Photon Acceleration in Magnetized Plasma: A Mechanism for Fast Radio Bursts

We propose a mechanism for fast radio bursts based on photon acceleration by relativistic shocks propagating through highly magnetized electron–positron plasmas, as expected in magnetar magnetospheres. Density modulations at the shock front create relativistically moving refractive-index perturbations that transform low-frequency electromagnetic precursors into amplified high-frequency radiation. We show that the predicted frequencies, durations, and energetics of the resulting fast radio bursts are consistent with the magnetic-field strengths, shock Lorentz factors, and characteristic spatial scales expected in magnetar magnetospheres.