ASPEN: A Fully Kinetic, Reduced-Description Particle-in-Cell Model for Simulating Parametric Instabilities

Vu, H. X.; Bezzerides, B.; DuBois, D. F.

doi:10.1006/jcph.1999.6350

Cited by 25 publications

(9 citation statements)

References 33 publications

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“…Actually, since these experimental results have been published, several "reduced" models (see for example Refs. [6][7][8][9][10][11], relying on the hypothesis that the electric field amplitudes may be considered as slowly varying envelopes, have been introduced in order to recover the so-called "kinetic inflation" of Raman reflectivity described in Ref. 5.…”

Section: Introductionmentioning

confidence: 99%

Comparisons between nonlinear kinetic modelings of simulated Raman scattering using envelope equations

2012

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In this paper, we compare two recent models [N. A. Yampolsky and N. J. Fisch, Phys. Plasmas 16, 072104 (2009); D. Bénisti, D. J. Strozzi, L. Gremillet, and O. Morice, Phys. Rev. Lett. 103, 155002 (2009)] introduced to predict the nonlinear growth of stimulated Raman scattering in the kinetic regime, and providing moreover a nonlinear description of the collisionless, Landau-like, damping rate of the driven electron plasma wave. We first recall the general theoretical framework common to these two models, based on the derivation of the imaginary part of the electron susceptibility, v i , and then discuss in detail why the two approaches differ. By comparing the theoretical predictions for v i to those derived from test particle or Vlasov simulations, we moreover discuss the range of validity of the two models.

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Section: Introductionmentioning

confidence: 99%

Comparisons between nonlinear kinetic modelings of simulated Raman scattering using envelope equations

2012

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“…Other studies of thermal RBS by Vu et al, however, indicate that linear Landau damping is only part of the story. Using the reduced-PIC code 16 they observed an RBS reflectivity considerably larger than predictions based on a fixed damping coefficient, which they attributed to reduced damping by trapped particles. 21 Kinetic effects are also important in Langmuir wave breaking, where electrons begin to be trapped in the ponderomotive potential.…”

Section: Reduced Rbs Coupling In Thermal Plasmamentioning

confidence: 92%

“…Other hybrid-type codes which combine the envelope and PIC models are reduced PIC, 16 quasistatic PIC, 17 and turboWAVE. 18 The reduced-PIC code is designed to study parametric decay instabilities and the scattering of lasers in plasmas.…”

Section: Introductionmentioning

confidence: 99%

Slowly varying envelope kinetic simulations of pulse amplification by Raman backscattering

et al. 2004

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A numerical code based on an eikonal formalism has been developed to simulate laser-plasma interactions, specifically Raman backscatter (RBS). In this code, the dominant laser modes are described by their wave envelopes, avoiding the need to resolve the laser frequency; appropriately time-averaged equations describe particle motion. The code is fully kinetic, and thus includes critical physics such as particle trapping and Landau damping which are beyond the scope of the commonly used fluid three-wave equations. The dominant forces on the particles are included: the ponderomotive force resulting from the beat wave of the forward and backscattered laser fields and the self-consistent plasma electric field. The code agrees well, in the appropriate regimes, with the results from three-wave equations and particle-in-cell simulations. The effects of plasma temperature on RBS amplification are studied. It is found that increasing the plasma temperature results in modification to particle trapping and the saturation of RBS, even before the onset of Landau damping of the plasma wave. This results in a reduction in the coupling efficiency compared to predictions based on the three-wave equations.

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“…19 For this series, the electron density is varied from n e =n c ¼ 0:03 to 0.1 (n c is the critical density for which the plasma frequency and the incident pump wave frequency are equal) at two different laser intensities of I 0 ¼ 4:5 Â 10 15 and 1 Â 10 16 W/cm 2 , with the electron and ion temperatures T e ¼ 700 eV and T i ¼ 140 eV (ZT e =T i ¼ 10), and the plasma extent is 160 lm. This set of simulations employs conditions attainable at the TRIDENT laser with a Helium gas jet target (Z, the ionization state, is 2).…”

Section: Simulationsmentioning

confidence: 99%

“Bloch wave” modification of stimulated Raman by stimulated Brillouin scattering

Dodd

DuBois

et al. 2013

Physics of Plasmas

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Using the reduced-description particle-in-cell (RPIC) method, we study the coupling of backward stimulated Raman scattering (BSRS) and backward stimulated Brillouin scattering (BSBS) in regimes where the reflectivity involves the nonlinear behavior of particles trapped in the daughter plasma waves. The temporal envelope of a Langmuir wave (LW) obeys a Schrödinger equation where the potential is the periodic electron density fluctuation resulting from an ion-acoustic wave (IAW). The BSRS-driven LWs in this case have a Bloch wave structure and a modified dispersion due to the BSBS-driven spatially periodic IAW, which includes frequency band gaps at kLW∼kIAW/2∼k0 (kLW, kIAW, and k0 are the wave number of the LW, IAW, and incident pump electromagnetic wave, respectively). This band structure and the associated Bloch wave harmonic components are distinctly observed in RPIC calculations of the electron density fluctuation spectra and this structure may be observable in Thomson scatter. Bloch wave components grow up in the LW spectrum, and are not the result of isolated BSRS. Self-Thomson scattered light from these Bloch wave components can have forward scattering components. The distortion of the LW dispersion curve implies that the usual relationship connecting the frequency shift of the BSRS-scattered light and the density of origin of this light may become inaccurate. The modified LW frequency results in a time-dependent frequency shift that increases as the IAW grows, detunes the BSRS frequency matching condition, and reduces BSRS growth. A dependence of the BSRS reflectivity on the IAW Landau damping results because this damping determines the levels of IAWs. The time-dependent reflectivity in our simulations is characterized by bursts of sub-picosecond pulses of BSRS alternating with multi-ps pulses of BSBS, and BSRS is observed to decline precipitously as soon as SBS begins to grow from low levels. In strong BSBS regimes, the Bloch wave effects in BSRS are strong and temporal anti-correlation with BSRS is due to pump depletion in addition to frequency detuning. In most cases studied, BSBS suppressed the time-averaged reflectivity of BSRS compared to the levels obtained with fixed ions (and therefore no BSBS). The strong spatial modulation of the Bloch Langmuir waves appears to weaken electron trapping and thereby lowers the inflated reflectivity levels of BSRS.

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ASPEN: A Fully Kinetic, Reduced-Description Particle-in-Cell Model for Simulating Parametric Instabilities

Cited by 25 publications

References 33 publications

Comparisons between nonlinear kinetic modelings of simulated Raman scattering using envelope equations

Comparisons between nonlinear kinetic modelings of simulated Raman scattering using envelope equations

Slowly varying envelope kinetic simulations of pulse amplification by Raman backscattering

“Bloch wave” modification of stimulated Raman by stimulated Brillouin scattering

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