2003/07/31 by J. G. Luhmann
Physics and Astronomy · #Solar and Space Plasma Dynamics #Astro and Planetary Science #Ionosphere and magnetosphere dynamics
paper · pdf · doi:10.1086/375770
Theoretical analyses of the global heliospheric pickup ion population generally involve the solution of forms of the Boltzmann or transport equation. Like their cosmic-ray counterparts, these approaches often presume a simplified geometry for the interplanetary magnetic field and that diffusive processes dominate the already picked up particles' behavior. At the opposite extreme lies the test particle picture of pickup ions, wherein their motion is tracked from the birth of the ions through their outward travel in the Parker spiral magnetic field. This approach has the advantage that it can include details of the source distribution, the initial pickup by the solar wind convection electric field at the site of ion production, and the combined effects of the radially evolving electric and magnetic fields experienced by the ions. Here test particles representing O+ pickup ions are used to examine the influences of the source characteristics, including the heliocentric radius of their birth and the velocities of their parent neutrals. The consequences for ion populations from interstellar, interplanetary dust, and Jovian sources are considered. The results suggest some potentially observable features of general pickup ion distributions that could aid in the interpretation of their different sources.