摘要:

We solve the Vlasov equation for the longitudinal distribution function and find stationary wave patterns when the distribution in the energy error is Maxwellian. In the long wavelength limit a stability criterion for linear waves has been obtained and a Korteweg-de Vries-Burgers equation for the relevant hydrodynamic quantities has been derived. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1301899

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

Space-charge impedance calculations for smooth vacuum chambers with an arbitrary cross-section and perfectly conducting walls are considered in the long-wavelength approximation, when&ohgr;b/(&bgr;&ggr;c)≪1,wherebis a typical transverse size. For the SNS beam energies&bgr;&ggr;⩽1.8,and the wavelengths are long when&lgr;≫b.Within the long-wavelength approximation, the fields can be found by solving a 2-D electrostatic problem. Two examples are presented: the space-charge impedance of screening wires (RF-cage) and of a ceramic chamber with inner metal stripes. In addition, we explore the transverse space-charge impedance of a circular pipe with account of betatron oscillations in a wide frequency range. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1301900

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

Phase modulation (PM) is used to increase the current limit in the IPNS RCS. A device referred to as a scrambler introduces a small oscillating phase between the two RCS rf cavities at approximately twice the synchrotron frequency,fs.The modulation introduced by the scrambler generates longitudinal oscillations in the bunch at2fs.Modulations in the bunch are also observed transversely indicating a coupling between longitudinal and transverse motion. Comparing PM with amplitude modulation (AM), coupling to the beam is roughly equivalent at2fs.©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1301901

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

Simple comments are given on the mechanism of e-p multipactoring. We emphasize that beam instability is a factor which may be important for this effect. The comments are results of the discussion which authors have during the Workshop. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1301902

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

The impedance working group was charged to reply to the following 8 questions relevant to the design of high-intensity proton machines such as the SNS or the FNAL driver. These questions were first discussed one by one in the whole group, then each ne of them assigned to one member to summarize. On the lst morning these contributions were publicly read, re-discussed and re-written where required—hence they are not the opinion of a particular person, but rather the averaged opinion of all members of the working group. (AIP)

ISSN:0094-243X    

DOI:10.1063/1.1301903

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

There are a number of new high intensity proton synchrotrons proposed: the SNS at Oakridge and ESS in Europe, as neutron sources; the JHF/NSP in Japan, a multi-disciplinary facility sponsored by KEK and JAERI; the New FNAL Booster; and the Proton Driver as first stage of a&mgr;−&mgr;collider. In addition there are operating machines such as ISIS at RAL, the Brookhaven AGS and its Booster, and the IPNS at Argonne with high intensity and beam power. Moreover, at the energy frontier the beam quality requirements of CERN LHC will pose new and challenging operation modes for its injector chain comprising Booster, PS, and SPS. All will encounter beam current limitations arising from beam instability; and the lower energy machines are also limited by space-charge collective effects. Though many anticipated problems are shared in common between these machines, the impetus for the theme of this workshop, “Instabilities of High Intensity Hadron Beams in Rings”, comes from the SNS and Proton Driver which were the inspiration for the charge to the “Instabilities Working Group” to answer the following questions. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1303088

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1301904

出版商:AIP    

年代:1999

数据来源: AIP