摘要:

This is a summary of the topics covered on the single particle nonlinear dynamics of particle accelerators. In particular, discussions of calculation tools for analysis of beams in accelerators, current status of understanding the dynamics aperture, and the problem of ripple, effects have been given. ©1997 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.52955

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

This paper summarizes the main discussions of the Working Group on the Production and Dynamics of High Brightness Beams. The following topics are covered in this paper: proposed new electron sources and needed research on existing sources, discussions on issues relating to the description of phase space on non-thermalized electron beam distributions and the theoretical modeling on non-thermalized electron beam distributions, and the present status of the theoretical modeling of beam transport in bends. ©1997 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.52956

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The electric fields associated with density perturbations in a plasma can reach amplitudes much larger than obtained in conventional structures. These fields can be used to generate, accelerate and focus charged particle beams. Of primary importance are the parameters of the particle beams exiting the plasma: energy, current, emittance and duration. The topics that were discussed include plasma lenses, electron beam driven wakefield, self-modulated laser wakefield and crossed-beam wakefield. Some of these schemes have already been proven experimentally and will be the subject of second generation experiments. Some others only seen on paper and in simulations should be tested in the near future. ©1997 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.52932

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

This working group was charged with reviewing the general area of plasma phenomena in beams. The group reviewed our present understanding and discussed critical issues for a wide variety of topics, including longitudinal and transverse wakefield instabilities in high intensity rings, numerical computation of wakes at short scale length, ion instabilities, wakefields and emittance growth from coherent synchrotron radiation, the nature of self-amplified spontaneous emission (SASE), soliton theory and its role in beam physics, the control of transverse instabilities by feedback or by temporal variation of ring parameters, and the use of plasma concepts in beam dynamics, particularly applications of beam echo measurements. ©1997 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.52957

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

A few basic mechanisms underlying in the single-particle dynamics are reviewed with very simple examples. The subjects areresonance overlap,modulational diffusion, andArnold diffusion. Although these have been established by a number of people in these decades, and explained a lot of phenomena of single-particle motion, there still remain huge unsolved problems in this field. ©1997 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.52938

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The advent of laser driven RF Photoinjectors has raised the interest in the beam dynamics associated with intense, quasi-laminar, space charge dominated electron beams: the relevant phenomena observed in such a new regime of beam physics are presented and discussed in this paper. Most of the emphasis is focused on the analysis of the so called emittance correction technique, which is applied in the operation of RF guns in order to enhance the performances of these devices in terms of the attainable beam brightness, i.e., minimizing the beam emittance. A fully analytical description of this process is presented, based on an envelope equation treatment which leads to the concept ofinvariant envelope. The implications of such a concept are discussed and specific examples are given to compare the analytical predictions to the results of numerical simulations. ©1997 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.52944

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Rapid experimental progress on plasma-based acceleration has opened a new area of research for beam dynamicists. Important beam dynamics issues are characterizing beam loading limits, preserving emittance and minimizing energy spread. Basic models for these are introduced, and advanced topics for future work are identified. ©1997 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.52945

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

A broad spectrum of nonlinear collective effects have been identified and analyzed in the field of plasma physics which have direct analogs in high energy beams, though the spatial and time scales for these phenomena in beams differ markedly from those in typical laboratory plasmas. These effects range from the weakly nonlinear wave-wave scattering to those involving a stronger nonlinearity such as nonlinear Landau damping. The importance of studying these phenomena lies in the fact that such processes are likely involved in the saturation of instabilities and the consequent emittance growth. We report on observations of such phenomena in our hadron beams that bear a close resemblance to the classical nonlinear coherent phenomena in plasma physics and discuss implications for understanding and diagnosing nonlinear effects in beams. ©1997 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.52958

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Several methods have been developed recently to measure the frequencies of a time series to much higher precision than ordinary FFT. The decomposition of tracking or experimental data into a Fourier transform can therefore also be done with largely enhanced precision. On the one hand this allows to free these data from complicated phase space distortions. On the other hand, these high precision spectrum lines can be interpreted as being the result of the excitation of certain resonances. In this report we study how this information can be used to tackle resonances. It has to be stressed that this techniques requires no knowledge concerning the simulation model or the accelerator being studied. The only input needed is a series of tracking data or, in the case of the experiment, a set of turn-by-turn data after kicking the beam. ©1997 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.52946

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We investigate the statistical properties of symplectic maps with noise, describing a FODO cell with a sextupole and current ripples or misalignments in the magnets. Up to some distance from the dynamic aperture, the normal form associated to the map allows to compute analytically the diffusion coefficient due to a stochastic perturbation. The action diffusion is examined and very good agreement between the solutions of the Fokker-Planck (F.P.) equation and the simulations is obtained, for the He´non and SPS maps with a white noise. The corrections appearing for a correlated noise are discussed. ©1997 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.52926

出版商:AIP    

年代:1997

数据来源: AIP