摘要:

In this lecture we will develop a concept of wakes and impedances for relativistic beams interacting with the surrounding environment. Among the numerous publications and reviews on this subject, we refer here to recent books [1–3], where the reader can find a more detailed treatment and further references. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1420417

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

After introducing the concepts of longitudinal wakefield and coupling impedance, we review the theory of longitudinal single-bunch collective effects in storage rings. From the Fokker-Planck equation we first derive the stationary solution describing the natural single-bunch regime, and then treat the problem of microwave instability, showing the different approaches used for estimating the threshold current. We end the lecture with the semi-empirical laws that allow us to obtain the single-bunch behavior above threshold, and with a description of the simulation codes that are now reliable tools for investigating all these effects. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1420418

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

Transverse mode coupling instabilities (TMCI) emerged between 1974 and 1980 as the main limitation of dense bunches in electron synchrotrons and storage rings. A two-particle model allows one to calculate the beam break-up (BBU) instability in linacs. Extending this to synchrotrons shows that the BBU instability is suppressed below a threshold intensity by synchrotron oscillations. The classical theory of head-tail modes, together with the general properties of coupling impedances, is used to show how single bunches become unstable when head-tail modes couple together: this is the TMCI threshold. Above threshold, observations in both proton and electron synchrotrons can be described by BBU theory. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1420419

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

A general approach to the analysis of spin motion in realistic accelerator fields is presented. A method of finding the “spin closed orbit” and spin tune in arbitrary field configurations is given. It is shown that spin-orbital resonances perturb the spin motion and can cause depolarization. Methods of safe resonance crossing for protons are presented, including schemes with a few Siberian snakes and spin rotators in the rings. The effects of radiation on the spin of electrons are considered and illustrated by experiences in electron storage rings in the energy range from 500 MeV to 60 GeV. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1420420

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

Among different approaches the Vlasov equations present the most comprehensive way to study the coherent oscillations of beams in cases, where coherent oscillations develop faster than the rates of beam relaxation due to stochastic processes. The differences in the frequencies of the beam particle motions result in decoherence of the beam and in Landau damping of coherent modes. This is a special damping mechanism which appears due to differences in the interactions of various beam particles with excited coherent oscillations. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1420421

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

In this lecture, we discuss transverse coherent oscillations for cases where the fields induced by the beam have a long memory providing multibunch or resonant instabilities. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1420422

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

After its discovery in 1969 by C. Pellegrini and M. Sands, the head-tail instability was recognized around the world as one of the most important effects limiting single-bunch currents in storage rings. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1420423

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

Outlines of bunch-by-bunch feedback systems for suppressing multibunch instabilities in electron/positron storage rings are shown. The design principles and functions of the feedback components are reviewed. The application of the feedback system as a tool to analyze instabilities using transient-domain techniques is also shown. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1420424

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

The space-charge effects in a straight beamline are considered. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1420425

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

Space-charge effects in a circular accelerator are discussed, with emphasis on self-consistent treatment. After we review some basic aspects of space-charge effects, we describe observations, cures, and simulation methods. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1420426

出版商:AIP    

年代:1901

数据来源: AIP