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We propose to amplify and compress an ultrashort Light Spring laser seed with a long Gaussian-shaped laser pump through Raman amplification. This Light Spring, which has a helical spatio-temporal intensity profile, can be built on the superposition of three distinct laser frequency components. In order to get an independent frequency amplification, two criteria are established. Besides these criteria, a non equal frequency separation is necessary to avoid resonance overlapping when three or more frequencies are involved. The independent set of equations, which describes the wave-wave interaction in a plasma, is solved numerically for two different Light Spring configurations. In both cases, the amplification and transversal compression of the seed laser pulse have been observed, with a final profile similar to that of the usual Gaussian-shaped seed pulses. In addition, two different kinds of helical plasma waves are excited., Comment: Submitted to Physics of Plasma, 10 pages, 5 figures

The contribution to the radiative transport due to collective scattering in astrophysical plasmas and a generalization of the Kompaneets equation is obtained. Both the stimulated and spontaneous scattering and the contribution of scattering on electrons and ions are taken into account and shown to be important over a broad range of frequencies ωpe

Using a quantum fluid model, a set of three paraxial coupled equations to describe the free-electron laser instability is derived. These equations are solved numerically considering Laguerre-Gaussian modes as the initial conditions to study the transfer of orbital angular momentum between them, which satisfies the total angular momentum conservation as matching condition. The amplification and compression of the output radiation is observed. Using the method of separation of variables, the set of coupled equations, which describes a π-pulse solution, is obtained in such a way that a transverse overlapping factor, R, governs the energy exchange efficiency of the process.

The scattering of electromagnetic waves from counter‐rotating vortex streets associated with nonlinear convective cells in uniform plasmas has been considered. The vortex street solution of the Navier–Stokes or the Hasegawa–Mima (and of the ‘‘sinh‐Poisson’’) equation is adopted as a scatterer. Assuming arbitrary polarization and profile function for the incident electromagnetic field, a compact expression for the scattering cross section has been obtained. Specific results for the differential cross section are obtained for the case in which the incident beam has a Gaussian profile and propagates as an ordinary mode. The results show that when the characteristic wavelength of the vortex street (λv=2π/a) is larger than that of the incident electromagnetic wave (λi=2π/ki), the differential cross section dσ/dΩ has a very well‐defined angular periodicity; in fact, it is a collection of Gaussians varying as exp[−f(kiw)2], where w is the waist and f is a function expressing a kind of ‘‘Bragg condition.’’ On the...

The influence of relativistic correction on the propagation properties of a high-frequency range of the elliptically polarized extraordinary electromagnetic (EP-X-EM) waves in the magnetized spin quantum plasma (MSQP) is investigated by a quantum magneto hydrodynamics model. In such a situation, the relativistic effect becomes particularly noticeable in the presence of a very strong external magnetic field B 0 ≥ B Q ≡ 4.4138 × 10 9 T and a highly dense plasma n 0 ≫ n Q ≃ 10 32 m − 3 where BQ and nQ are the quantum critical magnetic field strength and electron density, respectively. For comparing with a non-relativistic regime, a new dispersion relation that extends the classical EP-X-EM waves to the quantum relativistic context is derived. Furthermore, the cut-off and resonance frequencies of this type of waves are also obtained, allowing us to define the pass and stop bands where waves can propagate in the plasma. As a new result of our work, it is found that the relativistic effect can lead to reduc...

Keeping in view the kinetic treatment for plasma particles, the electrostatic twisted dust-acoustic (DA) and dust-ion-acoustic (DIA) waves are investigated in a collisionless unmagnetized multi-component dusty plasma, whose constituents are the electrons, singly ionized positive ions, and negatively charged massive dust particulates. With this background, the Vlasov–Poisson equations are coupled together to derive a generalized dielectric constant by utilizing the Laguerre-Gaussian perturbed distribution function and electrostatic potential in the paraxial limit. The dispersion and damping rates of twisted DA and DIA waves are analyzed with finite orbital angular momentum states in a multi-component dusty plasma. Significant modifications concerning the real wave frequencies and damping rates appeared with varying twisted dimensionless parameter and dust concentration. In particular, it is shown that dust concentration enhances the phase speed of the DIA waves in contrary to DA waves, whereas the impact of twisted parameter reduces the frequencies of both DA and DIA waves. The results should be useful for the understanding of particle transport and trapping phenomena caused by wave excitation in laboratory dusty plasmas.

A fully relativistic particle-in-cell code is used to simulate atomic clusterexplosions following the interaction with ultrashort high-intensity laser pulses, investigating the dynamics of a 1 μm hydrogen cluster explosion and providing information about the time-resolved position, momentum, and energy of electrons and ions, for different laser intensities. The results indicate that the mechanism responsible for cluster expansion is Coulombic explosion producing MeV ions and electrons.

A new neutrino magnetohydrodynamics (NMHD) model is formulated, where the effects of the charged weak current on the electron-ion magnetohydrodynamic fluid are taken into account. The model incorporates in a systematic way the role of the Fermi neutrino weak force in magnetized plasmas. A fast neutrino-driven short wavelengths instability associated with the magnetosonic wave is derived. Such an instability should play a central role in strongly magnetized plasma as occurs in supernovae, where dense neutrino beams also exist. In addition, in the case of nonlinear or high frequency waves, the neutrino coupling is shown to be responsible for breaking the frozen-in magnetic field lines condition even in infinite conductivity plasmas. Simplified and ideal NMHD assumptions were adopted and analyzed in detail.

It is found that an ensemble of random phase incoherent neutrinos can generate both the inhomogeneities and magnetic fields in the early universe. Hence, neutrinos can be considered as building blocks of the two most important astrophysical phenomena that are central to modern astroparticle physics and cosmology.

It is shown that a wake of electron plasma oscillations can be created by the nonlinear ponderomotive force of an intense neutrino flux. The electrons trapped in the plasma wakefield will be accelerated to high energies. Such processes may be important in supernovas and pulsars.

Photon acceleration is the phenomenon whereby a light wave changes color when propagating through a medium whose index of refraction changes in time. This concept can be used to describe the spectral changes experienced by electromagnetic waves when they propagate in spatially and temporally varying plasmas. In this paper the detection of a large-amplitude laser-driven wake field is reported for the first time, demonstrating photon acceleration. Several features characteristic of photon acceleration in wake fields, such as splitting of the main spectral peak and asymmetries between the blueshift and redshift for large shifts, have been observed. The experiment is modeled using both a novel photon-kinetic code and a three-dimensional particle-in-cell code. In addition to the wide-ranging applications in the field of compact particle accelerators, the concept of wave kinetics can be applied to understanding phenomena in nonlinear optics, space physics, and fusion energy research. © 2006 American Institute of Physics.

Reflection of an electron beam by an intense laser pulse is considered. This is the so-called photon mirror configuration for laser acceleration in vacuum, where the energy of the incident electron beam is nearly double-Doppler shifted due to reflection on the laser pulse front. A wave-electron optical description for electron reflection and resonant backscattering, due to both linear electric field force and quadratic ponderomotive force, is provided beyond the paraxial approximation. This is done by assuming that the single electron of the beam is spin-less and therefore its motion can be described by a quantum scalar field whose spatiotemporal evolution is governed by the Klein-Gordon equation (Klein-Gordon field). Our present model, not only confirms the classical results but also shows the occurrence of purely quantum effects, such as partial reflection of the incident electron beam and enhanced backscattering due to Bragg resonance.

We consider the collective neutrino plasma interactions and study the electron plasma instabilities produced by a nearly mono-energetic neutrino beam in a plasma. We describe the mutual interaction between neutrino flavor oscillations and electron plasma waves. We show that the neutrino flavor oscillations are not only perturbed by electron plasmas waves but also contribute to the dispersion relation and the growth rates of neutrino beam instabilities.

The kinetic theory of electron plasma waves with finite orbital angular momentum has recently been introduced by Mendonca. This model shows possibility of new kind of plasma waves and instabilities. We have extended the theory to ion-acoustic plasma vortices carrying orbital angular momentum. The dispersion equation is derived under paraxial approximation which exhibits a kind of linear vortices and their Landau damping. The numerical solutions are obtained and compared with analytical results which are in good agreement. The physical interpretation of the ion-acoustic plasma vortices and their Landau resonance conditions are given for typical case of Maxwellian plasmas.

We describe the kinetic theory of electron plasma waves with orbital angular momentum or twisted plasmons. The conditions for a twisted Landau resonance to exist are established, and this concept is introduced for the first time. Expressions for the kinetic dispersion relation and for the electron Landau damping are derived. The particular case of a Maxwellian plasma is examined in detail. The new contributions to wave dispersion and damping due the orbital angular momentum are discussed. It is shown that twisted plasmons can be excited by rotating electron beams.

A quantum kinetic equation, valid for relativistic unmagnetized plasmas, is derived here. This equation describes the evolution of a quantum quasi-distribution, which is the Wigner function for relativistic spinless charged particles in a plasma, and it is exactly equivalent to a Klein-Gordon equation. Our quantum kinetic equation reduces to the Vlasov equation in the classical limit, where the Wigner function is replaced by a classical distribution function. An approximate form of the quantum kinetic equation is also derived, which includes first order quantum corrections. This is applied to electron plasma waves, for which a new dispersion relation is obtained. It is shown that quantum recoil effects contribute to the electron Landau damping with a third order derivative term. The case of high frequency electromagnetic waves is also considered. Its dispersion relation is shown to be insensitive to quantum recoil effects for equilibrium plasma distributions.

Electron plasma waves carrying orbital angular momentum are investigated in an unmagnetized collisionless plasma composed of inertial electrons and static ions. For this purpose, the usual plasmon dispersion relation is employed to derive an approximate paraxial equation. The latter is analyzed with a Gaussian beam solution. For a finite angular momentum associated with the plasmon, Laguerre–Gaussian (LG) solutions are employed for solving the electrostatic potential problem which gives approximate solution and is valid for plasmon beams in the paraxial approximation. The LG potential determines the electric field components and energy flux of plasmons with finite angular momentum. Numerical illustrations show that the radial and angular mode numbers strongly modify the profiles of the LG potential.

Nonlinear wave-driven processes in plasmas are normally described by either a monochromatic pump wave that couples to other monochromatic waves, or as a random phase wave coupling to other random phase waves. An alternative approach involves a random or broadband pump coupling to monochromatic and/or coherent structures in the plasma. This approach can be implemented through the wave-kinetic model. In this model, the incoming pump wave is described by either a bunch (for coherent waves) or a sea (for random phase waves) of quasi-particles. This approach has been applied to both photon acceleration in laser wakefields and drift wave turbulence in magnetized plasma edge configurations. Numerical simulations have been compared to experiments, varying from photon acceleration to drift mode-zonal flow turbulence, and good qualitative correspondences have been found in all cases.

Explicit expressions for the induced electric charge of photons in magnetized plasmas are derived. The electric charges arise due to the electric fields that are created by the photon pressure.

A wave kinetic equation equivalent to the Schrodinger-like equation for the electrons is derived from relativistic theory in the eikonal approximation. This equation is used to study the interaction of the relativistic electron beam in a wiggler field in the quantum regime, i.e., when the normalized quantum free-electron laser parameter ρ¯⩽1. A general quantum dispersion relation and an expression for free-electron laser instabilities are derived. Conditions for kinetic instability, which takes into account the Landau damping effect, are established.

Original article: Physics of Plasmas 13, 033108 (2006) References to the technique employed to determine the numerical Wigner transform were missing, which are presented here for the sake of completeness. The numerical Wigner transform presented in Fig. 4 was calculated using the MATLAB HOSA Toolbox,1 employing the analytic signal. The different numerical approaches to evaluate the Wigner transform are discussed in detail by Bizarro et al.2 Some of the authors (F. F. and L. O. S.) acknowledge discussions with A. Figueiredo and J. P. S. Bizarro regarding some of the properties of the discrete Wigner transform.

Recently, magnetic fields of 0.7 (±0.1) gigaGauss (GG) have been observed in the laboratory in laser plasma interactions. From scaling arguments, it appears that a few gigaGauss magnetic fields may be within reach of existing petawatt lasers. In this paper, the equations of state (EOS) are calculated in the presence of these very large magnetic fields. The appropriate domain for electron degeneracy and for Landau quantization is calculated for the density-temperature domain relevant to laser plasma interactions. The conditions for a strong Landau quantization, for a magnetic field in the domain of 1-10 GG, are obtained. The role of this paper is to formulate the EOS in terms of those that can potentially be realized in laboratory plasmas. By doing so, it is intended to alert the experimental laser-plasma physics community to the potential of realizing Landau quantization in the laboratory for the first time since the theory was first formulated. © 2005 American Institute of Physics.