The Experts below are selected from a list of 124236 Experts worldwide ranked by ideXlab platform
Danny Summers - One of the best experts on this subject based on the ideXlab platform.
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relativistic electron precipitation induced by emic triggered emissions in a dipole magnetosphere
Journal of Geophysical Research, 2015Co-Authors: Yuko Kubota, Danny Summers, Yoshiharu OmuraAbstract:We perform test particle simulations of relativistic electrons interacting with electromagnetic ion cyclotron (EMIC)-triggered emissions in the plasmasphere. EMIC-triggered emissions are generated by energetic protons injected into the inner magnetosphere. EMIC-triggered emissions are characterized by large wave amplitudes, rising-tone frequencies, and coherent left-hand circularly polarized waves. We study trajectories of relativistic radiation belt electrons drifting eastward interacting with longitudinally distributed EMIC-triggered emissions. Some electrons are trapped by wave potentials and efficiently guided down to lower pitch angles. Repeated interactions occur due to the mirror motion and result in the Scattering of Particles into the loss cone. We use two EMIC wave models for the test particle simulations. One assumes that the wave amplitude is constant, and the other assumes a time-dependent wave amplitude that characterizes subpackets. Both model waves are resonant with 0.5–6.0 MeV electrons and precipitate them. Electrons in the energy range 1.1–3.0 MeV are precipitated most efficiently. Approximately 50% of the total injected number of 1.1–3.0 MeV electrons are precipitated in a timescale of 2 min. We obtain the relativistic electron distribution in equatorial pitch angle and in pitch angle at the atmosphere. Further, we determine the timing and longitudinal location of the relativistic electron precipitation with respect to different particle energies.
Yu V Pavlov - One of the best experts on this subject based on the ideXlab platform.
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on particle collisions near rotating black holes
Gravitation & Cosmology, 2011Co-Authors: A A Grib, Yu V PavlovAbstract:Scattering of Particles with different masses and energy in the gravitational field of rotating black holes is considered both outside and inside the black hole. Expressions for Scattering energy of Particles in the center-of-mass reference frame are obtained. It is shown that the Scattering energy of Particles in this frame can acquire very large values not only for extremal black holes but also for nonextremal ones if one takes into account multiple Scattering. Numerical estimates for the time needed for a particle to get ultrarelativistic energy are given.
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on particle collisions in the gravitational field of the kerr black hole
Astroparticle Physics, 2011Co-Authors: A A Grib, Yu V PavlovAbstract:Abstract Scattering of Particles in the gravitational field of Kerr black holes is considered. It is shown that Scattering energy of Particles in the centre of mass system can obtain very large values not only for extremal black holes but also for nonextremal ones existing in Nature. This can be used for explanation of still unresolved problem of the origin of ultrahigh energy cosmic rays observed in Auger experiment. Extraction of energy after the collision is investigated. It is shown that due to the Penrose process the energy of the particle escaping the hole at infinity can be large. Contradictions in the problem of getting high energetic Particles escaping the black hole are resolved.
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on particle collisions near kerr s black holes
arXiv: General Relativity and Quantum Cosmology, 2010Co-Authors: A A Grib, Yu V PavlovAbstract:Scattering of Particles in the gravitational field of rotating black holes is considered. Expressions for Scattering energy of Particles in the centre of mass system are obtained. It is shown that Scattering energy of Particles in the centre of mass system can obtain very large values not only for extremal black holes but also for nonextremal ones. It is shown that for realizing of the collisions with infinite energy one needs the infinite interval not only of the coordinate time but also the infinite interval of the proper time of the free falling particle.
Loyal Durand - One of the best experts on this subject based on the ideXlab platform.
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asymptotic bessel function expansions for legendre and jacobi functions
Journal of Mathematical Physics, 2019Co-Authors: Loyal DurandAbstract:We present new asymptotic series for the Legendre and Jacobi functions of the first and second kinds in terms of Bessel functions with appropriate arguments. The results are useful in the context of Scattering problems, improve on known limiting results, and allow the calculation of corrections to the leading Bessel-function approximations for these functions. Our derivations of these series are based on Barnes-type representations of the Legendre, Jacobi, and Bessel functions; our method appears to be new. We use the results, finally, to obtain asymptotic Bessel function expansions for the rotation functions needed to describe the Scattering of Particles with spin.We present new asymptotic series for the Legendre and Jacobi functions of the first and second kinds in terms of Bessel functions with appropriate arguments. The results are useful in the context of Scattering problems, improve on known limiting results, and allow the calculation of corrections to the leading Bessel-function approximations for these functions. Our derivations of these series are based on Barnes-type representations of the Legendre, Jacobi, and Bessel functions; our method appears to be new. We use the results, finally, to obtain asymptotic Bessel function expansions for the rotation functions needed to describe the Scattering of Particles with spin.
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asymptotic bessel function expansions for legendre and jacobi functions
arXiv: Mathematical Physics, 2018Co-Authors: Loyal DurandAbstract:We present new asymptotic series for the Legendre and Jacobi functions of the first and second kinds in terms of Bessel functions with appropriate arguments. The results are useful in the context of Scattering problems, improve on known limiting results, and allow the calculation of corrections to the leading Bessel-function approximations for these functions. Our derivations of these series are based on Barnes-type representations of the Legendre, Jacobi, and Bessel functions; our method appears to be new. We use the results, finally, to obtain asymptotic Bessel function expansions for the rotation functions needed to describe the Scattering of Particles with spin.
A A Grib - One of the best experts on this subject based on the ideXlab platform.
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on particle collisions near rotating black holes
Gravitation & Cosmology, 2011Co-Authors: A A Grib, Yu V PavlovAbstract:Scattering of Particles with different masses and energy in the gravitational field of rotating black holes is considered both outside and inside the black hole. Expressions for Scattering energy of Particles in the center-of-mass reference frame are obtained. It is shown that the Scattering energy of Particles in this frame can acquire very large values not only for extremal black holes but also for nonextremal ones if one takes into account multiple Scattering. Numerical estimates for the time needed for a particle to get ultrarelativistic energy are given.
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on particle collisions in the gravitational field of the kerr black hole
Astroparticle Physics, 2011Co-Authors: A A Grib, Yu V PavlovAbstract:Abstract Scattering of Particles in the gravitational field of Kerr black holes is considered. It is shown that Scattering energy of Particles in the centre of mass system can obtain very large values not only for extremal black holes but also for nonextremal ones existing in Nature. This can be used for explanation of still unresolved problem of the origin of ultrahigh energy cosmic rays observed in Auger experiment. Extraction of energy after the collision is investigated. It is shown that due to the Penrose process the energy of the particle escaping the hole at infinity can be large. Contradictions in the problem of getting high energetic Particles escaping the black hole are resolved.
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on particle collisions near kerr s black holes
arXiv: General Relativity and Quantum Cosmology, 2010Co-Authors: A A Grib, Yu V PavlovAbstract:Scattering of Particles in the gravitational field of rotating black holes is considered. Expressions for Scattering energy of Particles in the centre of mass system are obtained. It is shown that Scattering energy of Particles in the centre of mass system can obtain very large values not only for extremal black holes but also for nonextremal ones. It is shown that for realizing of the collisions with infinite energy one needs the infinite interval not only of the coordinate time but also the infinite interval of the proper time of the free falling particle.
Roberta Lazzari - One of the best experts on this subject based on the ideXlab platform.
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IsGISAXS: A program for grazing-incidence small-angle X-ray Scattering analysis of supported islands
Journal of Applied Crystallography, 2002Co-Authors: Roberta LazzariAbstract:This paper describes a Fortran program, IsGISAXS, for the simulation and analysis of grazing-incidence small-angle X-ray Scattering (GISAXS) of islands supported on a substrate. As is usual in small-angle Scattering of Particles, the Scattering cross section is expressed in terms of an island form factor and interference function. However, the emphasis is placed on the specificity of the grazing-incidence geometry, in particular in the evaluation of the island form factor in the distorted-wave Born approximation. A library of simple geometrical shapes is available. A full account of size and possible shape distributions is given in the decoupling approximation, where sizes and positions are not correlated, and in the local monodisperse approximation. Two types of island repartitions on the substrate are considered: disordered systems characterized by their particle-particle pair correlation functions, and bidimensional crystalline or paracrystalline systems of Particles.
