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Midnight flash model of energetic neutral atom periodicities at Saturn
Author(s) -
Carbary J. F.,
Mitchell D. G.
Publication year - 2017
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2017ja024296
Subject(s) - saturn , midnight , noon , physics , energetic neutral atom , flash (photography) , astrophysics , astronomy , magnetosphere of saturn , enceladus , atmospheric sciences , ion , magnetosphere , magnetic field , planet , optics , magnetopause , quantum mechanics
The Ion Neutral Camera on the Cassini spacecraft made images of energetic H atoms (25–55 keV) over a 3 day span in 2017. The images were projected onto the equatorial plane of Saturn, and a keogram was made by interpolating the projections in local time at 9 R S (1 R S = 60268 km). The keogram intensities show strong periodicities near the 10.79 h period of Saturn's energetic particles and exhibit a slope commensurate with corotation at that period. These periodic fluxes intensify near midnight but are weaker near noon. A “midnight flash” model can explain this behavior in terms of a searchlight rotating at 10.79 h that intensifies in the midnight sector. The model can also describe similar activity in Saturn's kilometric radiation and magnetic fields, although the “flash” must be shifted to the dawn‐to‐noon sector.