Electron Acceleration in Ion Channels Induced by Linearly Chirped Gaussian and Laguerre-Gaussian Laser Pulses: A Theoretical Comparison

We present a theoretical study of chirp-controlled electron acceleration in preformed ion channels. Two laser drivers are compared: a fundamental Gaussian pulse and a Laguerre-Gaussian (LG) pulse carrying orbital angular momentum (OAM). Electron dynamics are computed from the normalised relativistic Maxwell–Lorentz equations. Linear frequency chirp is applied to both beam types to examine its effect on phase synchronism, electron trapping, and energy gain. Chirp improves resonance stability and electron-field coupling for both drivers. LG pulses, however, consistently outperform Gaussian pulses. They yield higher peak energies, higher trapping efficiency, and stronger transverse confinement. This advantage arises from two combined effects: chirp-induced phase modulation and the OAM of the LG field. Together, these effects modify electron trajectories and enhance energy transfer. We identify a chirp-dependent acceleration mechanism unique to LG beams. This mechanism has no counterpart in the Gaussian case. It produces a chirpinduced energy enhancement of approximately 22% for LG beams, compared to 15% for Gaussian beams, at a 0 = 15. With ion-channel focusing included, the LG beam’s maximum energy gain exceeds the unchirped Gaussian case by more than a factor of two. These results demonstrate that combining spatial beam structuring with temporal chirp control provides a distinct route to enhanced electron acceleration in compact, laser-driven accelerator schemes.