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Thermal iron ions in high speed solar wind streams: Detection by the IMP 7/8 energetic particle experiments
Author(s) -
Mitchell D. G.,
Roelof E. C.
Publication year - 1980
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl007i009p00661
Subject(s) - solar wind , ion , streams , physics , environmental science , plasma , nuclear physics , computer network , computer science , quantum mechanics
The first measurements of the abundance of iron ions in high speed (> 600 km s −1 ) solar wind streams have been made with the NOAA/JHU Energetic Particles Experiments (EPE) on IMP 7/8. The identification of iron ions is quantitatively established using 4 years of observations and heavy ion accelerator calibrations of detectors similar to those flown on the spacecraft. Preliminary estimates of the Fe/H ratio are within a factor of 2 of the adopted coronal abundance (5 × 10 −5 ), and there is some evidence that Fe/H may remain approximately constant within a given stream. In the peaks of fast streams (700 < V < 800 km s −1 ), about 50 iron ion counts are obtained every 20 s, offering the possibility of studying the Fe/H ratio with ∼ 1 m time resolution in high speed streams throughout the decline of Solar Cycle 20 and the rise of Solar Cycle 21.