Plasma-astrophysical Mechanism as a Probe to Unravel the Nature of Polarized Pulsar Radio Emission

Abstract Despite numerous theories on pulsars, a consensus on a reliable emission mechanism explaining their diverse observational characteristics remains elusive. In this paper, we couple the plasma process of stimulated Raman scattering (SRS) with the emission geometry of radio pulsars. SRS, involving energy transfer from curvature radiation photons to weakly damped electron-plasma modes, allows us to simulate integrated pulse profiles. We compute the growth rate of plasma modes across phase factors and reproduce soliton pulse profiles using nonlinear Schrödinger equations, driven by the pondermotive force in a typical plasma environment. We also examine collisional damping across plasma species. Notably, we show that circular polarization (CP) decreases with lower nonlinear parameter η (density perturbation ratio along two orthogonal basis vectors in our synergy). A similar problem was addressed via Bayesian analysis of magnetar radio emission data in Nature Astronomy; our approach offers a theoretical explanation using a plasma-astrophysical-based mechanism. We argue that SRS can explain various pulsar phenomena, including polarization angle swing reversals, percentage changes in circular and linear polarization nature, and depolarization.