Interaction of gravitational waves with strongly magnetized plasmas (original) (raw)
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Gravitational waves in magnetized relativistic plasmas
Physical Review D, 2004
We study the propagation of gravitational waves (g w) in a uniformly magnetized plasma at arbitrary angles to the magnetic field. No a priori assumptions are made about the temperature, and we consider both a plasma at rest and a plasma flowing out at ultra-relativistic velocities. In the 3+1 orthonormal tetrad description, we find th at all three fundamental low-frequency plasma wave modes are excited by the g w. Alfven waves are excited by a x polarized g w , whereas the slow and fast magneto-acoustic modes couple to the + polarization. The slow mode, however, doesn't interact coherently with the g w. The most relevant wave mode is the fast magneto-acoustic mode which in a strongly magnetized plasma has a vanishingly small phase lag with respect to the g w allowing for coherent interaction over large length scales. W hen the background magnetic field is almost, but not entirely, parallel to the GW's direction of propagation even the Alfven waves grow to first order in the GW amplitude. Finally, we calculate the growth of the magneto-acoustic waves and the damping of the GW.
Propagation of gravitational waves in a magnetized plasma
Physical Review D, 1983
The propagation of gravitational waves parallel and perpendicular to a magnetic field in a collisionless plasma is considered. In the parallel case weak cyclotron damping of the gravitational waves exists, while in the perpendicular case there is coupling between gravitational and electromagnetic waves due to the generation of currents by the gravitational wave.
Resonant interaction between gravitational waves, electromagnetic waves, and plasma flows
Physical Review D, 2003
In magnetized plasmas gravitational and electromagnetic waves may interact coherently and exchange energy between themselves and with plasma flows. We derive the wave interaction equations for these processes in the case of waves propagating perpendicular or parallel to the plasma background magnetic field. In the latter case, the electromagnetic waves are taken to be circularly polarized waves of arbitrary amplitude. We allow for a background drift flow of the plasma components which increases the number of possible evolution scenarios. The interaction equations are solved analytically and the characteristic time scales for conversion between gravitational and electromagnetic waves are found. In particular, it is shown that in the presence of a drift flow there are explosive instabilities resulting in the generation of gravitational and electromagnetic waves. Conversely, we show that energetic waves can interact to accelerate particles and thereby produce a drift flow. The relevance of these results for astrophysical and cosmological plasmas is discussed.
Fast magnetosonic waves driven by gravitational waves
Astronomy and Astrophysics, 2001
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 generalrelativistic 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.
Indirect visibility of gravitational waves in magnetohydrodynamic plasmas
Arxiv preprint gr-qc/0503074, 2005
We propose a mechanism to make gravitational waves (GWs) visible in the electromagnetic domain. Gravitational waves that propagate through a strongly magnetized plasma interact with the plasma through its anisotropic stress-energy tensor and excite magnetohydrodynamic (MHD) wave modes. In catastrophic events such as the merger of a double neutron star binary, a large fraction of the total binding energy of the system is released in the form of GWs observable by LIGO, and the amount of energy transferred to the MHD waves is substantial. These modes, however, are excited at the same frequency as the GW and are not directly observable. In this paper we investigate radiation processes that operate in the presence of the gravitationally excited MHD waves and radiate in the radio regime accessible to LOFAR. We present order of magnitude estimates for the spectral flux of a merger detectable by a LOFAR.
Gravitational and magnetosonic waves in gamma-ray bursts
Astronomy & Astrophysics, 2003
One of the possible sources of gamma-ray bursts (s) are merging, compact neutronstar binaries. More than 90% of the binding energy of such a binary is released in the form of gravitational waves (s) in the last few seconds of the spiral-in phase before the formation of a black hole. In this article we investigate whether a fraction of this energy is transferred to magnetohydrodynamic waves in the magnetized plasma wind around the binary. Using the 3 + 1 orthonormal tedrad formalism, we study the propagation of a monochromatic, plane fronted, linearly polarized perpendicular to the ambient magnetic field in an ultra-relativistic wind, first in the comoving and then in the observer frame. A closed set of general relativistic magnetohydrodynamic () equations is derived in the form of conservation laws for electric charge, matter energy, momentum and magnetic energy densities. We linearize the equations under the action of a monochromatic , which acts as a driver and find that fast magneto-acoustic waves grow, with amplitudes proportional to the amplitude and frequency and the strength of the background magnetic field.
Nonlinear gravitational wave interactions with plasmas
Physical Review D, 2000
We consider the interactions of a strong gravitational wave with electromagnetic fields using the 1ϩ3 orthonormal tetrad formalism. A general system of equations is derived, describing the influence of a plane fronted parallel (pp) gravitational wave on a cold relativistic multicomponent plasma. We focus our attention on phenomena that are induced by terms that are higher order in the gravitational wave amplitude. In particular, it is shown that parametric excitations of plasma oscillations take place, due to higher order gravitational nonlinearities. The implications of the results are discussed.
Astronomy 2, 105–127, 2023
The general-relativistic (GR) magnetohydrodynamic (MHD) equations for a conductive plasma fluid are derived and discussed in the curved spacetime described by Thorne’s metric tensor, i.e., a family of cosmological models with inherent anisotropy due to the existence of an ambient magnetic field. In this framework, it is examined whether the magnetized plasma fluid that drives the evolution of such a model can be subsequently excited by a transient, plane-polarized gravitational wave (GW) or not. To do so, we consider the associated set of the perturbed equations of motion and integrate them numerically in order to study the evolution of instabilities triggered by the GW propagation. In particular, we examine to what extend perturbations of the electric and/or the magnetic field can be amplified due to a potential energy transfer from the GW to the electromagnetic (EM) degrees of freedom. The evolution of the perturbed quantities depends on four free parameters, namely, the conductivity of the fluid, σ; the speed of sound square, 1/3 < (Cs/c)^2 ≡ γ < 1, which in this model may serve also as a measure of the inherent anisotropy; the GW frequency, ωg; and the associated angle of propagation with respect to the direction of the magnetic field, θ. We find that GW propagation in the anisotropic magnetized medium under consideration does excite several MHD modes; in other words, there is energy transfer from the gravitational to the EM degrees of freedom that can result in the acceleration of charged particles at the spot and in the subsequent damping of the GW.
Nonlinear gravitational waves in plasma
Russ Phys J, 1981
An exact solution is obtained for relativistic collisionless kinetic equations describing a test plasma in the field of a strong plane gravitational wave. It is found that longitudinal electric current is induced in the plasma by the gravitational wave; the current amplitude reaches the maximum at electron temperatures approximately equal to the electron mass times the squared speed of light. The interaction between gravitational waves and a system consisting of Boltzmann ions and degenerated electrons is also discussed.