Year: 2026
Type: preprint
Abstract: Radio pulsars can power their coherent radio emission through intermittent plasma discharges in magnetospheric gaps. The nonlinear coupling between particle acceleration, quantum electrodynamic (QED) processes, and electric field screening remains difficult to model self-consistently. We present an analytical concurrency model and first-principles particle-in-cell (PIC) simulations of polar cap discharges. The model predicts limit-cycle behavior where the electric field and plasma density oscillate with a frequency set by the local plasma frequency, modified by the plasma inertia. One-dimensional simulations with exact QED rates and realistic plasma parameters validate these predictions. The discharges generate pair multiplicities up to $M_\pm \sim 10^4$ and excite electric field oscillations with spectra consistent with pulsar radio microstructure. These results provide a theoretical framework connecting microphysical gap dynamics to macroscopic observables.
Source: arXiv (Cornell University)
Authors: Nättilä, Joonas, Salmi, Tuomo
Institution: University of Helsinki
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funder: European Commission
OpenAlex ID: W7204213725