Advanced Modeling Tools for Optimizing Tapering Schemes in X-Ray Free-Electron Lasers

Future generations of X-ray free-electron lasers will use novel seeding and tapering schemes to extract power from the electron beams with orders of magnitude greater efficiency. The current state-of-the-art free-electron laser codes are not adequately equipped for designing these machines. By developing a new code with these schemes in mind, a new generation of machines can be studied with high fidelity. Tapering schemes require control of all the undulator parameters – both the period and the field strength – and self-seeding schemes require detailed information about the longitudinal phase space. A hybrid Vlasov-macroparticle code that uses a single undulator period as the fundamental unit will allow high fidelity simulations of any advanced tapering or phase space schemes for future free-electron lasers. A hybrid Vlasov-macroparticle model will be implemented in an open source framework and benchmarked against existing codes. This model will then be wrapped in a nonlinear optimizer to work towards improving the efficiency of tapering schemes for advanced free-electron laser designs. Commercial Applications and Other Benefits Advanced modeling tools for optimizing complex designs are required for many science and engineering applications. The success of developing a hybrid Vlasov-macroparticle code for describing a complicated device such as a strongly tapered, high efficiency free-electron laser can be leveraged into consulting with private companies such as Department of Defense Prime contractors.