Title: Wide Bandwidth, Frequency Modulated Free Electron Laser,
Abstract: It is shown via theory and simulation that the resonant frequency of a Free
Electron Laser may be modulated to obtain an FEL interaction with a frequency
bandwidth which is at least an order of magnitude greater than normal FEL
operation. The system is described in the linear regime by a summation over
exponential gain modes, allowing the amplification of multiple light
frequencies simultaneously. Simulation in 3D demonstrates the process for
parameters of the UK's CLARA FEL test facility currently under construction.
This new mode of FEL operation has close analogies to Frequency Modulation in a
conventional cavity laser. This new, wide bandwidth mode of FEL operation
scales well for X-ray generation and offers users a new form of high-power FEL
output.