798 research outputs found
A linearized kinetic theory of spin-1/2 particles in magnetized plasmas
We have considered linear kinetic theory including the electron spin
properties in a magnetized plasma. The starting point is a mean field
Vlasov-like equation, derived from a fully quantum mechanical treatment, where
effects from the electron spin precession and the magnetic dipole force is
taken into account. The general conductivity tensor is derived, including both
the free current contribution, as well as the magnetization current associated
with the spin contribution. We conclude the paper with an extensive discussion
of the quantum-mechanical boundary where we list parameter conditions that must
be satisfied for various quantum effects to be influential.Comment: 11 page
Nonlinear coupled Alfv\'{e}n and gravitational waves
In this paper we consider nonlinear interaction between gravitational and
electromagnetic waves in a strongly magnetized plasma. More specifically, we
investigate the propagation of gravitational waves with the direction of
propagation perpendicular to a background magnetic field, and the coupling to
compressional Alfv\'{e}n waves. The gravitational waves are considered in the
high frequency limit and the plasma is modelled by a multifluid description. We
make a self-consistent, weakly nonlinear analysis of the Einstein-Maxwell
system and derive a wave equation for the coupled gravitational and
electromagnetic wave modes. A WKB-approximation is then applied and as a result
we obtain the nonlinear Schr\"{o}dinger equation for the slowly varying wave
amplitudes. The analysis is extended to 3D wave pulses, and we discuss the
applications to radiation generated from pulsar binary mergers. It turns out
that the electromagnetic radiation from a binary merger should experience a
focusing effect, that in principle could be detected.Comment: 20 pages, revtex4, accepted in PR
Nonlinear Interactions Between Gravitational Radiation and Modified Alfven Modes in Astrophysical Dusty Plasmas
We present an investigation of nonlinear interactions between Gravitational
Radiation and modified Alfv\'{e}n modes in astrophysical dusty plasmas.
Assuming that stationary charged dust grains form neutralizing background in an
electron-ion-dust plasma, we obtain the three wave coupling coefficients, and
calculate the growth rates for parametrically coupled gravitational radiation
and modified Alfv\'{e}n-Rao modes. The threshold value of the gravitational
wave amplitude associated with convective stabilization is particularly small
if the gravitational frequency is close to twice the modified Alfv\'en
wave-frequency. The implication of our results to astrophysical dusty plasmas
is discussed.Comment: A few typos corrected. Published in Phys. Rev.
New Quantum Limits in Plasmonic Devices
Surface plasmon polaritons (SPPs) have recently been recognized as an
important future technique for microelectronics. Such SPPs have been studied
using classical theory. However, current state-of-the-art experiments are
rapidly approaching nanoscales, and quantum effects can then become important.
Here we study the properties of quantum SPPs at the interface between an
electron quantum plasma and a dielectric material. It is shown that the effect
of quantum broadening of the transition layer is most important. In particular,
the damping of SPPs does not vanish even in the absence of collisional
dissipation, thus posing a fundamental size limit for plasmonic devices.
Consequences and applications of our results are pointed out.Comment: 5 pages, 2 figures, to appear in Europhysics Letter
Fast Magnetosonic Waves Driven by Gravitational Waves
The propagation of a gravitational wave (GW) through a magnetized plasma is
considered. In particular, we study the excitation of fast magnetosonic waves
(MSW) by a gravitational wave, using the linearized general-relativistic
hydromagnetic equations. We derive the dispersion relation for the plasma,
treating the gravitational wave as a perturbation in a Minkowski background
space-time. We show that the presence of gravitational waves will drive
magnetosonic waves in the plasma and discuss the potential astrophysical
implications.Comment: 12 pages, 2 figures, Astronomy and Astrophysics in pres
Photon-graviton pair conversion
We consider the conversion of gravitons and photons as a four-wave mixing
process. A nonlinear coupled systems of equations involving two gravitons and
two photons is obtained, and the energy exchange between the different degrees
of freedom is found. The scattering amplitudes are obtained, from which a
crossection for incoherent processes can be found. An analytical example is
given, and applications to the early Universe are discussed.Comment: 5 pages, slightly modified as compared to v1, to appear in Class.
Quantum Grav. as a Letter to the Edito
Ferroplasmas: Magnetic Dust Dynamics in a Conducting Fluid
We consider a dusty plasma, in which the dust particles have a magnetic
dipole moment. A Hall-MHD type of model, generalized to account for the
intrinsic magnetization, is derived. The model is shown to be energy
conserving, and the energy density and flux is derived. The general dispersion
relation is then derived, and we show that kinetic Alfv\'en waves exhibit an
instability for a low temperature and high density plasma. We discuss the
implication of our results.Comment: 6 pages, 1 figur
Plasma waves driven by gravitational waves in an expanding universe
In a Friedmann-Robertson-Walker (FRW) cosmological model with zero spatial
curvature, we consider the interaction of the gravitational waves with the
plasma in the presence of a weak magnetic field. Using the relativistic
hydromagnetic equations it is verified that large amplitude magnetosonic waves
are excited, assuming that both, the gravitational field and the weak magnetic
field do not break the homogeneity and isotropy of the considered FRW
spacetime.Comment: 14 page
Photon frequency conversion induced by gravitational radiation
We consider propagation of gravitational radiation in a magnetized
multicomponent plasma. It is shown that large density perturbations can be
generated, even for small deviations from flat space, provided the cyclotron
frequency is much larger than the plasma frequency. Furthermore, the induced
density gradients can generate frequency conversion of electromagnetic
radiation, which may give rise to indirect observational effect of the
gravitational waves.Comment: 13 pages, 1 figure, uses revtex, Accepted for publication in Phys.
Rev. D, Revised, appendix adde
Spin and magnetization effects in plasmas
We give a short review of a number of different models for treating
magnetization effects in plasmas. In particular, the transition between kinetic
models and fluid models is discussed. We also give examples of applications of
such theories. Some future aspects are discussed.Comment: 18 pages, 1 figure. To appear in Plasma Physics and Controlled
Fusion, Special Issue for the 37th ICPP, Santiago, Chil
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