ISBN 978-3-8439-0647-0

978-3-8439-0647-0, Reihe Physik

Marit Klein
Optics Calculations and Simulations of Longitudinal Beam Dynamics for the Low-α Mode at ANKA

103 Seiten, Dissertation Karlsruher Institut für Technologie (2012), Softcover, A5

Zusammenfassung / Abstract

The synchrotron light source ANKA at the Karlsruhe Institute of Technology (KIT) is frequently operated in short bunch mode to produce intense coherent synchrotron radiation (CSR) in the THz range. To obtain small bunch lengths, dedicated magnet optics with a low momentum compaction factor were developed. In this thesis, the modeling of five different of these, so-called low-alpha optics, is presented. Extensive optics calculations as well as the determination of the model and instrumentation limits are discussed in detail. This preparatory work provides the basis for the following simulations of the longitudinal electron dynamics under the influence of the CSR induced short range selffields. A new impedance model is derived, allowing for long range bunch-to-bunch interaction, which increases the overall electric field acting on the single electrons. These cumulated fields lead to a decreased current threshold for the occurring microbunching instability and different beam dynamics compared to single bunch studies, as seen in the ANKA storage ring. For the first time, this bunch-to-bunch interaction could be simulated using a Vlasov-Solver and the result are compared with short bunch experiments at ANKA.