Based on the nonlocal Timoshenko beam theory, the dynamic stability of functionally gradded (FG) nanoeams under axial load is studied in thermal environment, with considering surface effect. It is used power law distribution for FGM and the surface stress effects are considered based on Gurtin-Murdoch continuum theory. Using Von Karman geometric nonlinearity, governing equations are derived bas...

A short, intense particle beam can drive a very large amplitude plasma wave or wakefield. The longitudinal component of the wakefield results in energy loss of the bulk of the beam and gain of the particles in the beam tail. First, a systematic investigation of the longitudinal fields excited in a plasma by a short, dense beam of electrons or positrons is carried out using two-dimensional, cyli...

BACKGROUND Intrafractional motion results in local over- and under-dosage in particle therapy with a scanned beam. Scanned beam delivery offers the possibility to compensate target motion by tracking with the treatment beam. METHODS Lateral motion components were compensated directly with the beam scanning system by adapting nominal beam positions according to the target motion. Longitudinal ...

081002-1 The interaction between a low-density electron cloud in a circular particle accelerator with a circulating charged particle beam is considered. The particle beam’s space charge attracts the cloud, enhancing the cloud density near the beam axis. It is shown that this enhanced charge and the image charges associated with the cloud charge and the conducting wall of the accelerator may hav...

In this paper, by using an analogy among quantum mechanics, electromagnetic beam optics in optical fibers, and charge particle beam dynamics, we introduce the concept of coherent states for charged particle beams in the framework of the Thermal Wave Model (TWM). We give a physical meaning of the Gaussian-like coherent structures of charged particle distribution that are both naturally and artif...

A generation of halo particles and an emittance growth are investigated numerically for a highcurrent beam transport during a longitudinal bunch compression. The halo particles are generated during the drift compression with an alternating gradient confinement lattice in the transverse direction. The emittance growth is caused by the halo particle generation, and depends on the drift length for...

In this paper airflow, nano-and micro-particle motions in an aerodynamic particle beam focusing system consisting of several lenses, a nozzle and the downstream chamber, was studied. A three-dimensional numerical simulation for the system was presented and the compressible airflow and thermal conditions in the aerodynamic lens system were evaluated. Dilute particle concentration was assumed so ...

In this paper, simulation codes for Beam Delivery Systems in linear colliders are discussed. Several tracking codes are available for particle tracking. They do not normally include precise calculation of the beam-beam effect, with accounting for pinch, hour-glass, pair production. They provide instead the particle distributions at the interaction point, after tracking through the different com...