Nonlinear Phenomena in Complex Systems, 2026, Vol.29, No.2, pp.181

NONLINEAR PHENOMENA IN COMPLEX SYSTEMS
An Interdisciplinary Journal

2026, Vol.29, No.2, pp.181 - 186

Self-focusing of Ultrarelativistic Electron Wave Packets in Collision-free Plasma

Nguyen Quang San and I. D. Feranchuk

This work investigates a novel physical effect: the self-focusing of ultrarelativistic electron wave packets propagating through a collision-free plasma. By employing a linearized approach to the coupled Dirac and Vlasov equations, we derive the dispersion relations governing the beam's stability. Our analysis identifies the conditions under which the imaginary part of the frequency becomes positive, leading to an exponential contraction of the beam diameter. We characterize this effect by providing an analytical expression for the self-focusing length L_c and performing numerical estimates for characteristic experimental parameters. The results suggest that for a 1 GeV electron beam, this self-focusing effect can occur within a distance of approximately 10 cm in a typical laboratory plasma.

Key words: ultrarelativistic electron beams, self-focusing, collision-free plasma, Lorentz gauge, plasma-beam interaction

DOI: https://doi.org/10.5281/zenodo.21106270

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