scholarly journals Reduction of Reflection from Conducting Surfaces using Plasma Shielding

10.5772/16751 ◽  
2011 ◽  
Author(s):  
Cigdem Seckin ◽  
Emrah Oncu
Keyword(s):  
Plasma Shielding

scholarly journals Modeling of pulsed laser ablation of aluminum under the action of infrared nanosecond laser pulses

2019 ◽  
Vol 196 ◽  
pp. 00020
Author(s):  
Nikolay Rubtsov ◽  
Victor Bessmeltsev ◽  
Maksim Grishin
Keyword(s):  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Laser Pulses ◽  
Ablation Depth ◽  
Aluminum Surface ◽  
Nanosecond Laser ◽  
Ablation Process ◽  
Nanosecond Pulses ◽  
Nanosecond Laser Pulses ◽  
Plasma Shielding

The paper presents the results of numerical simulation of aluminum ablation process that is caused by a series of incident nanosecond pulses on a wavelength λ=1064 nm. The mechanism of normal evaporation and the effect of plasma shielding were taken into account. As a result of mathematical modeling the ablation depth was obtained. It is shown that plasma shielding reduces the effectiveness of ablation process much more than cooling of the aluminum surface between pulses.

Transient Analysis of Laser Ablation Process With Plasma Shielding: One-Dimensional Model Using Finite Volume Method

2013 ◽  
Vol 1 (1) ◽  
Author(s):  
Deepak Marla ◽  
Upendra V. Bhandarkar ◽  
Suhas S. Joshi
Keyword(s):  
Laser Ablation ◽  
Finite Volume Method ◽  
Finite Volume ◽  
Ablation Depth ◽  
Transient Model ◽  
Laser Ablation Process ◽  
High Fluences ◽  
Laser Fluences ◽  
Volume Method ◽  
Plasma Shielding

This paper presents a comprehensive transient model of various phenomena that occur during laser ablation of TiC target at subnanosecond time-steps. The model is a 1D numerical simulation using finite volume method (FVM) on a target that is divided into subnanometric layers. The phenomena considered in the model include: plasma initiation, uniform plasma expansion, plasma shielding of incoming radiation, and temperature dependent material properties. It is observed that, during the target heating, phase transformations of any layer occur within a few picoseconds, which is significantly lower than the time taken for it to reach boiling point (~ns). The instantaneous width of the phase transformation zones is observed to be negligibly small (<5nm). In addition, the width of the melt zone remains constant once ablation begins. The melt width decreases with an increase in fluence and increases with an increase in pulse duration. On the contrary, the trend in the ablation depth is exactly opposite. The plasma absorbs about 25–50% of the incoming laser radiation at high fluences (20-40 J/cm2), and less than 5% in the range of 5-10 J/cm2. The simulated results of ablation depth on TiC are in good agreement at lower fluences. At moderate laser fluences (10-25 J/cm2), the discrepancy of the error increases to nearly ±7%. Under prediction of ablation depth by 15% at high fluences of 40 J/cm2 suggests the possibility of involvement of other mechanisms of removal such as melt expulsion and phase explosion at very high fluences.

scholarly journals The influence of plasma shielding effect on laser-ablated copper samples: a focus on signal-to-background ratio and plasma expansion

2016 ◽  
Vol 34 (3) ◽  
pp. 493-505 ◽  
Author(s):  
M. Pishdast ◽  
A. Eslami Majd ◽  
M. Kavosh Tehrani
Keyword(s):  
Plasma Plume ◽  
Laser Intensity ◽  
Strong Shock ◽  
Gas Pressure ◽  
Shielding Effect ◽  
Probe Laser ◽  
Scattering Method ◽  
Background Ratio ◽  
Ambient Gas ◽  
Plasma Shielding

AbstractThe influence of plasma shielding effect induced by ambient gas pressure and laser intensity on the laser-produced Cu plasma parameters, signal-to-background ratio (S/B) and expansion are experimentally and numerically investigated. A Q-switched Nd:YAG laser at 1064 nm at various intensities ranging from 2 to 7.1 GW/cm2 intensity (40–150 mJ) is used to produce Cu plasma in air, argon (Ar), helium (He), and neon (Ne) ambient gas at various pressures ranging from 5 to 1000 mbar. Laser-induced breakdown spectroscopy reveals that spectral radiation, S/B, electron temperature, number density, and front edge velocity of the plasma have an increasing trend up to a certain value of laser intensity and gas pressure. Afterwards, a saturation trend is achieved, which is attributed to the shielding and self-regulation effect. The numerical modeling of the laser-produced Cu plasma in the presence of air at atmospheric pressure is carried out using the MULTI radiation hydrodynamics code. We have shown that the feature of plasma shielding effect observed in the experiments can be reproduced using a continuum hydrodynamics model. Laser intensity at about 3.5 GW/cm2 is found to produce the highest S/B at 1000 mbar air. He, Ne, air, and Ar show the best S/B, respectively and the best S/B is found for air, Ar, He, and Ne at 10, 5, 10, and 20 mbar, respectively. The expansion of plasma plume is studied using a simple and effective technique based on probe laser absorption and scattering method. The plasma plume expansion through He, Ne, air, and Ar at 1000 mbar pressure has the highest velocity, respectively. The simulated results of strong shock wave model and Rankine–Hugoniot jump condition are fitted to the experimental data, which are then used to estimate the values of the ablation parameters.

scholarly journals Excitation of Interstellar OH by Plasma Shielding Currents.

1967 ◽  
Vol 72 ◽  
pp. 800
Author(s):  
Howard D. Greyber
Keyword(s):  
Plasma Shielding

Effect of laser parameters on plasma shielding in single and double pulse configurations during the ablation of an aluminium target

2009 ◽  
Vol 42 (22) ◽  
pp. 225207 ◽  
Author(s):  
G Cristoforetti ◽  
G Lorenzetti ◽  
P A Benedetti ◽  
E Tognoni ◽  
S Legnaioli ◽  
...  
Keyword(s):  
Double Pulse ◽  
Laser Parameters ◽  
Aluminium Target ◽  
Plasma Shielding
Sign in / Sign up

Export Citation Format

Share Document