Accelerator Physics Challenges in Future Linear Colliders

At the present time, there are a number of future linear collider designs with a center-of-mass energy of 500 GeV or more with luminosities in excess of 10 cm 2 s . Many of these designs are at an advanced state of development. However, to attain the high luminosity, the colliders require very small beam emittances, strong focusing, and very good stability. In this paper, some of the outstanding issues related to producing and maintaining the small beam sizes are discussed. Although the di erent designs are based very di erent rf technologies, many of these problems are common. Invited paper presented at the 1999 Particle Accelerator Conference, New York, NY, March 28{April 2, 1999 Work supported by Department of Energy contract DE{AC03{76SF00515. Accelerator Physics Challenges in Future Linear Colliders T.O. Raubenheimer Stanford Linear Accelerator Center, Stanford University, Stanford, CA, 94309