Nonlinear scaling of photon radiation power in relativistic plasma current filamentation instability with beam parameters

We investigate in this work the photon radiation of relativistic electron beams in the magnetic fields induced by plasma current filamentation instability. An analytical model is proposed, and the radiated power is shown to depend only on the beam density, charge, and energy. The radiated power in the beam–plasma system increases significantly in the linear stage of the instability due to beam filament merger and becomes saturated in the nonlinear stage. Detailed electromagnetic particle-in-cell simulations are performed and the nonlinear scalings of the radiated power with beam parameters are found, showing good agreement with the analytical model.