Solar Magnetic Switchbacks Produced by Magnetized Coulomb Scattering between Galactic Cosmic Rays and Solar Radiation
Abstract
Magnetic switchbacks contribute significantly to coronal heating and the acceleration of the solar wind. In this study, they are considered a weakly collisional plasma phenomenon influenced by the magnetic-field configuration rather than a process arising solely from electrostatic Coulomb collisions. The proposed mechanism involves magnetic scattering associated with interactions between low-energy Galactic Cosmic Rays (GCRs; 3–30 MeV/nuc) and solar radiation. These interactions are considered to become more pronounced during periods of enhanced solar activity, including the release of Solar Energetic Particles (SEPs). Within this framework, highly modulated GCRs interacting weakly with solar radiation are proposed to generate magnetic switchbacks through a form of anti-Stokes Raman-like scattering. This process transfers energy within the magnetized plasma, thereby contributing to plasma heating and solar-wind acceleration. The interaction is nonlinear and non-isotropic, with the external magnetic field modifying charged-particle dynamics and producing characteristic S-shaped trajectories. In the presence of a strong magnetic field, Coulomb scattering can be substantially modified because cyclotron motion (gyromotion) interacts with the Coulomb potential. Consequently, charged particles may follow complex, S-shaped, or non-monotonic trajectories rather than the simple hyperbolic paths associated with conventional unmagnetized Coulomb scattering. The proposed mechanism provides the basis for examining the possible role of magnetized Coulomb scattering in the formation of solar magnetic switchbacks.