Ph.D Thesis

Ph.D StudentBanna Samer
SubjectScaling-Laws of Wake-Fields in Optical Structures
DepartmentDepartment of Electrical and Computer Engineering
Supervisors PROF. Levi Schachter
PROFESSOR EMERITUS David Schieber (Deceased)


Analysis of wake-fields generated by moving charges in the vicinity of dielectric and metallic bodies is essential for the design of the next generation of optical acceleration structures. Such an analysis contributes to the evaluation of the deceleration force and enables to determine the impact of beam characteristics and geometrical parameters of the structures on the wake-field.

Future optical acceleration structures are very different from the metallic symmetric structures used so far in the microwave range; it is therefore necessary to investigate a variety of topics that, while being well known for microwave acceleration structures are almost unknown in the optical range. The purpose of this research is to develop some scaling-laws of wake-fields in optical structures in order to explore the following issues: a) the effect of the radius of curvature of a dielectric body on the motion of charges moving in its vicinity; b) decelerating force acting on moving charges approaching a geometrical discontinuity; c) properties of wake-fields due to surface roughness in optical structures; d) frequency dependence of dielectric coefficients. The relevant scaling-laws obtained in such a research may assist in the design of future optical acceleration structures. 

Among the issues mentioned above, the wake-fields associated with three simple models were investigated. For example, the effect of the radius of curvature is addressed, where the radiation characteristics generated by a relativistic line charge moving in the vicinity of a dielectric cylinder are explored. Moreover, a time-domain solution for the wake-field of an electron bunch moving approaching a geometrical discontinuity is obtained. In addition, surface roughness effects on a moving electron bunch are examined.