Heavy Metal and Rock in Space: Cluster RAPID Observations of Fe and Si
Haaland, Stein; Daly, Patrick W.; Vilenius, Esa, 2021: Heavy Metal and Rock in Space: Cluster RAPID Observations of Fe and Si. In: Journal of Geophysical Research: Space Physics, Band 126, 3, DOI: 10.23689/fidgeo-4335.
Metallic and silicate ions carry essential information about the evolution of the Earth and near‐Earth small bodies. Despite this, there has so far been very little focus on ions with atomic masses higher than oxygen in the terrestrial magnetosphere. In this paper, we report on abundances and properties of energetic ions with masses corresponding to that of silicon (Si) and iron (Fe) in Earth's geospace. The results are based on a newly derived data product from the Research with Adaptive Particle Imaging Detectors on Cluster. We find traces of both Si and Fe in all of the regions covered by the spacecraft, with the highest occurrence rates and highest intensities in the inner magnetosphere. We also find that the Fe and Si abundances are modulated by solar activity. During solar maximum, the probability of observing Fe and Si in geospace increases significantly. On the other hand, we find little or no direct correlation between geomagnetic activity and Si and Fe abundance in the magnetosphere. Both Si and Fe in the Earth's magnetosphere are inferred to be primarily of solar wind origin.Key Points: A new data product from the Cluster mission is utilized to study heavy ions in geospace. Traceable amounts of silicon (Si) and iron (Fe) are found in all regions of space traversed by Cluster. The detected Si and Fe are most likely of solar wind origin.
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