Magnetic mirror cavities as THz radiation sources and a means of   quantifying radiation friction
  We propose a radiation source based on a magnetic mirror cavity. Relativistic electrons are simulated entering the cavity and their trajectories and resulting emission spectra are calculated. The uniformity of the particle orbits is found to result in a frequency comb in terahertz range, the precise energies of which are tuneable by varying the electron's $\gamma$-factor. For very high energy particles radiation friction causes the spectral harmonics to broaden and we suggest this as a possible way to verify competing classical equations of motion. 
Amol R. Holkundkar, Chris Harvey
physics.optics physics.class-ph