Coherent synchrotron radiation and microbunching in bunch compressor.

Coherent synchrotron radiation (CSR) is of great interest to those designing accelerators as drivers for free-electron lasers (FELs) and energy recovery linacs (ERLs). A growing body of experimental evidence indicates the potentially serious impact of CSR on beam quality as we attempt to create high-brightness, high-current electron bunches using magnetic compression techniques. It is not an over-statement to say that the success of FEL and ERL projects could well depend on how well CSR is understood in the design phase. Simulation codes typically show qualitative or rough quantitative agreement with experiments, indicating that our understanding of the physics is improving but incomplete. For example, an unexpected microbunching instability was recently discovered with the code ''elegant'' and is now the subject of intense theoretical work. This paper presents an overview of CSR issues, including recent simulation results on the CSR instability. Experimental results and issues are also discussed