Jan Botman | Search arXiv

arXiv2003

Transverse self-interactions within an electron bunch moving in an arc of a circle (generalized)

Transverse self-interactions within a "line" bunch of electrons moving in an arc of a circle have been studied extensively by us from an electrodynamical viewpoint. Here we treat an electron bunch with a given vertical (i.e. perpendicular to the orbital plane) size by a generalization of our previous work to the case of a test particle with vertical displacement interacting with a line bunch. In fact, since a bunch with vertical extent can always be thought of as a superposition of displaced charge lines, all the relevant physical aspects of the problem are included in the study of that simple model. Our generalization results in a physically meaningful and quantitative explanation of the simulations obtained with the code $TraFiC^4$ as well as in successful cross-checking of the code.

physics.acc-ph↗

arXiv2002

Transverse self-fields within an electron bunch moving in an arc of a circle

As a consequence of motions driven by external forces, self-fields (which are different from the static case) originate within an electron bunch. In the case of magnetic external forces acting on an ultrarelativistic beam, the longitudinal self-interactions are responsible for CSR (Coherent Synchrotron Radiation)-related phenomena, which have been studied extensively. On the other hand, transverse self-interactions are present too. At the time being, existing theoretical analysis of transverse self-forces deal with the case of a bunch moving along a circular orbit only, without considering the situation of a bending magnet with a finite length. In this paper we propose an electrodynamical analysis of transverse self-fields which originate, at the position of a test particle, from an ultrarelativistic electron bunch moving in an arc of a circle. The problem will be first addressed within a two-particle system. We then extend our consideration to a line bunch with a stepped density distribution, a situation which can be easily generalized to the case of an arbitrary density distribution. Our approach turns out to be also useful in order to get a better insight in the physics involved in the case of simple circular motion and in order to address the well known issue of the partial compensation of transverse self-force.

physics.acc-ph↗