Evidence of inverse bremsstrahlung in laser enhanced laser-induced plasma

Wiggins, Delonia; Raynor, C.T.; Johnson, J. A.

doi:10.1063/1.3501995

Cited by 19 publications

(6 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…During the isothermal expansion regime, initially the laser interacts with the target and when the initial low density, low temperature plasma plume is formed, collisional ionization and excitation, coupled with the remainder of the laser pulse energy rapidly heats and ionizes the plasma. 13 During adiabatic expansion regime, the plasma expands freely into vacuum. The entire process of nanosecond laser ablation, plasma formation, and expansion has been studied extensively by various groups using various plasma diagnostic tools and has been extensively modeled.…”

Section: Introductionmentioning

confidence: 99%

Experimental and computational study of complex shockwave dynamics in laser ablation plumes in argon atmosphere

et al. 2012

View full text Add to dashboard Cite

We investigated spatio-temporal evolution of ns laser ablation plumes at atmospheric pressure, a favored condition for laser-induced breakdown spectroscopy and laser-ablation inductively coupled plasma mass-spectrometry. The 1064 nm, 6 ns pulses from a Nd:YAG laser were focused on to an Al target and the generated plasma was allowed to expand in 1 atm Ar. The hydrodynamic expansion features were studied using focused shadowgraphy and gated 2 ns self-emission visible imaging. Shadowgram images showed material ejection and generation of shock fronts. A secondary shock is observed behind the primary shock during the time window of 100-500 ns with instabilities near the laser cone angle. By comparing the self-emission images obtained using fast photography, it is concluded that the secondary shocks observed in the shadowgraphy were generated by fast moving target material. The plume front estimates using fast photography exhibited reasonable agreement with data obtained from shadowgraphy at early times ≤400 ns. However, at later times, fast photography images showed plume confinement while the shadowgraphic images showed propagation of the plume front even at greater times. The structure and dynamics of the plume obtained from optical diagnostic tools were compared to numerical simulations. We have shown that the main features of plume expansion in ambient Ar observed in the experiments can be reproduced using a continuum hydrodynamics model which provided valuable insight into the expansion dynamics and shock structure of the plasma plume.

show abstract

Section: Introductionmentioning

confidence: 99%

Experimental and computational study of complex shockwave dynamics in laser ablation plumes in argon atmosphere

et al. 2012

View full text Add to dashboard Cite

show abstract

“…3 the complexity of the plasma increases for the neutral line as the cw laser increases. The enhancement to the ion energy is probably due to inverse bremsstrahlung [17] which provides energizing collisions between the electrons and the positive ions. Thus, the number of variables needed to describe the plasma increases for the neutral nitrogen line.…”

Section: Resultsmentioning

confidence: 99%

“…8 the turbulent energy decreases for the neutral line and increases for the ion line as the cw fiber laser irradiance increases. The enhancement to the ion energy is probably due to inverse bremsstrahlung [17] which provides energizing collisions between the electrons and the positive ions. The decrease in the neutral energies is probably also a byproduct of inverse bremsstrahlung since the energetic neutrals can be more easily excited to higher states (alternative to the neutral line being monitored) by the electrons and thereby reduce the overall energy content of the neutral species being tracked.…”

Section: Resultsmentioning

confidence: 99%

Turbulence changes in laser enhanced laser induced plasmas

Wiggins¹,

Raynor²,

Johnson³

2010

J. Plasma Phys.

Self Cite

View full text Add to dashboard Cite

A neodymium-doped yttrium aluminum garnet laser of wavelength 0.532 µm with the maximum energy of 900 mJ creates plasmas at a focal point in air in the path of a 1 kW continuous wave fiber laser of wavelength 1.08 µm. We find that there is an unexpected influence on a standard set of turbulent parameters in these laser-induced plasmas. Specifically, the continuous wave laser increased the complexity in the turbulent fluctuations. The continuous wave laser reduces the characteristic fluctuation frequencies in the neutral lines. Furthermore, the continuous wave laser enhances turbulence energies in ions while it diminishes turbulence energies in neutrals.

show abstract

“…Where m e is electron mass, ν is laser beam frequency and γ g is a constant called Euler-Mascheroni = 1.781 (14). The energy absorbed by the electrons in plasma from the laser beam per unit length Q A (t) is given by eq.…”

Section: Theorymentioning

confidence: 99%

Enhancement of Electron Temperature under Dense Homogenous Plasma by Pulsed Laser Beam

Yahya

2021

Baghdad Sci.J

View full text Add to dashboard Cite

The applications of hot plasma are many and numerous applications require high values of the temperature of the electrons within the plasma region. Improving electron temperature values is one of the important processes for using this specification in plasma for being adopted in several modern applications such as nuclear fusion, plating operations and in industrial applications. In this work, theoretical computations were performed to enhance electron temperature under dense homogeneous plasma. The effect of power and duration time of pulsed Nd:YAG laser was studied on the heating of plasmas by inverse bremsstrahlung for several values for the electron density ratio. There results for these calculations showed that the effect of increasing the values of the laser pulse power (25-250kW) led to decrease the absorption coefficient values by 58.3% and increase the electron temperature by 50.0% at duration pulse time 0.5ns and electron density ratio 0.1. Furthermore, the ratio of electron density increasing and pulse duration time led to increase the higher values of the electron temperature. The results of the calculations showed the effect of the laser power, the percentage of electron density, and the pulse duration for improving the electron temperature. It is possible to control the temperature of the electrons with one of the plasma parameters or the laser beam used, and that it gives a clear indication of researchers in this field to choose the optimal wavelength of the laser beam and electron density ratios for the plasma.

show abstract

Evidence of inverse bremsstrahlung in laser enhanced laser-induced plasma

Cited by 19 publications

References 13 publications

Experimental and computational study of complex shockwave dynamics in laser ablation plumes in argon atmosphere

Experimental and computational study of complex shockwave dynamics in laser ablation plumes in argon atmosphere

Turbulence changes in laser enhanced laser induced plasmas

Enhancement of Electron Temperature under Dense Homogenous Plasma by Pulsed Laser Beam

Contact Info

Product

Resources

About