The RDDS (Rounded Damped Detuned Structure) accelerator damps the transverse wakefield excited by bunches of electrons traversing thousands of linear accelerator structures. Errors in the fabrication of the cells which constitute each structure can result in a wakefield which is resonantly driven by the bunches, leading to BBU (Beam Break Up) and to a substantial growth in the beam emittance. O...

The passage of a multi-bunch beam through an X-band accelerator with cells and structures misaligned gives rise to wakefields which disrupt succeeding bunches. As a consequence, there is growth in the overall emittance of the final colliding bunches. Here we study this process in the context of a JLC-NLC which employs the recently developed RDDS (Rounded Damped Detuned Structures) accelerators ...

In the present paper, the problem of low-velocity impact of an elastic sphere against a viscoelastic Timoshenko-type beam is studied considering the extension of its middle surface. The viscoelastic features of the beam out of the contact domain are governed by the standard linear solid model with derivatives of integer order, while within the contact domain the fractional derivative standard l...

The world’s first dedicated source for synchrotron radiation, the Synchrotron Radiation Source (SRS) at Daresbury, UK is now 20 years old. During its operational lifetime, the control and stability of the electron and photon beams have been significantly improved, to ensure continued reliable operation, in order to necessitate various lattice and insertion device (ID) upgrades [1][2]. The SRS c...

Abstract An asymptotic perturbation solution for a linear oscillator of free damped vibrations in fractal medium described by local fractional derivatives was obtained Yang and Srivastava (Commun Nonlinear Sci Numer Simul 29(1–3):499–504, 2015). In this paper, we obtain the numerical forced problems employing operational matrix integration Bernoulli orthonormal polynomials. The is determined wi...

A numerical solution for neutral delay fractional order partial differential equations involving the Caputo derivative is constructed. In line with this goal, drift term and time are discretized by a finite difference approximation. The energy method used to investigate rate of convergence unconditional stability temporal discretization. interpolation moving Kriging technique then approximate s...

Plans for the next generation of electron-positron colliders (B-factories and B-factory-like machines) call for high beam currents to produce luminosities of the order of 1033. To store these high currents in a machine, special attention must be paid to the interaction of the beam with discontinuities in the surrounding vacuum chamber. RF cavities are among the biggest perturbations in accelera...

We find that in a two-level system there are two kinds of four-wave mixing processes which destructively contribute to the third-order nonlinear susceptibility. In a paired-photon generation scheme by using a single retroreflected pump beam, these two processes occur with definite time orders. The biphoton temporal correlation, which is measured with a back-to-back geometry in a laser-cooled tw...