Long-Range Resonant Wakefields at High Group Velocity
نویسندگان
چکیده
* The work is supported by DOE SBIR No. DE-FG03-96ER82213. Abstract Synchronous wakefields in a dispersive waveguide are formulated in a general form. The fundamental role of group velocity in wakefield propagation, calculation of attenuation, amplitudes, form-factors and loss-factors is demonstrated for single-bunch and multi-bunch train. Waveguide adiabatic tapering and bunch density variations are taken into account analytically in the timedomain. Application of this approach to oversized pipe with small corrugations and roughness is discussed.
منابع مشابه
Long-Range Wakefields and Split-Tune Lattice at the SLC
At the SLC, a train consisting of one positron bunch fo l lowed by two electron bunches is accelerated in the linac, each separated by about 60 ns. Long-range transverse wakef ields from the leading bunch were found to cause up to a factor o f three increase in beam jitter for the trailing bunches. Incoming jitter is efficiently damped by BNS damping, but excitations in the middle of the linac ...
متن کاملEmittance Dilution Simulations for Normal Conducting and Superconducting Linear Colliders
Abstract An electron (or positron) multi-bunch train traversing several thousand accelerator structures can be distorted by the long-range wakefields left behind accelerated bunches. These wakefields can at the very least, give rise to a dilution in the emittance of the beam and, at worst can lead to a beam break up instability. We investigate the emittance dilution that occurs for various freq...
متن کاملManifold Damping of Wakefields in High Phase Advance Linacs for the Nlc
Earlier RDDS (Rounded Damped Detuned Structures) [1,2], designed, fabricated and tested at SLAC, in collaboration with KEK, have been shown to damp wakefields successfully. However, electrical breakdown has been found to occur in these structures and this makes them inoperable at the desired gradient. Recent results [3] indicate that lowering the group velocity of the accelerating mode reduces ...
متن کاملRoom Temperature Accelerator Structures for Linear Colliders*
Early tests of short low group velocity and standing wave structures indicated the viability of operating Xband linacs with accelerating gradients in excess of 100 MeV/m. Conventional scaling of traveling wave traveling wave linacs with frequency scales the cell dimensions with λ. Because Q scales as λ, the length of the structures scale not linearly but as λ in order to preserve the attenuatio...
متن کاملNumerical Studies on Locally Damped Structures
In the JLC/NLC X-band linear collider, it is essential to reduce the long-range dipole wakefields in the accelerator structure to prevent beam break up (BBU) and emittance degradation. The two methods of reducing the long-range wakefields are detuning and damping. Detuning reduces the wakefields rapidly as the dipole modes de-cohere but, with a finite number of modes, the wakefield will grow ag...
متن کامل