scholarly journals Charged Particle Oscillations in Transient Plasmas Generated by Nanosecond Laser Ablation on Mg Target

Symmetry ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 292 ◽  
Author(s):  
Maricel Agop ◽  
Ilarion Mihaila ◽  
Florin Nedeff ◽  
Stefan Andrei Irimiciuc
Keyword(s):  
Charged Particle ◽  
Laser Ablation ◽  
Particle Density ◽  
Plasma Potential ◽  
The Self ◽  
Tunneling Effect ◽  
Nanosecond Laser ◽  
Plasma Parameters ◽  
Temperature Plasma ◽  
Laser Produced Plasma

The dynamics of a transient plasma generated by laser ablation on a Mg target was investigated by means of the Langmuir probe method and fractal analysis. The empirical data showcased the presence of an oscillatory behavior at short expansion times (<1 μs) characterized by two oscillation frequencies and a classical behavior for longer evolution times. Space- and time-resolved analysis was implemented in order to determine main plasma parameters like the electron temperature, plasma potential, or charged particle density. In the motion fractal paradigm, a theoretical model was built for the description of laser-produced plasma dynamics expressed through fractal-type equations. The calibration of such dynamics was performed through a fractal-type tunneling effect for physical systems with spontaneous symmetry breaking. This allows both the self-structuring of laser-produced plasma in two structures based on its separation on different oscillation modes and the determination of some characteristics involved in the self-structuring process. The mutual conditionings between the two structures are given as joint invariant functions on the action of two isomorph groups of SL(2R) type through the Stoler-type transformation, explicitly given through amplitude self-modulation.

Comparison of copper and brass plasma parameters produced by nanosecond laser-ablation

2014 ◽  
Vol 26 (2) ◽  
pp. 22011
Author(s):  
赵小侠 Zhao Xiaoxia ◽  
贺俊芳 He Junfang ◽  
王红英 Wang Hongying ◽  
杨森林 Yang Senlin ◽  
李院院 Li Yuanyuan ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Nanosecond Laser ◽  
Plasma Parameters ◽  
Nanosecond Laser Ablation

scholarly journals Prompt electrons driving ion acceleration and formation of a two-temperature plasma in nanosecond laser-ablation domain

2012 ◽  
Vol 100 (4) ◽  
pp. 45003 ◽  
Author(s):  
D. Mascali ◽  
S. Tudisco ◽  
N. Gambino ◽  
A. Pluchino ◽  
A. Anzalone ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Ion Acceleration ◽  
Nanosecond Laser ◽  
Temperature Plasma ◽  
Nanosecond Laser Ablation ◽  
Two Temperature

Study of moving striations in plasmas. I. Measurement of the phase between the variations of several plasma parameters

1968 ◽  
Vol 46 (16) ◽  
pp. 1787-1793 ◽  
Author(s):  
Michel G. Drouet ◽  
Miloš Šicha
Keyword(s):  
Light Intensity ◽  
Electric Field ◽  
Electron Temperature ◽  
Discharge Current ◽  
Plasma Potential ◽  
Plasma Parameters ◽  
Temperature Plasma ◽  
Continuous Waves ◽  
Slow Moving ◽  
Made In

The phases between the variations of electron density, electron temperature, plasma potential, electric field, and light intensity have been measured in slow-moving striations in a neon discharge for different values of the discharge current. The reported measurements were made in moving striations artificially excited in the form of both continuous waves and wave of stratification.

scholarly journals Discrimination of ablation, shielding, and interface layer effects on the steady-state formation of persistent bubbles under liquid flow conditions during laser synthesis of colloids

2021 ◽  
Author(s):  
Mark-Robert Kalus ◽  
Riskyanti Lanyumba ◽  
Stephan Barcikowski ◽  
Bilal Gökce
Keyword(s):  
Steady State ◽  
Laser Ablation ◽  
Liquid Flow ◽  
Production Efficiency ◽  
Synthesis Method ◽  
Target Surface ◽  
Interface Layer ◽  
Nanosecond Laser ◽  
Viscous Liquids ◽  
Shielding Effects

AbstractOver the past decade, laser ablation in liquids (LAL) was established as an innovative nanoparticle synthesis method obeying the principles of green chemistry. While one of the main advantages of this method is the absence of stabilizers leading to nanoparticles with “clean” ligand-free surfaces, its main disadvantage is the comparably low nanoparticle production efficiency dampening the sustainability of the method and preventing the use of laser-synthesized nanoparticles in applications that require high amounts of material. In this study, the effects of productivity-dampening entities that become particularly relevant for LAL with high repetition rate lasers, i.e., persistent bubbles or colloidal nanoparticles (NPs), on the synthesis of colloidal gold nanoparticles in different solvents are studied. Especially under batch ablation conditions in highly viscous liquids with prolonged ablation times both shielding entities are closely interconnected and need to be disentangled. By performing liquid flow-assisted nanosecond laser ablation of gold in liquids with different viscosity and nanoparticle or bubble diffusivity, it is shown that a steady-state is reached after a few seconds with fixed individual contributions of bubble- and colloid-induced shielding effects. By analyzing dimensionless numbers (i.e., Axial Peclet, Reynolds, and Schmidt) it is demonstrated how these shielding effects strongly depend on the liquid’s transport properties and the flow-induced formation of an interface layer along the target surface. In highly viscous liquids, the transport of NPs and persistent bubbles within this interface layer is strongly diffusion-controlled. This diffusion-limitation not only affects the agglomeration of the NPs but also leads to high local densities of NPs and bubbles near the target surface, shielding up to 80% of the laser power. Hence, the ablation rate does not only depend on the total amount of shielding matter in the flow channel, but also on the location of the persistent bubbles and NPs. By comparing LAL in different liquids, it is demonstrated that 30 times more gas is produced per ablated amount of substance in acetone and ethylene glycol compared to ablation in water. This finding confirms that chemical effects contribute to the liquid’s decomposition and the ablation yield as well. Furthermore, it is shown that the highest ablation efficiencies and monodisperse qualities are achieved in liquids with the lowest viscosities and gas formation rates at the highest volumetric flow rates.

scholarly journals Micro- and nanoparticle generation during nanosecond laser ablation: correlation between mass and optical emissions

2014 ◽  
Vol 22 (4) ◽  
pp. 3991 ◽  
Author(s):  
Santiago Palanco ◽  
Salvatore Marino ◽  
M. Gabás ◽  
Shanti Bijani ◽  
Luis Ayala ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Nanosecond Laser ◽  
Optical Emissions ◽  
Nanosecond Laser Ablation ◽  
Nanoparticle Generation

Generation of Efficient Terahertz Radiation by Relativistic Self-Focusing of A Cosh-Gaussian Laser Beam in A Magnetized Plasma

2021 ◽  
Author(s):  
Gunjan Purohit ◽  
Bineet Gaur ◽  
Pradeep Kothiyal ◽  
Amita Raizada
Keyword(s):  
Laser Beam ◽  
Numerical Study ◽  
The Self ◽  
Magnetized Plasma ◽  
Thz Radiation ◽  
Gaussian Laser Beam ◽  
Plasma Parameters ◽  
Gaussian Profile ◽  
Self Focusing ◽  
Incident Laser Intensity

Abstract This paper presents a scheme for the generation of terahertz (THz) radiation by self-focusing of a cosh-Gaussian laser beam in the magnetized and rippled density plasma, when relativistic nonlinearity is operative. The strong coupling between self-focused laser beam and pre-existing density ripple produces nonlinear current that originates THz radiation. THz radiation is produced by the interaction of the cosh-Gaussian laser beam with electron plasma wave under the appropriate phase matching conditions. Expressions for the beamwidth parameter of cosh-Gaussian laser beam and the electric vector of the THz radiation have been obtained using higher-order paraxial theory and solved numerically. The self-focusing of the cosh-Gaussian laser beam and its effect on the generated THz amplitude have been studied for specific laser and plasma parameters. Numerical study has been performed on various values of the decentered parameter, incident laser intensity, magnetic field, and relative density. The results have also been compared with the paraxial region as well as the Gaussian profile of laser beam. Numerical results suggest that the self-focusing of the cosh-Gaussian laser beam and the amplitude of THz radiation increase in the extended paraxial region compared to the paraxial region. It is also observed that the focusing of the cosh-Gaussian laser beam in the magnetized plasma and the amplitude of the THz radiation increases at higher values of the decentered parameter.

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