The geocoronal H α cascade component determined from geocoronal H β intensity measurements

Abstract

AbstractGeocoronal H α and H β intensity measurements using the Wisconsin H α Mapper Fabry‐Perot are used to determine the intensity of the H α cascade component. From basic atomic physics and the work of Meier (), we show that the total cascade in geocoronal H α emission is 0.52 ± 0.03 times the geocoronal H β intensity, I(H β), for solar Lyman series excitation of geocoronal hydrogen. The results are consistent with the H α cascade measurements of Mierkiewicz et al. (), which were determined directly from the analysis of H α line profile measurements, and significantly narrow the range of uncertainty in the cascade measurement. Accounting for cascade is essential in determining exospheric effective temperatures and dynamics from the shape of the geocoronal H α line.