Collisional absorption of laser light in under-dense plasma: The role of Coulomb logarithm

Kundu, M.

doi:10.1063/1.4862038

Cited by 10 publications

(16 citation statements)

References 19 publications

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“…However, in som e experim ents [2,35], w ith norm ally incident s-polarized laser light, a was found to increase with 70 up to a m axim um value corresponding to an intensity 7C, and a decrease w hen 70 > 7C. We explained this anom alous increase o f a versus 7<> recently [29] w ith a variant ol CSM [23][24][25] (called ballistic model, BM ) using total velocity v = V u p + u2 dependent 7>max = v/co, and 7>min = Z / v 2 in In A. However, all CSM s using In A have deficiencies and do not always m atch w ith the m ore accurate kinetic m odels [2 2 ,2 6 ,3 2 -3 4 ,3 6 -3 9 ]) o f uei having no In A dependence.…”

Section: Introductionmentioning

confidence: 67%

“…Then we propose a modified &max = u2/Z (for the classical case) or kmax = 2v (for the quantum case), which additionally depends on E{) and co, and show (ii) anomalous increase of vei vs /o tor a given Te < 15 eV. The anomalous variation of vci and corresponding a with /0 (also with Tc) are found only in the low temperature and low intensity regime as in our earlier work [29] with CSM, but it was not explored before with the kinetic models. The proposed km dx in the kinetic model is used to explain experimental results of laser absorption in Ref.…”

Section: Introductionmentioning

confidence: 68%

“…However, in all cases, the universally accepted, conventional feature is that vei/o)p remains almost constant up to a value of i>oMh R* 1, and then it drops rapidly when u0/i>,h > 1. Figure 1 shows normalized frequency ve\/cov versus nor_ malized velocity foMh using expressions (2), (6), (7) and the CSM [25,29] represented by "Bornath-Q," "Bornath-C," "Dawson-C," and "Mulser-C," respectively, for 7C = 25.86 eV.…”

Section: Results For Veimentioning

confidence: 99%

“…A lthough we used CSM in Ref. [29] to show anom alous absorption, the classical form ulation may not be valid in the 1539-3755/2015/91 (4)/043102 (8) 043102-1 ©2015 American Physical Society very low temperature (e.g., Te < 5 eV) regime for the classical nondegenerate plasmas. To overcome the above mentioned limitations of CSM.…”

Section: Introductionmentioning

confidence: 99%

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Anomalous collisional absorption of laser pulses in underdense plasma at low temperature

Kundu

2015

Phys. Rev. E

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In a previous paper [M. Kundu, Phys. Plasmas 21, 013302 (2014)], fractional collisional absorption (α) of laser light in underdense plasma was studied by using a classical scattering model of electron-ion collision frequency ν(ei), where total velocity v=√[v(th)(2)+v(0)(2)] (with v(th) and v(0) as the thermal and the ponderomotive velocity of an electron) dependent Coulomb logarithm lnΛ(v) was shown to be responsible for the anomalous (unconventional) increase of ν(ei) and α(∝ν(ei)) with the laser intensity I(0) up to a maximum value about an intensity I(c) in the low temperature (T(e)<15eV) regime and a conventional ≈I(0)(-3/2) decrease when I(0)≫I(c). One may object that the anomalous increase in ν(ei) and α were partly due to the artifact introduced in lnΛ through the maximum cutoff distance b(max)∝v. In this work, we show similar anomalous increase in ν(ei) and α versus I(0) (in the low temperature and underdense density regime) with more accurate quantum and classical kinetic models of ν(ei) without using lnΛ, but with a proper choice of the total velocity dependent inverse cutoff length k(max)∝v(2) (classical) or k(max)∝v (quantum). For a given I(0)<5×10(14)Wcm(-2), ν(ei) versus T(e) also exhibits so far unnoticed identical anomalous increase as ν(ei) versus I(0), even if the conventional k(max)∝v(th)(2) or k(max)∝v(th) (without v(0)) is chosen. The total velocity dependent k(max) in the kinetic models, as proposed here, is found to explain the anomalous increase of α with I(0) measured in some earlier laser-plasma experiments.

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Section: Introductionmentioning

confidence: 67%

Section: Introductionmentioning

confidence: 68%

Section: Results For Veimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Anomalous collisional absorption of laser pulses in underdense plasma at low temperature

Kundu

2015

Phys. Rev. E

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“…In the absence of ionization of air, the charge state EOS relation (1) simply behaves as the ideal gas equation. With the intensity used in the experiment the plasma is under dense and collisional absorption plays a major role and is used to set initial conditions [15]. The conservation equations of mass, momentum and energy (electron and ion separately) with source terms like laser energy deposition, thermal conduction and electron-ion relaxation was solved using an implicit method.…”

Section: Experimental and Numerical Approachmentioning

confidence: 99%

Development of numerical model to investigate the laser driven shock waves from aluminum target into ambient air at atmospheric pressure and its comparison with experiment

Shiva¹,

Leela²,

Chaturvedi³

et al. 2017

AIP Conference Proceedings

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Calculation of the inverse bremsstrahlung absorption in unmagnetized plasmas

Farrashbandi

Eslami‐Kalantari

2019

Contributions to Plasma Physics

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Inverse bremsstrahlung is one important way to deliver laser energy to the plasma in inertial confinement fusion. In this article, we study the collisional absorption rate as obtained from the Fokker-Planck treatment of an unmagnetized plasma in harmonic laser field. The electron-ion collision rate is considered in the Krook approximation, and the electron distribution function is considered a Maxwellian function. We evaluate the inverse bremsstrahlung absorption near the irradiated plasma surface in the critical layer. We observe that absorption increases with shorter laser wavelength and lower electron temperatures. When the maximum electron velocity in the limit of q → 1 reaches infinity, the q-non-extensive distribution function reduces to the standard Maxwell-Boltzmann distribution. K E Y W O R D Sabsorption, collision, inertial confinement fusion, inverse bremsstrahlung, laser plasma

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Collisional absorption of laser light in under-dense plasma: The role of Coulomb logarithm

Cited by 10 publications

References 19 publications

Anomalous collisional absorption of laser pulses in underdense plasma at low temperature

Anomalous collisional absorption of laser pulses in underdense plasma at low temperature

Development of numerical model to investigate the laser driven shock waves from aluminum target into ambient air at atmospheric pressure and its comparison with experiment

Calculation of the inverse bremsstrahlung absorption in unmagnetized plasmas

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