High-frequency asymptotic behavior of radiation spectra of moving charges in classical electrodynamics

1986 ◽  
Vol 149 (8) ◽  
pp. 709 ◽  
Author(s):  
I.I. Abbasov ◽  
Boris M. Bolotovskii ◽  
Valerii A. Davydov
Keyword(s):  
Asymptotic Behavior ◽  
High Frequency ◽  
Classical Electrodynamics ◽  
Radiation Spectra

scholarly journals Limit Theory for High Frequency Sampled MCARMA Models

2014 ◽  
Vol 46 (3) ◽  
pp. 846-877 ◽  
Author(s):  
Vicky Fasen
Keyword(s):  
Asymptotic Behavior ◽  
High Frequency ◽  
Lévy Process ◽  
Asymptotic Properties ◽  
Domain Of Attraction ◽  
Levy Process ◽  
Sample Variance ◽  
Limit Theory ◽  
Second Moments ◽  
Time Grid

We consider a multivariate continuous-time ARMA (MCARMA) process sampled at a high-frequency time grid {hn, 2hn,…, nhn}, where hn ↓ 0 and nhn → ∞ as n → ∞, or at a constant time grid where hn = h. For this model, we present the asymptotic behavior of the properly normalized partial sum to a multivariate stable or a multivariate normal random vector depending on the domain of attraction of the driving Lévy process. Furthermore, we derive the asymptotic behavior of the sample variance. In the case of finite second moments of the driving Lévy process the sample variance is a consistent estimator. Moreover, we embed the MCARMA process in a cointegrated model. For this model, we propose a parameter estimator and derive its asymptotic behavior. The results are given for more general processes than MCARMA processes and contain some asymptotic properties of stochastic integrals.

High Frequency Vibrations in a Stiff Problem

1997 ◽  
Vol 07 (02) ◽  
pp. 291-311 ◽  
Author(s):  
Miguel Lobo ◽  
Eugenia Pérez
Keyword(s):  
Asymptotic Behavior ◽  
Spectral Problem ◽  
Continuous Spectrum ◽  
High Frequency ◽  
The Other ◽  
Stiff Problem ◽  
Eigenvalues And Eigenfunctions ◽  
High Frequencies ◽  
Stiffness Constant ◽  
High Frequency Vibrations

The stiff problem here considered models the vibrations of a body consisting of two materials, one of them very stiff with respect to the other. We study the asymptotic behavior of the eigenvalues and eigenfunctions of the corresponding spectral problem, when the stiffness constant of only one of the materials tends to 0. We show that the associated operator has a discrete spectrum "converging", in a certain sense, towards a continuous spectrum in [0,∞) corresponding to an operator. We also provide information on the structure of the eigenfunctions associated with the high frequencies.

A Novel Strategy for the Identification of Radiation Force Models

2014 ◽  
Author(s):  
Roman M. Janssen ◽  
Henk Jansen ◽  
Jan-Willem van Wingerden
Keyword(s):  
Asymptotic Behavior ◽  
Frequency Domain ◽  
High Frequency ◽  
State Of The Art ◽  
Radiation Force ◽  
The State ◽  
Test Cases ◽  
Subspace Identification ◽  
Domain Identification

A novel frequency domain identification (FDI) strategy for the identification of radiation force models from frequency domain hydrodynamic data is proposed. First, a subspace identification method is augmented with a convex constraint that guarantees a stable solution. Then, in a second convex optimization problem, constraints on low- and high frequency asymptotic behavior and passivity are enforced. This novel method, constrained frequency domain subspace identification (CFDSI), is validated by comparing both SISO and MIMO CFDSI results with the state-of-the-art FDI toolbox, which is part of the Marine Systems Simulator MATLAB toolbox. In two test cases, it is shown that the novel algorithm can successfully identify a model with either a SISO or MIMO structure, where stability, passivity and the desired low- and high-frequency asymptotic behavior are guaranteed. For the two test cases presented, the quality of the CFDSI models matches the quality of the state-of-the-art FDI models.

A Comparison of the Roughness Regimes in Hydrodynamic Lubrication

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
John Fabricius ◽  
Afonso Tsandzana ◽  
Francesc Perez-Rafols ◽  
Peter Wall
Keyword(s):  
Asymptotic Behavior ◽  
Stokes Flow ◽  
High Frequency ◽  
Reynolds Equation ◽  
Pressure Field ◽  
Hydrodynamic Lubrication ◽  
Narrow Gap ◽  
Surface Textures ◽  
Lubrication Regimes ◽  
Generalized Reynolds Equation

This work relates to previous studies concerning the asymptotic behavior of Stokes flow in a narrow gap between two surfaces in relative motion. It is assumed that one of the surfaces is rough, with small roughness wavelength μ, so that the film thickness h becomes rapidly oscillating. Depending on the limit of the ratio h/μ, denoted as λ, three different lubrication regimes exist: Reynolds roughness (λ = 0), Stokes roughness (0 < λ < ∞), and high-frequency roughness (λ = ∞). In each regime, the pressure field is governed by a generalized Reynolds equation, whose coefficients (so-called flow factors) depend on λ. To investigate the accuracy and applicability of the limit regimes, we compute the Stokes flow factors for various roughness patterns by varying the parameter λ. The results show that there are realistic surface textures for which the Reynolds roughness is not accurate and the Stokes roughness must be used instead.

The Crab nebula energy origin and its high frequency radiation spectra

2016 ◽  
Vol 82 (3) ◽  
Author(s):  
George Z. Machabeli ◽  
A. Rogava ◽  
N. Chkheidze ◽  
Z. Osmanov ◽  
D. Shapakidze
Keyword(s):  
Energy Transfer ◽  
Theoretical Model ◽  
Emission Spectrum ◽  
High Frequency ◽  
Crab Nebula ◽  
Synchrotron Emission ◽  
Physical Processes ◽  
Radiation Spectra ◽  
The Crab Nebula ◽  
Frequency Radiation

In the present work there is presented a model describing transfer of the Crab pulsar’s spin-down energy into the powerful synchrotron emission of the nebula. The process of the energy transfer consists of several consecutive stages. The physical processes underlying the theoretical model provide us with the synchrotron emission spectrum, which fits well with the observed one.

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