December 22nd, 2020

лошадь, диаграмма, Фейнман

Матриалы очередной ЦЕРНовской школы по ускорителям

На сей раз - численные методы (пост будет дополняться):

Numerical analysis techniques for non-linear dynamics: https://arxiv.org/abs/2012.10552
Yannis Papaphilippou
The content of this contribution is based on the course on numerical analysis techniques for non-linear dynamics. After introducing basic concepts as the visual analysis of trajectories in phase space and the importance of the nature of fixed points in their topology and dynamics, the motion close to a resonance is presented, with simple non-linear map examples. The onset of chaotic motion and the modern methods used for their detection are detailed with a focus on frequency map analysis and concrete examples for a variety of rings and non-linear effects.
Comments: 27 pages, 25 figures, Proceedings of the 2018 CERN--Accelerator--School course on Numerical Methods for Analysis, Design and Modelling of Particle Accelerators, Thessaloniki, Greece
лошадь, диаграмма, Фейнман

Источники гамма-излучения нового поколения

International Workshop on Next Generation Gamma-Ray Source: https://arxiv.org/abs/2012.10843

A workshop on The Next Generation Gamma-Ray Sources sponsored by the Office of Nuclear Physics at the Department of Energy, was held November 17--19, 2016 in Bethesda, Maryland. The goals of the workshop were to identify basic and applied research opportunities at the frontiers of nuclear physics that would be made possible by the beam capabilities of an advanced laser Compton beam facility. To anchor the scientific vision to realistically achievable beam specifications using proven technologies, the workshop brought together experts in the fields of electron accelerators, lasers, and optics to examine the technical options for achieving the beam specifications required by the most compelling parts of the proposed research programs. An international assembly of participants included current and prospective γ-ray beam users, accelerator and light-source physicists, and federal agency program managers. Sessions were organized to foster interactions between the beam users and facility developers, allowing for information sharing and mutual feedback between the two groups. The workshop findings and recommendations are summarized in this whitepaper.
лошадь, диаграмма, Фейнман

Как вытянуть всю электродинамику из закона Кулона

Direct derivation of Lienard Wiechert potentials, Maxwell's equations and Lorentz force from Coulomb's law: https://arxiv.org/abs/2012.11370
Hrvoje Dodig
In 19th century Maxwell derived Maxwell equations from the knowledge of three experimental physical laws: the Coulomb's law, the Ampere's force law and Faraday's law of induction. However, theoretical basis for Ampere's force law and Faraday's law remains unknown to this day. Furthermore, the Lorentz force is considered as experimental phenomena, the theoretical foundation of this force is still unknown.
To answer these fundamental theoretical questions, we derive Lienard Wiechert potentials, Maxwell's equations and Lorentz force from two simple postulates: (a) when all charges are at rest the Coulomb's force acts between the charges, and (b) that disturbances caused by charge in motion propagate away from the source with finite velocity. The special relativity was not used in our derivations nor the Lorentz transformation. In effect, it was shown all the electrodynamic laws, including the Lorentz force, can be derived from Coulomb's law and time retardation.
This was accomplished by analysis of hypothetical experiment where test charge is at rest and where previously moving source charge stops at some time in the past. Then the generalized Helmholtz decomposition theorem, also derived in this paper, was applied to reformulate Coulomb's force acting at present time as the function of positions of source charge at previous time when the source charge was moving. From this reformulation of Coulomb's law the Lienard Wiechert potentials and Maxwell's equations were derived.
In the second part of this paper, the energy conservation principle valid for moving charges is derived from the knowledge of electrostatic energy conservation principle valid for stationary charges. This again was accomplished by using generalized Helmholtz decomposition theorem. From this dynamic energy conservation principle the Lorentz force is derived.