Topic
Free electron model
About: Free electron model is a research topic. Over the lifetime, 4678 publications have been published within this topic receiving 103535 citations.
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TL;DR: In this paper, the problem of oscillator evolution and mode competition in free electron lasers is studied, where Relativistic quantum field theory is used to calculate electron wave functions, the angular distribution of spontaneous emission and the transition rates for stimulated emission and absorption in each mode.
Abstract: The problem of oscillator evolution and mode competition in free electron lasers is studied. Relativistic quantum field theory is used to calculate electron wave functions, the angular distribution of spontaneous emission, and the transition rates for stimulated emission and absorption in each mode. The photon rate equation for the weak-field regime is presented. This rate equation is applied to oscillator evolution with a conventional undulator, a two-stage optical klystron, and a tapered undulator. The effects of noise are briefly discussed.
29 citations
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TL;DR: In this paper, a set of numerical solvers for the linear dispersion relations of the gyrokinetic (GK), the hybrid-kinetic, and the fully kinetic (FK) model is employed to study the physics of the KAW and the fast magnetosonic mode in these models.
Abstract: A set of numerical solvers for the linear dispersion relations of the gyrokinetic (GK), the hybrid-kinetic (HK), and the fully kinetic (FK) model is employed to study the physics of the KAW and the fast magnetosonic mode in these models In particular, we focus on parameters that are relevant for solar wind oriented applications (using a homogeneous, isotropic background), which are characterized by wave propagation angles averaging close to 90° It is found that the GK model, while lacking high-frequency solutions and cyclotron effects, faithfully reproduces the FK wave physics close to, and sometimes significantly beyond, the boundaries of its range of validity The HK model, on the other hand, is much more complete in terms of high-frequency waves, but owing to its simple electron model it is found to severely underpredict wave damping rates even on ion spatial scales across a large range of parameters, despite containing full kinetic ion physics
29 citations
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TL;DR: In this article, a fluid-kinetic hybrid electron model was developed for toroidal geometry simulations and the wave propagation in a fully global gyrokinetic particle simulation was investigated in the long-wavelength magnetohydrodynamic limit.
Abstract: Electromagnetic gyrokinetic simulation in toroidal geometry is developed based on a fluid-kinetic hybrid electron model. The Alfven wave propagation in a fully global gyrokinetic particle simulation is investigated. In the long-wavelength magnetohydrodynamic limit, shear Alfven wave oscillations, continuum damping, and the appearance of the frequency gap in toroidal geometries are demonstrated. Wave propagation across the magnetic field (kinetic Alfven wave) is examined by comparing the simulation results with the theoretical dispersion relation. Furthermore, finite-beta stabilization of the ion temperature gradient mode and the onset of the kinetic ballooning mode are demonstrated.
29 citations
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TL;DR: In this article, the free electron laser on the basis of parametric (quasi-Cerenkov) instability is considered and threshold conditions for this process are obtained, and it is shown that rather rigid requirements for the particle beam are needed in the X-ray region.
Abstract: The free electron laser on the basis of parametric (quasi-Cerenkov) instability is considered. Threshold conditions for this process are obtained. It is shown that rather rigid requirements for the particle beam are needed in the X-ray region.
29 citations
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TL;DR: The angular correlation of the photons produced in electron-positron annihilation is a panticularly suitable method for studying the conduction electrons in liquid metals as mentioned in this paper, and it is a technique which can be applied to disordered systems, and the angular distribution of photons reflects directly the momentum distribution of the electrons.
29 citations