scholarly journals Nonlinear Electron Acoustic Waves in Dissipative Plasma with Superthermal Electrons

2016 ◽  
Vol 8 (1) ◽  
pp. 64 ◽  
Author(s):  
A. M. El-Hanbaly ◽  
E. K. El-Shewy ◽  
A. I. Kassem ◽  
H. F. Darweesh
Keyword(s):  
Shock Waves ◽  
Acoustic Waves ◽  
Inertial Confinement Fusion ◽  
Collisionless Plasma ◽  
Homogeneous System ◽  
Travelling Wave ◽  
Reductive Perturbation Method ◽  
Inertial Confinement ◽  
Plasma Parameters ◽  
Electron Acoustic

The nonlinear properties of small amplitude electron-acoustic ( EA) solitary and shock waves in a homogeneous system of unmagnetized collisionless plasma consisted of a cold electron fluid and superthermal hot electrons obeying superthermal distribution, and stationary ions have been investigated. A reductive perturbation method was employed to obtain the Kadomstev-Petviashvili-Burgers (KP-Brugers) equation. Some solutions of physical interest are obtained. These solutions are related to soliton, monotonic and oscillatory shock waves and their behaviour are shown graphically. The formation of these solutions depends crucially on the value of the Burgers term and the plasma parameters as well. By using the tangent hyperbolic (tanh) method, another interesting type of solution which is a combination between shock and soliton waves is obtained . The topology of phase portrait and potential diagram of the KP-Brugers equation is investigated.The advantage of using this method is that one can predict different classes of the travelling wave solutions according to different phase orbits. The obtained results may be helpful in better understanding of waves propagation in various space plasma environments as well as in inertial confinement fusion laboratory plasmas.

Dust acoustic shock waves in dusty plasma of opposite polarity with non-extensive electron and ion distributions

2014 ◽  
Vol 80 (3) ◽  
pp. 517-528 ◽  
Author(s):  
S. K. Zaghbeer ◽  
H. H. Salah ◽  
N. H. Sheta ◽  
E. K. El-Shewy ◽  
A. Elgarayhi
Keyword(s):  
Shock Waves ◽  
Dusty Plasma ◽  
Collisionless Plasma ◽  
Homogeneous System ◽  
Opposite Polarity ◽  
Reductive Perturbation Method ◽  
Ion Distributions ◽  
Electrons And Ions ◽  
Dust Acoustic ◽  
Space Environments

A theoretical investigation has been made of obliquely propagating nonlinear electrostatic shock structures. The reductive perturbation method has been used to derive the Korteweg-de Vries-Burger (KdV-Burger) equation for dust acoustic shock waves in a homogeneous system of a magnetized collisionless plasma comprising a four-component dusty plasma with massive, micron-sized, positively, negatively dust grains and non-extensive electrons and ions. The effect of dust viscosity coefficients of charged dusty plasma of opposite polarity and the non-extensive parameters of electrons and ions have been studied. The behavior of the oscillatory and monotonic shock waves in dusty plasma has been investigated. It has been found that the presence of non-extensive parameters significantly modified the basic properties of shock structures in space environments.

scholarly journals Electrostatic shock properties inferred from AKR fine structure

2003 ◽  
Vol 10 (1/2) ◽  
pp. 87-92 ◽  
Author(s):  
R. Pottelette ◽  
R. A. Treumann ◽  
M. Berthomier ◽  
J. Jasperse
Keyword(s):  
Electric Fields ◽  
Acoustic Waves ◽  
Sagdeev Potential ◽  
Plasma Parameters ◽  
Fluid Approximation ◽  
Auroral Kilometric Radiation ◽  
Ion Acoustic ◽  
Electron Holes ◽  
Spectral Frequency ◽  
Electron Acoustic

Abstract. The auroral kilometric radiation (AKR) consists of a large number of fast drifting elementary radiation events that have been interpreted as travelling electron holes resulting from the nonlinear evolution of electron-acoustic waves. The elementary radiation structures sometimes become reflected or trapped in slowly drifting larger structures where the parallel electric fields are located. These latter features have spectral frequency drifts which can be interpreted in terms of the propagation of shock-like disturbances along the auroral field line at velocities near the ion-acoustic speed. The amplitude, speed, and shock width of such localized ion-acoustic shocks are determined here in the fluid approximation from the Sagdeev potential, assuming realistic plasma parameters. It is emphasized that the electrostatic potentials of such nonlinear structures contribute to auroral acceleration.

scholarly journals Collective absorption of laser radiation in plasma at sub-relativistic intensities

2019 ◽  
Vol 7 ◽  
Author(s):  
Y. J. Gu ◽  
O. Klimo ◽  
Ph. Nicolaï ◽  
S. Shekhanov ◽  
S. Weber ◽  
...  
Keyword(s):  
Inertial Confinement Fusion ◽  
Stimulated Raman Scattering ◽  
Laser Energy ◽  
Brillouin Scattering ◽  
Critical Density ◽  
Plasma Waves ◽  
High Amplitude ◽  
Inertial Confinement ◽  
Hot Electron ◽  
Plasma Parameters

Processes of laser energy absorption and electron heating in an expanding plasma in the range of irradiances $I\unicode[STIX]{x1D706}^{2}=10^{15}{-}10^{16}~\text{W}\,\cdot \,\unicode[STIX]{x03BC}\text{m}^{2}/\text{cm}^{2}$ are studied with the aid of kinetic simulations. The results show a strong reflection due to stimulated Brillouin scattering and a significant collisionless absorption related to stimulated Raman scattering near and below the quarter critical density. Also presented are parametric decay instability and resonant excitation of plasma waves near the critical density. All these processes result in the excitation of high-amplitude electron plasma waves and electron acceleration. The spectrum of scattered radiation is significantly modified by secondary parametric processes, which provide information on the spatial localization of nonlinear absorption and hot electron characteristics. The considered domain of laser and plasma parameters is relevant for the shock ignition scheme of inertial confinement fusion.

scholarly journals Collision-less shocks and solitons in dense laser-produced Fermi plasma

2020 ◽  
Vol 38 (1) ◽  
pp. 25-38
Author(s):  
J. Goswami ◽  
S. Chandra ◽  
J. Sarkar ◽  
S. Chaudhuri ◽  
B. Ghosh
Keyword(s):  
Acoustic Waves ◽  
Perturbation Technique ◽  
Reductive Perturbation Method ◽  
Viscous Force ◽  
Quantum Plasma ◽  
Linear Dispersion ◽  
Laser Plasma Interaction ◽  
Reductive Perturbation ◽  
Solitary Structures ◽  
Electron Acoustic

AbstractThe theoretical investigation of shocks and solitary structures in a dense quantum plasma containing electrons at finite temperature, nondegenerate cold electrons, and stationary ions has been carried out. A linear dispersion relation is derived for the corresponding electron acoustic waves. The solitary structures of small nonlinearity have been studied by using the standard reductive perturbation method. We have considered collisions to be absent, and the shocks arise out of viscous force. Furthermore, with the help of a standard reductive perturbation technique, a KdV–Burger equation has been derived and analyzed numerically. Under limiting cases, we have also obtained the KdV solitary profiles and studied the parametric dependence. The results are important in explaining the many phenomena of the laser–plasma interaction of dense plasma showing quantum effects.

Radiation and electron thermal conduction damping of acoustic perturbations in igniting deuterium–tritium gas

2019 ◽  
Vol 85 (6) ◽  
Author(s):  
Conner D. Galloway ◽  
Robert O. Hunter ◽  
Alexander V. Valys ◽  
Gene H. McCall
Keyword(s):  
Dispersion Relation ◽  
Acoustic Waves ◽  
Thermal Conduction ◽  
Inertial Confinement Fusion ◽  
Equilibrium Configuration ◽  
Areal Density ◽  
Inertial Confinement ◽  
Confinement Fusion ◽  
Electron Thermal Conduction ◽  
Low Order

We derive a dispersion relation for the damping of acoustic waves in equi-molar deuterium–tritium (DT) gas due to radiation coupling and electron thermal conduction and discuss its significance for inertial confinement fusion (ICF) targets with high-Z shells surrounding a central DT fuel region. As the shell implodes around DT fuel in such a target, shocks and waves are transmitted through the DT gas. If the shell is perturbed due to drive non-uniformity or manufacturing imperfection, these shocks and waves may be perturbed as well, and can potentially re-perturb the shell. This can complicate calculation of shell stability and implosion asymmetry and in general make the target less robust against implosion non-uniformity. Damping of perturbations in DT gas can alleviate these complications. Also, damping of low-order modes, which is primarily due to radiation coupling, can drive the DT gas to an isobaric and isothermal ‘equilibrium’ configuration during ignition. We find that for the range of common ignition temperatures in targets with high-Z shells, $2.5\lesssim T_{ig}\lesssim 3.5$  keV, damping of low-order modes is significant for areal densities ( $\unicode[STIX]{x1D70C}r$ ) in the broad range of $0.6\lesssim \unicode[STIX]{x1D70C}r\lesssim 1.8~\text{g}~\text{cm}^{-2}$ . This suggests it is advantageous to design these targets to achieve areal densities at ignition within this range. Furthermore, we derive a simple constraint between areal density and temperature, $\unicode[STIX]{x1D70C}r=0.34T_{o}$ where $T_{o}$ is in keV, such that DT gas undergoing equilibrium ignition is optimally robust against non-uniformity.

scholarly journals Generation of shock waves in dense plasmas by high-intensity laser pulses

Nukleonika ◽  
2015 ◽  
Vol 60 (2) ◽  
pp. 193-198 ◽  
Author(s):  
John Pasley ◽  
I. A. Bush ◽  
Alexander P. L. Robinson ◽  
P. P. Rajeev ◽  
S. Mondal ◽  
...  
Keyword(s):  
Shock Waves ◽  
Laser Plasma ◽  
Inertial Confinement Fusion ◽  
Laser Pulses ◽  
Fast Ignition ◽  
Intense Laser ◽  
Inertial Confinement ◽  
Relative Significance ◽  
Wide Range ◽  
Confinement Fusion

Abstract When intense short-pulse laser beams (I > 1022 W/m2, τ < 20 ps) interact with high density plasmas, strong shock waves are launched. These shock waves may be generated by a range of processes, and the relative significance of the various mechanisms driving the formation of these shock waves is not well understood. It is challenging to obtain experimental data on shock waves near the focus of such intense laser–plasma interactions. The hydrodynamics of such interactions is, however, of great importance to fast ignition based inertial confinement fusion schemes as it places limits upon the time available for depositing energy in the compressed fuel, and thereby directly affects the laser requirements. In this manuscript we present the results of magnetohydrodynamic simulations showing the formation of shock waves under such conditions, driven by the j × B force and the thermal pressure gradient (where j is the current density and B the magnetic field strength). The time it takes for shock waves to form is evaluated over a wide range of material and current densities. It is shown that the formation of intense relativistic electron current driven shock waves and other related hydrodynamic phenomena may be expected over time scales of relevance to intense laser–plasma experiments and the fast ignition approach to inertial confinement fusion. A newly emerging technique for studying such interactions is also discussed. This approach is based upon Doppler spectroscopy and offers promise for investigating early time shock wave hydrodynamics launched by intense laser pulses.

scholarly journals Electron-Acoustic (Un)Modulated Structures in a Plasma Having (r, q)-Distributed Electrons: Solitons, Super Rogue Waves, and Breathers

Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2029
Author(s):  
Wedad Albalawi ◽  
Rabia Jahangir ◽  
Waqas Masood ◽  
Sadah A. Alkhateeb ◽  
Samir A. El-Tantawy
Keyword(s):  
Acoustic Waves ◽  
Rogue Waves ◽  
Distribution Functions ◽  
Sagdeev Potential ◽  
Plasma Parameters ◽  
Positive Ions ◽  
Modulated Structures ◽  
Existence Domain ◽  
Unmagnetized Plasma ◽  
Electron Acoustic

The propagation of electron-acoustic waves (EAWs) in an unmagnetized plasma, comprising (r,q)-distributed hot electrons, cold inertial electrons, and stationary positive ions, is investigated. Both the unmodulated and modulated EAWs, such as solitary waves, rogue waves (RWs), and breathers are discussed. The Sagdeev potential approach is employed to determine the existence domain of electron acoustic solitary structures and study the perfectly symmetric planar nonlinear unmodulated structures. Moreover, the nonlinear Schrödinger equation (NLSE) is derived and its modulated solutions, including first order RWs (Peregrine soliton), higher-order RWs (super RWs), and breathers (Akhmediev breathers and Kuznetsov–Ma soliton) are presented. The effects of plasma parameters and, in particular, the effects of spectral indices r and q, of distribution functions on the characteristics of both unmodulated and modulated EAWs, are examined in detail. In a limited cases, the (r,q) distribution is compared with Maxwellian and kappa distributions. The present investigation may be beneficial to comprehend and predict the modulated and unmodulated electron acoustic structures in laboratory and space plasmas.

Effect of q-nonextensive distribution of electrons on dust acoustic shock waves in strongly coupled dusty plasmas

2011 ◽  
Vol 89 (10) ◽  
pp. 1073-1078 ◽  
Author(s):  
Hamid Reza Pakzad
Keyword(s):  
Shock Waves ◽  
Acoustic Waves ◽  
Burgers Equation ◽  
Dusty Plasmas ◽  
Reductive Perturbation Method ◽  
Nonlinear Propagation ◽  
Nonextensive Electrons ◽  
Strongly Coupled ◽  
Dust Acoustic ◽  
Nonextensive Distribution

The reductive perturbation method is used to derive the Kordeweg – de Vries – Burgers equation in strongly coupled dusty plasmas containing Boltzmann distributed ions and q-nonextensive electrons. It is observed that the nonlinear propagation of the dust acoustic waves gives rise to shock structures when there is strong correlation among the dust grains. The effect of the q-nonextensive parameter on the shock waves is discussed.

A hydrodynamic analysis of self-similar radiative ablation flows

2018 ◽  
Vol 848 ◽  
pp. 219-255
Author(s):  
J.-M. Clarisse ◽  
J.-L. Pfister ◽  
S. Gauthier ◽  
C. Boudesocque-Dubois
Keyword(s):  
Acoustic Waves ◽  
Inertial Confinement Fusion ◽  
High Energy ◽  
High Energy Density ◽  
Inertial Confinement ◽  
X Rays ◽  
Nonlinear Conductivity ◽  
Conduction Model ◽  
Hydrodynamic Analysis ◽  
Self Similar

Self-similar solutions to the compressible Euler equations with nonlinear conduction are considered as particular instances of unsteady radiative deflagration – or ‘ablation’ – waves with the goal of characterizing the actual hydrodynamic properties that such flows may present. The chosen family of solutions, corresponding to the ablation of an initially quiescent perfectly cold and homogeneous semi-infinite slab of inviscid compressible gas under the action of increasing external pressures and radiation fluxes, is well suited to the description of the early ablation of a target by gas-filled cavity X-rays in experiments of high energy density physics. These solutions are presently computed by means of a highly accurate numerical method for the radiative conduction model of a fully ionized plasma under the approximation of a non-isothermal leading shock wave. The resulting set of solutions is unique for its high fidelity description of the flows down to their finest scales and its extensive exploration of external pressure and radiative flux ranges. Two different dimensionless formulations of the equations of motion are put forth, yielding two classifications of these solutions which are used for carrying out a quantitative hydrodynamic analysis of the corresponding flows. Based on the main flow characteristic lengths and on standard characteristic numbers (Mach, Péclet, stratification and Froude numbers), this analysis points out the compressibility and inhomogeneity of the present ablative waves. This compressibility is further analysed to be too high, whether in terms of flow speed or stratification, for the low Mach number approximation, often used in hydrodynamic stability analyses of ablation fronts in inertial confinement fusion (ICF), to be relevant for describing these waves, and more specifically those with fast expansions which are of interest in ICF. Temperature stratification is also shown to induce, through the nonlinear conductivity, supersonic upstream propagation of heat-flux waves, besides a modified propagation of quasi-isothermal acoustic waves, in the flow conduction regions. This description significantly departs from the commonly admitted depiction of a quasi-isothermal conduction region where wave propagation is exclusively ascribed to isothermal acoustics and temperature fluctuations are only diffused.

scholarly journals Raman–Brillouin interplay for inertial confinement fusion relevant laser–plasma interaction

2016 ◽  
Vol 4 ◽  
Author(s):  
C. Riconda ◽  
S. Weber
Keyword(s):  
Raman Scattering ◽  
Acoustic Waves ◽  
Inertial Confinement Fusion ◽  
Clear Correlation ◽  
Inertial Confinement ◽  
Decay Instability ◽  
Wide Range ◽  
Confinement Fusion ◽  
Parameter Ranges ◽  
Langmuir Decay

The co-existence of the Raman and Brillouin backscattering instability is an important issue for inertial confinement fusion. The present paper presents extensive one-dimensional (1D) particle-in-cell (PIC) simulations for a wide range of parameters extending and complementing previous findings. PIC simulations show that the scenario of reflectivity evolution and saturation is very sensitive to the temperatures, intensities, size of plasma and boundary conditions employed. The Langmuir decay instability is observed for rather small $k_{epw}{\it\lambda}_{D}$ but has no influence on the saturation of Brillouin backscattering, although there is a clear correlation of Langmuir decay instability modes and ion-fractional decay for certain parameter ranges. Raman backscattering appears at any intensity and temperature but is only a transient phenomenon. In several configurations forward as well as backward Raman scattering is observed. For the intensities considered, $I{\it\lambda}_{o}^{2}$ above $10^{15}~\text{W}~{\rm\mu}\text{m}^{2}/\text{cm}^{2}$ , Raman is always of bursty nature. A particular setup allows the simulation of multi-speckle aspects in which case it is found that Raman is self-limiting due to strong modifications of the distribution function. Kinetic effects are of prime importance for Raman backscattering at high temperatures. No unique scenario for the saturation of Raman scattering or Raman–Brillouin competition does exist. The main effect in the considered parameter range is pump depletion because of large Brillouin backscattering. However, in the low $k_{epw}{\it\lambda}_{D}$ regime the presence of ion-acoustic waves due to the Langmuir decay instability from the Raman created electron plasma waves can seed the ion-fractional decay and affect the Brillouin saturation.

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