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

Geocoronal H alpha and H beta intensity measurements using the Wisconsin H alpha Mapper Fabry-Perot are used to determine the intensity of the H alpha cascade component. From basic atomic physics and the work of Meier (1995), we show that the total cascade in geocoronal H alpha emission is 0.52 +/- 0.03 times the geocoronal H beta intensity, /(H beta), for solar Lyman series excitation of geocoronal hydrogen. The results are consistent with the H alpha cascade measurements of Mierkiewicz et al. (2012), which were determined directly from the analysis of H alpha 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 alpha line.