Anisotropic enhanced backscattering induced by anisotropic diffusion

Bret, Boris P. J.; Lagendijk, Aart

doi:10.1103/physreve.70.036601

Cited by 21 publications

(32 citation statements)

References 31 publications

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“…We then presented a plausible alternative mechanism for extracting the kinetic energy of the ultra-relativistic pairs: plasma beam instabilities. Despite the extraordinarily dilute nature of this ultra-relativistic pair plasma, we found a variety of plasma instabilities which grow on timescales short in comparison to the inverse-Compton cooling time, the most important of which is the "oblique" instability (Bret et al 2004). Via this instability, these ultra-relativistic pairs lose their kinetic energy by depositing it as heat in the IGM.…”

Section: Introductionmentioning

confidence: 91%

THE COSMOLOGICAL IMPACT OF LUMINOUS TeV BLAZARS. II. REWRITING THE THERMAL HISTORY OF THE INTERGALACTIC MEDIUM

Chang

Broderick

Pfrommer

2012

ApJ

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The Universe is opaque to extragalactic very high-energy gamma rays (VHEGRs, E > 100 GeV) because they annihilate and pair produce on the extragalactic background light. The resulting ultra-relativistic pairs are commonly assumed to lose energy primarily through inverse Compton scattering of cosmic microwave background photons, reprocessing the original emission from TeV to GeV energies. In Broderick et al. (2012, Paper I of this three paper series), we argued that this is not the case; powerful plasma instabilities driven by the highly anisotropic nature of the ultra-relativistic pair distribution provide a plausible way to dissipate the kinetic energy of the TeV-generated pairs locally, heating the intergalactic medium (IGM). Here, we explore the effect of this heating upon the thermal history of the IGM. We collate the observed extragalactic VHEGR sources to determine a local VHEGR heating rate. Given the pointed nature of VHEGR observations, we estimate the correction for the various selection effects using Fermi observations of high and intermediate peaked BL Lacs. As the extragalactic component of the local VHEGR flux is dominated by TeV blazars, we then estimate the evolution of the TeV blazar luminosity density by tying it to the well-observed quasar luminosity density, and producing a VHEGR heating rate as a function of redshift. This heating is relatively homogeneous for z 4, but there is greater spatial variation at higher redshift (order unity at z ∼ 6) because of the reduced number of blazars that contribute to local heating. We show that this new heating process dominates photoheating in the low-redshift evolution of the IGM and calculate the effect of this heating in a one-zone model. As a consequence, the inclusion of TeV blazar heating qualitatively and quantitatively changes the structure and history of the IGM. Due to the homogeneous nature of the extragalactic background light, TeV blazars produce a uniform volumetric heating rate. This heating is sufficient to increase the temperature of the mean density IGM by nearly an order of magnitude, and at low densities by substantially more. It also naturally produces the inverted temperature-density relation inferred by recent observations of the high-redshift Lyα forest, a feature that is difficult to reconcile with standard reionization models. Finally, we close with a discussion on the possibility of detecting this hot low-density IGM suggested by our model either directly or indirectly via the local Lyα forest, the Comptonized cosmic microwave background, or free-free emission, but find that such measurements are currently not feasible.

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Section: Introductionmentioning

confidence: 91%

THE COSMOLOGICAL IMPACT OF LUMINOUS TeV BLAZARS. II. REWRITING THE THERMAL HISTORY OF THE INTERGALACTIC MEDIUM

Chang

Broderick

Pfrommer

2012

ApJ

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“…Figure 4 shows the angular distribu- Figure 4 is the horizontal cross section of the CBS image through the center of the CBS peak. Limited by the size of the CCD, the right tails are not recorded completely, but they can also be fitted well [12,28].…”

Section: Cbs Experimentsmentioning

confidence: 99%

“…Anisotropic propagation properties of light are studied mainly by transmission measurements [10,12], coherent backscattering (CBS) [11,12,18] and time-resolved techniques [810]. Recently, it has been demonstrated that the anisotropic propagation of light can be controlled by a polarized pump light in a water suspension of anisotropic congruent lithium niobate (CLN) microcrystal particles in the weak localization regime [18].…”

Section: Introductionmentioning

confidence: 99%

“…Anisotropic propagation of light in disordered materials, which is one of the most interesting phenomena in diffuse optical tomography, weak and strong (or Anderson) localization, is widely studied both in theories [17] and in experiments [818] through porous plastic fiber [16], various biological systems [1315] and essential optic materials (liquid crystal [8,9,11], macroporous semiconductor [10,12], and lithium niobate [18]). Anisotropic propagation properties of light are studied mainly by transmission measurements [10,12], coherent backscattering (CBS) [11,12,18] and time-resolved techniques [810].…”

Section: Introductionmentioning

confidence: 99%

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Wavelength dependence of light propagation in a water suspension of anisotropic scatterers

Shi

Zhang

et al. 2011

Sci. China Phys. Mech. Astron.

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We experimentally study the wavelength dependence of light propagation in a water suspension of lithium niobate microcrystalline particles. First, the ballistic transmission in the visible range of the suspension is measured. The nonlinear relationship is observed between the transport mean free path and the wavelength of the incident light. Secondly, we measure the coherent backscattering (CBS) of the sample at different wavelengths. The full width at half maximum of the CBS cone at 532 nm is about 1.24 times as large as that at 671 nm. The results indicate that the light with a long wavelength propagates further than the short wavelength light and the localization state of the short one is stronger. Finally, we investigate the light-controllable CBS experiments in the disordered materials of anisotropic scatterers, which show that the configuration of pump light with the longer wavelength and the probe light with the shorter wavelength performs better.wavelength dependence, light propagation in random media, anisotropic scatterers, light-control PACS: 42.25.Dd, 42.25.Fx, 42.25.Kb

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“…Beginning with ground breaking works [9][10][11], main effects were obtained in suspensions or homogeneous powders and ceramics [12]. At the same time-most applications, in particular, biomedical ones [13][14][15][16][17]-deal with optically anisotropic media with pronounced liquid crystal properties.…”

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confidence: 99%

Simulation of multiple light scattering in a bounded nematic

Kuzmin

2014

Opt. Spectrosc.

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The multiple scattering problem is formulated for a single constant model of a nematic liquid crystal with allowance for the dependence on the orienting external magnetic field. Based on the Bethe-Sal peter equation, an original Monte Carlo procedure in a birefringent medium is developed with allowance for the long range action of dielectric permittivity fluctuations and backward and forward scatterings are calcu lated. The dependence of multiple scattering in a nematic on the distance between the incident and scattered rays is quantitatively studied for the first time and a nonmonotonic dependence on the external magnetic field is discovered. We numerically have established that the light diffusion anisotropy noticeably weakens as com pared to the extinction length anisotropy; this is shown to be caused by the weak anisotropy of the transport length.

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Anisotropic enhanced backscattering induced by anisotropic diffusion

Cited by 21 publications

References 31 publications

THE COSMOLOGICAL IMPACT OF LUMINOUS TeV BLAZARS. II. REWRITING THE THERMAL HISTORY OF THE INTERGALACTIC MEDIUM

THE COSMOLOGICAL IMPACT OF LUMINOUS TeV BLAZARS. II. REWRITING THE THERMAL HISTORY OF THE INTERGALACTIC MEDIUM

Wavelength dependence of light propagation in a water suspension of anisotropic scatterers

Simulation of multiple light scattering in a bounded nematic

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