Beam Loading and Higher-band Longitudinal Wakes in High Phase Advance Traveling Wave Accelerator Structures for the Glc/nlc

A multi-bunch beam, traversing travelling wave accelerator structures, each with a 5π/6 phase advance per cell, is accelerated at a frequency that is synchronous with the fundamental mode frequency. As per design, the main interaction occurs at the working frequency of 11.424 GHz. However, modes with frequencies surrounding the dominant accelerating mode are also excited and these give rise to additional modal components to the wakefield. Here, we consider the additional modes in the context of X-band accelerator structures for the GLC/NLC (Global Linear Collider/Next Linear Collider). Finite element simulations and field mode-matching models are employed in order to calculate the wakefield. Paper presented at the 2004 9th European Particle Accelerator Conference (EPAC 2004) Lucerne, Switzerland 5 9 July 2004 This work is supported by Department of Energy grant number DE-AC03-76SF00515 BEAM LOADING AND HIGHER-BAND LONGITUDINAL WAKES IN HIGH PHASE ADVANCE TRAVELING WAVE ACCELERATOR STRUCTURES FOR THE GLC/NLC R.M. Jones, V.A. Dolgashev, Z. Li, and T.O. Raubenheimer; SLAC, USA Abstract A multi-bunch beam, traversing travelling wave accelerator structures, each with a 5π/6 phase advance per cell, is accelerated at a frequency that is synchronous with the fundamental mode frequency. As per design, the main interaction occurs at the working frequency of 11.424 GHz. However, modes with frequencies surrounding the dominant accelerating mode are also excited and these give rise to additional modal components to the wakefield. Here, we consider the additional modes in the context of X-band accelerator structures for the GLC/NLC (Global Linear Collider/Next Linear Collider). Finite element simulations and field mode-matching models are employed in order to calculate the wakefield.A multi-bunch beam, traversing travelling wave accelerator structures, each with a 5π/6 phase advance per cell, is accelerated at a frequency that is synchronous with the fundamental mode frequency. As per design, the main interaction occurs at the working frequency of 11.424 GHz. However, modes with frequencies surrounding the dominant accelerating mode are also excited and these give rise to additional modal components to the wakefield. Here, we consider the additional modes in the context of X-band accelerator structures for the GLC/NLC (Global Linear Collider/Next Linear Collider). Finite element simulations and field mode-matching models are employed in order to calculate the wakefield.