Photodetachment and Test-Particle Simulation Constraints on Negative Ions in Solar System Plasmas

Abstract

Negative ions have been detected in abundance in recent years by spacecraft across the solar system. These detections were, however, made by instruments not designed for this purpose and, as such, significant uncertainties remain regarding the prevalence of these unexpected plasma components. In this article, the phenomenon of photodetachment is examined and experimentally and theoretically derived cross-sections are used to calculate photodetachment rates for a range of atomic and molecular negative ions subjected to the solar photon spectrum. These rates are applied to negative ions outflowing from Europa, Enceladus, Titan, Dione and Rhea and their trajectories are traced to constrain source production rates and the extent to which negative ions are able to pervade the surrounding space environments. Predictions are also made for further negative ion populations in the outer solar system with Triton used as an illustrative example. This study demonstrates how, at increased heliocentric distances, negative ions can form stable ambient plasma populations and can be exploited by future missions to the outer solar system.

arXiv commentPlanetary Science Journal Article, accepted 05 April 2021. Preprint contains 21 pages, 8 figures, 1 table

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Cited by in corpus (4)

• Drift Orbit Bifurcations and Cross-field Transport in the Outer Radiation Belt: Global MHD and Integrated Test-Particle Simulations
• Simulating secondary electron and ion emission from the Cassini spacecraft in Saturn's ionosphere
• Production and Loss Processes of Hydrogen Energetic Neutral Atoms in the Heliosphere from 5 eV to 500 keV
• Highly correlated electronic bounding and spin effect: confirmation of an autodetaching state of O${}^{-}$