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Low‐Resource Technique for Measurement of H + and O + in the Terrestrial Magnetosphere
Author(s) -
Fernandes P. A.,
Funsten H. O.,
Dors E. E.,
Harper R. W.,
Larsen B. A.,
MacDonald E. A.,
Reisenfeld D. B.,
Skoug R. M.,
Steinberg J. T.,
Thomsen M. F.
Publication year - 2019
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2019ja027138
Subject(s) - magnetosphere , physics , spacecraft , detector , aperture (computer memory) , ion , spectrometer , foil method , nuclear physics , plasma , analytical chemistry (journal) , atomic physics , materials science , optics , chemistry , astronomy , quantum mechanics , acoustics , chromatography , composite material
Measurement of O + in the Earth's magnetosphere is important for monitoring and understanding the initiation and evolution of geomagnetic activity. During active times, O + can be the most abundant ion in the magnetosphere. Furthermore, because O + and H + damage exposed spacecraft materials through different processes, measurement and prediction of O + and H + fluxes is critical for understanding cumulative damage effects to these materials resulting from the ambient plasma environment of a spacecraft. We describe a simple technique for quantitative, in situ measurement of O + and H + fluxes using ultrathin foils. This technique is a low‐resource addition to a standard electrostatic energy‐per‐charge analyzer followed by an array of detectors. H + and O + abundances up to a few tens of keV can be determined by comparison of counts in detectors having no ultrathin foil at the detector aperture, in which both H + and O + are detected, and adjacent detectors having a foil over the aperture of the appropriate thickness to stop the transmission of O + but through which H + can transit. We describe three techniques for implementing this method enabling differentiation of O + and H + in an instrument package significantly simpler than traditional mass spectrometers.