364 research outputs found
Dispersion Properties, Nonlinear Waves and Birefringence in Classical Nonlinear Electrodynamics
Using the very basic physics principles, we have studied the implications of
quantum corrections to classical electrodynamics and the propagation of
electromagnetic waves and pulses.
The initial nonlinear wave equation for the electromagnetic vector potential
is solved perturbatively about the known exact plane wave solution in both the
free vacuum case, as well as when a constant magnetic field is applied. A
nonlinear wave equation with nonzero convective part for the (relatively)
slowly varying amplitude of the first-order perturbation has been derived. This
equation governs the propagation of electromagnetic waves with a reduced speed
of light, where the reduction is roughly proportional to the intensity of the
initial pumping plane wave. A system of coupled nonlinear wave equations for
the two slowly varying amplitudes of the first-order perturbation, which
describe the two polarization states, has been obtained for the case of
constant magnetic field background.
Further, the slowly varying wave amplitude behavior is shown to be similar to
that of a cnoidal wave, known to describe surface gravity waves in shallow
water. It has been demonstrated that the two wave modes describing the two
polarization states are independent, and they propagate at different wave
frequencies. This effect is usually called nonlinear birefringence.Comment: 11 pages, 3 figure
Use of imaging plates at near saturation for high energy density particles
Copyright 2008 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Review of Scientific Instruments, 79(10), 10E910, 2008 and may be found at http://dx.doi.org/10.1063/1.298767
Effect of Cu impurities on wet etching of Si(110): formation of trapezoidal hillocks
We simulate the formation of experimentally observed trapezoidal hillocks on etched Si(110) surfaces, describing their generic geometrical shape and analyzing the relative stability and/or reactivity of the key surface sites. In our model, the hillocks are stabilized by Cu impurities in the etchant adsorbing on the surface and acting as pinning agents. A model of random adsorptions will not result in hillock formation since a single impurity is easily removed from the surface. Instead a whole cluster of Cu atoms is needed as a mask to stabilize a hillock. Therefore we propose and analyze mechanisms that drive correlated adsorptions and lead to stable Cu clusters.Peer reviewe
Split-aperture laser pulse compressor design tolerant to alignment and line-density differences
This paper was published in Optics Letters and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OL.33.001902 Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law
Side-on measurement of hydrodynamics of laser-driven plasmas with high space- and time-resolution x-ray imaging technique
Copyright 2003 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Review of Scientific Instruments, 74(3), 2198-2201, 2003 and may be found at http://dx.doi.org/10.1063/1.153785
Calibration of imaging plate for high energy electron spectrometer
Copyright 2005 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Review of Scientific Instruments, 76(1), 013507_1-013507_5, 2005 and may be found at http://dx.doi.org/10.1063/1.182437
Discovery of the Central Excess Brightness in Hard X-rays in the Cluster of Galaxies Abell 1795
Using the X-ray data from \ASCA, spectral and spatial properties of the
intra-cluster medium (ICM) of the cD cluster Abell 1795 are studied, up to a
radial distance of ( kpc). The ICM
temperature and abundance are spatially rather constant, although the cool
emission component is reconfirmed in the central region. The azimuthally-
averaged radial X-ray surface brightness profiles are very similar between soft
(0.7--3 keV) and hard (3--10 keV) energy bands, and neither can be fitted with
a single- model due to a strong data excess within of the
cluster center. In contrast, double- models can successfully reproduce
the overall brightness profiles both in the soft and hard energy bands, as well
as that derived with the \ROSAT PSPC. Properties of the central excess
brightness are very similar over the 0.2--10 keV energy range spanned by \ROSAT
and \ASCA. Thus, the excess X-ray emission from the core region of this cluster
is confirmed for the first time in hard X-rays above 3 keV. This indicates that
the shape of the gravitational potential becomes deeper than the King-type one
towards the cluster center. Radial profiles of the total gravitating matter,
calculated using the double- model, reveal an excess mass of within kpc of the cluster
center. This suggests a hierarchy in the gravitational potential corresponding
to the cD galaxy and the entire cluster.Comment: 27 pages, 8 figures; to appear ApJ 500 (June 20, 1998
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