Ignition Conditions for Simulated Fuel Pellets in Degenerate Plasma

A high-density, low-temperature plasma can be obtained during the compression phase in inertial confinement fusion. When high density and low temperature are reached in the plasma in the fast ignition approach, the plasma electrons can be degenerate. The electronic stopping of a slow ion is smaller than that given by the classical formula, because some transitions between the electron states are forbidden. In this case, bremsstrahlung emission is strongly sup- pressed and the ignition temperature becomes lower than that in classical plasma. The equations that predict the behavior of these plasmas are different from the classical ones, and this is the main factor in the process of decreasing the ignition temperature of the plasma. In this work, physical conditions of ignition are studied by calculating the effect of radiation loss on the ignition temperature for a simulated fuel pellet, （D/Tx/3Hey）, in degenerate plasma. In fast ignition, the energy needed for obtaining high densities is minimized and the gain can be increased considerably.

Interactions of ion acoustic multi-soliton and rogue wave with Bohm quantum potential in degenerate plasma

This work investigates the interactions among solitons and their consequences in the production of rogue waves in an unmagnetized plasmas composing non-relativistic as well as relativistic degenerate electrons and positrons, and inertial non-relativistic helium ions. The extended Poincare′–Lighthill–Kuo（PLK） method is employed to derive the two-sided Korteweg–de Vries（KdV） equations with their corresponding phase shifts. The nonlinear Schrodinger equation（NLSE） is obtained from the modified Kd V（mKdV） equation, which allows one to study the properties of the rogue waves. It is found that the Fermi temperature and quantum mechanical effects become pronounced due to the quantum diffraction of electrons and positrons in the plasmas. The densities and temperatures of the helium ions, degenerate electrons and positrons, and quantum parameters strongly modify the electrostatic ion acoustic resonances and their corresponding phase shifts due to the interactions among solitons and produce rogue waves in the plasma.

Effect of Bohm quantum potential in the propagation of ion–acoustic waves in degenerate plasmas

A theoretical investigation has been carried out on the propagation of the ion–acoustic(IA) waves in a relativistic degenerate plasma containing relativistic degenerate electron and positron fluids in the presence of inertial non-relativistic light ion fluid. The Korteweg-de Vries(K-dV), modified K-dV(m K-dV), and mixed m K-dV(mm K-dV) equations are derived by adopting the reductive perturbation method. In order to analyze the basic features(phase speed, amplitude, width,etc.) of the IA solitary waves(SWs), the SWs solutions of the K-dV, m K-dV, and mm K-d V are numerically analyzed. It is found that the degenerate pressure, inclusion of the new phenomena like the Fermi temperatures and quantum mechanical effects(arising due to the quantum diffraction) of both electrons and positrons, number densities, etc., of the plasma species remarkably change the basic characteristics of the IA SWs which are found to be formed either with positive or negative potential. The implication of our results in explaining different nonlinear phenomena in astrophysical compact objects, e.g.,white dwarfs, neutron stars, etc., and laboratory plasmas like intense laser–solid matter interaction experiments, etc., are mentioned.

Dust-Lower-Hybrid Surface Waves in Classical and Degenerate Plasmas

The dispersion relation for general dust low frequency electrostatic surface waves propagating on an interface between a magnetized dusty plasma region and a vacuum is derived by using specular reflection boundary conditions both in classical and quantum regimes. The frequency limit ω ≤ωei ≤ ωce is considered and the dispersion relation for the Dust-Lower-Hybrid Surface Waves （DLHSW＇s） is derived for both classical and quantum plasma half-space and analyzed numerically. It is shown that the wave behavior changes as the quantum nature of the problem is considered.

Shocks and Solitons in Ultradense Degenerate Electron-Positron-Ion Plasmas

The formation and propagation of shocks and solitons are investigated in an unmagnetized, ultradense plasma containing degenerate Fermi gas of electrons and positrons, and classical ion gas by employing Thomas-Fermi model. For this purpose, a deformed Korteweg-de Vries-Berger （dKdVB） equation is derived using the reductive perturbative technique for cold, adiabatic, and isothermal ions. Localized analytical solutions of dKdVB equation in planar geometry are obtained for dispersion as well as dissipation dominant cases. For nonplanar （cylindrical and spherical） geometry, time varying numerical shock wave solution of dKdVB equation is found. Its dispersion dominant case leading to the soliton solution is also discussed. The effect of ion temperature, positron concentration and dissipation is found significant on these nonlinear structures. The relevance of the results to the systems of scientific interest is pointed out.

Study of the O-mode in a relativistic degenerate electron plasma

Using the linearized relativistic Vlasov-Maxwell equations,a generalized expression for the plasma conductivity tensor is derived.The dispersion relation for the O-mode in a relativistic degenerate electron plasma is investigated by employing the Fermi-Dirac distribution function.The propagation characteristics of the O-mode（cut offs,resonances,propagation regimes,harmonic structure） are examined by using specific values of the density and the magnetic field that correspond to different relativistic dense environments.Further,it is observed that due to the relativistic effects the cut off and the resonance points are shifted to low frequency values,as a result the propagation regime is reduced.The dispersion relations for the non-relativistic and the ultra-relativistic limits are also presented.

Solitary kinetic Alfvén waves in a dense electron–positron–ion plasma with degenerate electrons and positrons

Through the use of a reductive perturbation technique, solitary kinetic Alfvén waves（KAWs） are investigated in a low but finite b（particle-to-magnetic pressure ratio） dense electron–positron–ion plasma where electrons and positrons are degenerate. The degenerate plasma model considered here permits the existence of sub-Alfvénic compressive solitary KAWs. The influence of r（equilibrium positron-to-ion density ratio）, sF（electron-to-positron Fermi temperature ratio）, b and obliqueness parameter lzon various characteristics of solitary KAWs are examined through numerical plots. We have shown that there exists a critical value of lzat which a soliton width attains its maximum value which decreases with an increase in r and sF.It is also found that solitons with a higher energy propagate more obliquely in the direction of an ambient magnetic field. The results of the present investigation may be useful for understanding low frequency nonlinear electromagnetic wave propagation in magnetized electron–positron–ion plasmas in dense stars. Specifically, the relevance of our investigation to a pulsar magnetosphere is emphasized.

Positron-Acoustic Shock Waves in a Degenerate Multi-Component Plasma

A theoretical investigation on the propagation of positron-acoustic shock waves （PASWs） in an unmagnetized, collisionless, dense plasma （containing non-relativistic inertial cold positrons, non-relativistic or ultra-relativistic degenerate electron and hot positron fluids and nondegenerate positively charged immobile ions） is carried out by employing the reductive perturbation method. The Burgers equation and its stationary shock wave solution are derived and numerically analyzed. It is observed that the relativistic effect （i.e., the presence of non/ultra- relativistic electrons and positrons） and the plasma particle number densities play vital roles in the propagation of PASWs. The implications of our results in space and interstellar compact objects including non-rotating white dwarfs, neutron stars, etc. are briefly discussed.

Coherent nonlinear structures in dense electron positron plasma

It is shown that rarefactive-type double layer structures exist in ultradense electron-positron plasma.For this purpose,an extended Korteweg de Vries equation is derived and solved analytically in the low amplitude limit by employing the appropriate fluid equations.A strong influence of quantum degeneracy pressure of electrons and positrons,quantum diffraction effects and concentration of background positive ions on double layer is noticed.It is also pointed out that the amplitude and steepness of the double layer increases with an increase in ion concentration or ion charge number.The results are examined numerically for some interesting cases of dense plasmas with illustrations.

Parallel propagating modes and anomalous spatial damping in the ultra-relativistic electron plasma with arbitrary degeneracy

The dispersion relations of parallel propagating modes（Langmuir mode, right and left handed circular polarized waves） in the weak magnetic field limit ｜ω-k·v｜ 〉〉 ？ are considered for ultra-relativistic arbitrary degenerate electron plasma. The results are presented in terms of moments of Fermi-Dirac distribution. The increase in the electron equilibrium number density from negative large（weakly degenerate） to positive large（highly degenerate） values of μ/Te is observed（where μ is the electron chemical potential and Te is the electron thermal energy）. As a result, shifting of the cutoff points in all the real dispersion branches towards the higher values and increasing in the band gap between unmagnetized longitudinal and transverse modes in k-space are examined. Also, the suppression of the weak magnetic field effects in weakly magnetized right handed and left handed circular polarized waves and a decrease in the longitudinal and transverse screening effects are observed in the graphical patterns due to an increase in the equilibrium number density.

Nonplanar Electrostatic Solitary Waves in a Relativistic Degenerate Dense Plasma

By employing the reductive perturbation technique, the propagation of cylindrical and spherical ion acoustic solitary waves is studied in an unmagnetized dense relativistic plasma, consisting of relativistically degenerate electrons and cold fluid ions. A modified Korteweg-de-Vries equation is derived and its numerical solutions have been analyzed to identify the basic features of electrostatic solitary structures that may form in such a degenerate Fermi plasma. Different degrees of relativistic electron degeneracy are discussed and compared. It is found that increasing number density leads to decrease the aznplitude the width of the ion acoustic solitary wave in both the cylindrical and spherical geometries. The relevance of the work to the compact astrophysical objects, particularly white dwarfs is pointed out.

Linear Analysis of Obliquely Propagating Longitudinal Waves in Partially Spin Polarized Degenerate Magnetized Plasma

Linear analysis of low frequency obliquely propagating electrostatic waves in a partially spin polarized degenerate magnetized plasma is presented. Using Fourier analysis, a general linear dispersion relation is derived for low frequency electrostatic lower hybrid(LH) wave, ion acoustic(IA) wave and ion cyclotron(IC) wave in the presence of electron spin polarization. It is found that the electron spin polarization gives birth to a new spin-dependent wave(spin electron acoustic wave) in the spectrum of these waves. Further, the electron spin polarization also causes drastic shifts in the frequency spectrum of these waves. These effects would have a strong bearing on wave phenomena in degenerate astrophysical plasmas.

Fusion Energy and Stopping Power in a Degenerate DT Pellet Driven by a Laser-Accelerated Proton Beam

In this paper, we have improved the fast ignition scheme in order to have more authority needed for highenergy-gain. Due to the more penetrability and energy deposition of the particle beams in fusion targets, we employ a laser-to-ion converter foil as a scheme for generating energetic ion beams to ignite the fusion fuel. We find the favorable intensity and wavelength of incident laser by evaluating the laser-proton conversion gain. By calculating the source-target distance, proton beam power and energy are estimated. Our analysis is generalized to the plasma degeneracy effects which can increase the fusion gain several orders of magnitude by decreasing the ion-electron collisions in the plasma.It is found that the wavelength of 0.53 μm and the intensity of about 1020W/cm^2, by saving about 10% conversion coefficient, are the suitable measured values for converting a laser into protons. Besides, stopping power and fusion burn calculations have been done in degenerate and non-degenerate plasma mediums. The results indicate that in the presence of degeneracy, the rate of fusion enhances.