1,721,033 research outputs found
Operational methods for integro-differential equations and applications to problems in particle accelerator physics
No full textEvolution operators and Euler angles
No full textThe Euler rotation matrix and angles are derived within a context exploiting evolution operators for vector differential equations
Motion of bodies in apparent force fields and evolution operator methods
No full textWe show, that methods currently exploited in quantum mechanics, like the evolution operator technique, can be employed to deal with the motion of bodies subject to apparent forces. The method we propose allows the inclusion of velocity-dependent forces of friction type and offers the possibility of developing fast and reliable algorithms for numerical computations
An operational solution for the motion equation of bodies in non-inertial frames
No full textWe show that the recently developed techniques, involving the evolution operator method, can be extended to second-order vector differential equations and exact solutions. We apply this method to the solution of the problem of motion for bodies moving in non-inertial frames. We obtain exact solutions for equations of motion including both Coriolis and centrifugal terms. © Società Italiana di Fisica
Saw-tooth instability in storage rings: simulations and dynamical model
No full textThe saw-tooth instability in storage rings is studied by means of a time-domain simulation code which takes into account the self-induced wake fields. The results are compared with those from a dynamical heuristic model exploiting two coupled non-linear differential equations, accounting for the time behavior of the instability growth rate and for the anomalous growth of the energy spread. This model is shown to reproduce the characteristic features of the instability in a fairly satisfactory way. (C) 1999 Elsevier Science B.V. All rights reserved
Storage ring free electron lasers and saw-tooth instability
No full textWe show that Free Electron Lasers (FEL) operating with storage rings may counteract beam instabilities of the Saw Tooth (STI) type. We use a model based on a set of equations that couple those describing the FEL evolution to those accounting for the STI dynamics. The analysis provides a clear picture of the FEL-STI mutual feedback and clarifies the mechanisms of the instability inhibition. The reliability of the results is supported by a comparison with fully numerical codes. (C) 1999 Elsevier Science B.V. All rights reserved
Storage ring free electron laser dynamics, with the inclusion of bunch lengthening and energy spread increasing effects
No full textWe develop a rate equation model of the Storage Ring kee Electron Laser dynamics, which includes bunch lengthening and energy spread increasing effects, due to the combined mechanism of potential well distortion and collective random excitations. The model is based On the ordinary storage ring Free Electron Laser equations, coupled to Haissinski-type equations, accounting for the previously quoted effects. The obtained results are shown to provide a reliable tool, yielding a transparent understanding of the interplay between Free Electron Laser and e-beam induced effects
Storage ring free-electron laser and microwave-type instabilities
No full textWe present general considerations on the interplay between free-electron laser dynamics and storage ring instabilities of microwave type. We develop a dynamical model capable of including the laser and the instability dynamics. We analyze the conditions ensuring the switch off of the instability and the successful operation of the laser
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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