Description
Betatron radiation is a synchrotron-like x-ray source produced in laser wakefield accelerators (LWFA) through the transverse oscillation of relativistic electrons in the strong focusing fields of a plasma wave. As electrons are injected into and accelerated by the plasma wave, they undergo oscillations while simultaneously gaining energy, emitting broadband radiation in the x-ray regime.
Unlike conventional synchrotron radiation, betatron emission in LWFA arises from electron populations with an evolving energy distribution, leading to a temporally and spectrally broadened x-ray spectra. This makes modelling of betatron radiation particularly challenging.
This work explores the theoretical and computational modelling of betatron emission in LWFA. Emphasis is placed on the connection between electron dynamics and the resulting radiation spectrum, as well as on the limitations of commonly used analytical approximations. Numerical approaches are discussed as a method for capturing the physics of the emission process and the key challenges in linking simulation outputs to experimentally measurable quantities.