Driver Accelerator Design for the 10 KW upgrade of the Jefferson Lab IR FEL

An upgrade of the Jefferson Lab IR FEL [1] is now under construction. It will provide 10 kW output light power in a wavelength range of 2--10 {micro}m. The FEL will be driven by a modest sized 80--210 MeV, 10 mA energy-recovering CW superconducting RF (SRF) linac. Stringent phase space requirements at the wiggler, low beam energy, and high beam current subject the design to numerous constraints. These are imposed by the need for both transverse and longitudinal phase space management, the potential impact of collective phenomena space charge, wakefields, beam break-up (BBU), and coherent synchrotron radiation (CSR), and interactions between the FEL and the accelerator RF system. This report addresses these issues and presents an accelerator design solution meeting the requirements imposed by physical phenomena and operational necessities.