Impedance Description of Coherent Synchrotron Radiation with Account of Bunch Deformation

Technical Report · Tue Jan 25 04:00:00 EST 2005

DOI:https://doi.org/10.2172/839759· OSTI ID:839759

Warnock, R ^[1]

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1. SLAC

We are concerned with coherent longitudinal motion in a storage ring, especially with situations in which coherent synchrotron radiation (CSR) can influence stability of the beam. The collective force from CSR is usually described by an impedance or a wake function in such a way that the force depends only on the charge distribution at the present time. This description is exact only for a rigid bunch, since causality demands that the force depend on the prior history of the bunch. We show how to treat a deforming bunch by applying the ''complete impedance'' Z(n,w), a function of wave number and frequency. We derive this impedance and study its analytic properties for a special model: radiation from circular orbits shielded by parallel plates representing the metallic vacuum chamber. We analyze the corresponding collective force, obtaining the usual formula as a first approximation, plus easily computed corrections that depend on present and prior values of the time derivative of the charge density. In related papers we have applied these results in numerical simulations of instabilities induced by CSR.

• Research Organization: Stanford Linear Accelerator Center (SLAC), Menlo Park, CA
• Sponsoring Organization: SC
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 839759
• Report Number(s): SLAC-PUB-10995
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
CAUSALITY
CHARGE DENSITY
CHARGE DISTRIBUTION
DEFORMATION
IMPEDANCE
PLATES
RADIATIONS
STABILITY
STORAGE RINGS
SYNCHROTRON RADIATION