Authors: Collier, Michael R.; Hamilton, D. C.; Gloeckler, G.; Ho, G.; Bochsler, P.; Bodmer, R.; Sheldon, R.
Reference: Journal of Geophysical Research, 103, 7-14, 1998.
Measurements of the O-16 and O-18 distribution functions in the solar wind at low to average solar wind speeds from the MASS instrument on the Wind spacecraft are reported. The O-16/O-18 density ratio is 450 #&177; 130, a value consistent with terrestrial, solar photospheric, solar energetic particle, and galactic cosmic ray O-16/O-18 isotopic ratios. This study constitutes the first reported spacecraft measurement of the isotope O-18 in the core solar wind and may represent the best determination of the solar O-16/O-18 density ratio to date.