A Review of New Manifestations of Collective Effects

The design of high performance `factories', large hadron colliders and synchrotron light sources calls for a large number of high intensity bunches. This imposes feedback systems and a tight impedance budget to control conventional instabilities, some of which are differently emphasised depending on the ongoing evolution of beam parameters. Ion trapping, for example, is no longer reported as a problem for the new generation of very low emittance electron storage rings. However new mechanisms appear, such as the fast ion instability for electron beams and the build-up of electron clouds for positron or proton beams. We review these new manifestations of collective phenomena, essentially related to the single-pass interaction of a bunch train with foreign or `gaijin' particles, and discuss their dependence on several machine parameters such as bunch intensity and spacing. We also summarise possible cures and positive as well as negative experimental evidence in existing accelerators

Electron Cloud in the LHC

A theoretical and experimental crash program has been set up at CERN to investigate electron cloud effects in the LHC. In particular, I report about recent estimates of the critical secondary-emission yield, versus bunch population and bunch spacing, and ongoing multipacting tests with a coaxial resonator in a strong magnetic field

Resistive wall impedance as derivative of the electric capacitance for a beam pipe of arbitrary cross section

We derive a general formula expressing the resistive wall impedance in the ultrarelativistic limit for a beam pipe of arbitrary cross section through the 'normal derivative' of its electric capacitance. An application to the case of rectangular cross secrion yields a closed form of expression of the corresponding longitudinal impedance in terms of elliptic integrals

High Luminosity Issues for DAPhNE Upgrade

We give an overview of presentations and discussions during the Accelerator Working Group Session dedicated to High Luminosity Issues for a future upgrade of the Frascati e+e- Phi-Factory DAPhNE at the Workshop "e+e- in the 1-2 GeV range: Physics and Accelerator Prospects" held at Alghero (Italy) on 10-13 September 2003.Comment: Invited talk at the Workshop on e+e- in the 1-2 GeV range, Alghero, Italy, September 2003 (eConf c0309101

Summary of the Workshop on Beam-Beam effects in Large Hadron Colliders (LHC99)

The beam-beam interaction can limit the performance of hadron colliders such as the LHC and has to be taken into account during the design of the accelerator. A workshop was held at CERN from 12 to 16 April 1999 to review the current knowledge and experience and to discuss ongoing and future studies. The contributions and details of the discussion and the summaries are compiled in the proceedings of the workshop [1]. While these proceedings are a working document for further studies, this report intends to give an overview of the main problems and provides the interested but non-specialised reader with a survey of the critical issues, together with the proposed solutions and studies

Summary of session 2: high intensity effects

The CARE-HHH-APD workshop LHC-LUMI-05 on Scenarios for the LHC Luminosity Upgrade was held in Arcidosso, Italy, from August 31st to September 3rd, 2005. The workshop was organized in four plenary morning sessions supported by afternoon sessions of two parallel working groups on LHC IR Upgrade and High Energy Injectors. In this report we review the presentations and discussions in Session 2, devoted to High-Intensity Effects, emphasizing the suggestions for future studies and pointing out the open issues