◽  
Vacuum Energy Density ◽  
Quantum Vacuum ◽  
Virtual Particles ◽  
Fundamental Entity

A nonlinear model of Brownian motion is developed in a three-dimensional quantum vacuum defined by a variable quantum vacuum energy density corresponding to processes of creation/annihilation of virtual particles. In this model, the polarization of the quantum vacuum determined by a perturbative fluctuation of the quantum vacuum energy density associated with a fluctuating viscosity, which mimics the action of dark matter, emerges as the fundamental entity which generates the Brownian motion.

Fatigue Strength of Three Dimensional Welded Joints: A Synthesis Based on the Strain Energy Density over a Control Volume

2007 ◽  
Vol 348-349 ◽  
pp. 413-416
Author(s):  
M. Zappalorto ◽  
Filippo Berto ◽  
Paolo Lazzarin
Keyword(s):  
Experimental Data ◽  
Energy Density ◽  
Welded Joints ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Complex Geometry ◽  
Control Volume ◽  
Three Dimensional ◽  
Weld Toe ◽  
Weld Root

A recent approach based on the local strain energy density (SED) averaged over a given control volume is applied to well documented experimental data taken from the literature, all related to steel welded joints of complex geometry. This small size volume embraces the weld root or the weld toe, both regions modelled as sharp (zero notch radius) V-notches with different opening angles. The SED is evaluated from three-dimensional finite element models by using a circular sector with a radius equal to 0.28 mm. The data expressed in terms of the local energy fall in a scatter band recently reported in the literature, based on about 650 experimental data related to fillet welded joints made of structural steel with failures occurring at the weld toe or at the weld root.

A three-dimensional graphene framework-enabled high-performance stretchable asymmetric supercapacitor

2018 ◽  
Vol 6 (4) ◽  
pp. 1802-1808 ◽  
Author(s):  
Ke Li ◽  
Yanshan Huang ◽  
Jingjing Liu ◽  
Mansoor Sarfraz ◽  
Phillips O. Agboola ◽  
...  
Keyword(s):  
Energy Density ◽  
High Performance ◽  
Three Dimensional ◽  
High Energy ◽  
Cycling Stability ◽  
High Energy Density ◽  
Asymmetric Supercapacitor ◽  
Asymmetric Supercapacitors ◽  
Superior Cycling Stability

Three-dimensional graphene frameworks enable the development of stretchable asymmetric supercapacitors with a record high energy density of 77.8 W h kg−1, and also excellent stretchability and superior cycling stability.

Real-time three-dimensional optoacoustic imaging using an acoustic lens system

2004 ◽  
Vol 85 (5) ◽  
pp. 846-848 ◽  
Author(s):  
J. J. Niederhauser ◽  
M. Jaeger ◽  
M. Frenz
Keyword(s):  
Real Time ◽  
Three Dimensional ◽  
Lens System ◽  
Optoacoustic Imaging ◽  
Acoustic Lens
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