Thermal wave model for nonlinear longitudinal dynamics of a relativistic charged particle bunch in cold plasmas

We study the longitudinal dynamics of a relativistic charged particle bunch through a cold, unmagnetized plasma, within the framework of the recently proposed thermal wave model for relativistic charged particle beam propanation. We show that, under the action of both a purely electrostatic plasma wave potential well and the plasma wake potential (self-interaction), the longitudinal bunch dynamics is governed by a nonlinear Schrodinger equation for a complex wave function whose squared modulus is proportional to the longitudinal bunch density. This wave model, for which the diffraction parameter is represented here by the longitudinal emittance, allows us to study synchrotron-like oscillations in the plasma wave potential well as well as to obtain a longitudinal envelope equation which includes the self-interaction. Furthermore, we show that a soliton solution for the bunch density is possible and it results to be the natural asymptotic evolution of a modulational instability occurring when the bunch propagates in the plasma under the action of the self-force only

Wake fields and impedance

Knowledge of the electromagnetic interaction between a beam and the surrounding vacuum chamber is necessary in order to optimize the accelerator performance in terms of stored current. Many instability phenomena may occur in the machine because of the fields produced by the beam and acting back on itself as in a feedback device. Basically, these fields produce an extra voltage and energy gain, affecting the longitudinal dynamics, and a transverse momentum kick which deflects the beam. In this paper we describe the main features of this interaction with typical machine components.Knowledge of the electromagnetic interaction between a beam and the surrounding vacuum chamber is necessary in order to optimize the accelerator performance in terms of stored current. Many instability phenomena may occur in the machine because of the fields produced by the beam and acting back on itself as in a feedback device. Basically, these fields produce an extra voltage and energy gain, affecting the longitudinal dynamics, and a transverse momentum kick which deflects the beam. In this paper we describe the main features of this interaction with typical machine components

Bunched beams in axisymmetric systems

We analyse, in this paper, the self field of a bunched beam in a cylindrical metallic pipe with arbitrary density. The field is calculated by superposition of the Green's functions of the single charge in the pipe. A general solution is given as a Bessel-Fourier expansion, which is characterised by very good convergence properties. This allows the evaluation of the dynamics of a large class of physical beams by using this kind of solution for the self field. As an example the field is calculated for the case of a parabolic radial and elliptic longitudinal density profile

Some integral formulations occuring in accelerator physics

Consiglio Nazionale delle Ricerche (CNR). Biblioteca Centrale / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

Bunched beams in axisymmetric systems

Submitted to Il Nuovo Cimento BConsiglio Nazionale delle Ricerche (CNR). Biblioteca Centrale / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

Coaxial wire technique: a comparison between theory and experiment

Submitted to Il Nuovo Cimento BConsiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7 Rome / CNR - Consiglio Nazionale delle RichercheSIGLEITItal