Transition Wake-Fields in Resistive Tube.pdfVIP

TRANSITION WAKE-FIELDS IN RESISTIVE TUBE M. Ivanyan, V. Tsakanov Center for the Advancement of Natural Discoveries using Light Emission - CANDLE Acharyan 31, Yerevan, 375040, Armenia A. Tsakanian Yerevan State University, Alek Manukyan 1, Yerevan, 375025, Armenia Abstract The transition wake fields excited by relativistic point charge in cylindrical resistive round pipe are studied. The problem has been solved for the infinite pipe with abrupt change of the walls conductivity from perfect boundary condition to resistive. The analytical presentation of the longitudinal monopole wake field is given. INTRODUCTION The development of the physics of ultra-short, ultra-low emittance relativistic electron beams drives to the necessity of exact derivation of the wake fields induced by point charge during the interaction with its environment. Although large number of such electro-dynamical problems in steady state regime have been well understood and derived in the terms of the structure impedance and wake potentials [1,2], the transition effects in some cases are still missed from the general picture. The importance of the knowledge on the transition behavior of the excited fields is driven also by both better understanding of physical processes and the proper application of the numerical codes to evaluate the excited fields in real structure. The radiation excited by the relativistic charged particle in the infinite round pipe with finite conductivity wall material is presented in number of Refs. [1-6]. The impedance of finite length resistive tube has been derived in Refs. [7,8]. In this paper, the study of the longitudinal transition wake fields in resistive tube is given. The explicit presentation for the transient wake fields is given when the charge travels along the axis of cylindrically symmetric resistive pipe. It is shown that the characteristic distance [1,5] used in resistive wake field derivation defines the typical transit