A New Mechanism for Early‐Time Plasmaspheric Refilling: The Role of Charge Exchange Reactions in the Transport of Energy and Mass Throughout the Ring Current—Plasmasphere System. Issue 10 (11th October 2022)

• Record Type: Journal Article
• Authors: Liu, Jianghuai; Ilie, Raluca; Borovsky, Joseph E.; Liemohn, Michael W.
• Is Part Of: Journal of geophysical research. Volume 127:Issue 10(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-10-11
• Subjects: inner magnetospheric cold ions -- plasmasphere -- ring current -- hydrogen exosphere -- numerical modeling; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2022JA030619
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: Cold H + produced via charge exchange reactions between ring current ions and exospheric neutral hydrogen constitutes an additional source of cold plasma that further contributes to the plasmasphere and affects the plasma dynamics in the Earth's magnetosphere system; however, its production and associated effects on the plasmasphere dynamics have not been fully assessed and quantified. In this study, we perform numerical simulations mimicking an idealized three‐phase geomagnetic storm to investigate the role of heavy ion composition in the ring current (O + vs. N + ) and exospheric neutral hydrogen density in the production of cold H + via charge exchange reactions. It is found that ring current heavy ions produce more than 50% of the total cold H + via charge exchange reactions, and energetic N + is more efficient in producing cold H + via charge exchange reactions than O + . Furthermore, the density structure of the cold H + is highly dependent on the mass of the parent ion; that is, cold H + deriving from charge exchange reactions involving energetic O + with neutral hydrogen, populates the lower L‐shells, while cold H + deriving from charge exchange reactions involving energetic N + with neutral hydrogen populates the higher L‐shells. In addition, the density of cold H + produced via charge exchange reactions involving N + can be peak at values up to one order of magnitude larger than the local plasmaspheric density, suggesting that solely considering the supply of cold plasma from the ionosphere to the plasmasphere can lead to a significant underestimation of plasmasphere density. Key Points: Ring current heavy ions are responsible for the production of over 50% of the cold H + population following a geomagnetic storm The density of H + produced via charge exchange reactions can be as high as ∼10 times the local plasmaspheric density Cold H + production is limited by the abundance of heavy ions from the plasma sheet source; the exospheric structure does not play a role