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Title: Galileo interim radiation electron model : update—2012
Authors: Garrett, H. B.
Kokorowski, M.
Jun, I.
Evans, R. W.
Keywords: Jupiter Radiation Belts
Galileo spacecraft Energetic Particle Detector (EPD)
Galileo Spacecraft
High Energy Electrons,
Issue Date: Mar-2012
Publisher: Pasadena, CA : Jet Propulsion Laboratory, National Aeronautics and Space Administration, 2012.
Series/Report no.: JPL Publication
Abstract: Measurements of the high-energy, omnidirectional electron environment, and magnetic field by the Galileo spacecraft Energetic Particle Detector (EPD) and Magnetometer (MAG) were used to revise the original Divine and GIRE models of Jupiter’s trapped electron radiation in the jovian equatorial plane. 10-minute averages of the EPD data were averaged to provide an omni-directional differential flux spectrum at 0.238, 0.416, 0.706, 1.5, 2.0, 11.0, and 31 MeV (the latter based on estimates by Pioneer 10 and 11) in the jovian equatorial plane as a function of radial distance. This model has been combined with the original Divine model and recent synchrotron observations of jovian high energy electrons inside L = 4 to yield estimates of the radiation environment from ~1 to ~50 Jupiter radii (1 jovian radius = 71,400 km). The revised model, referred to here as the Galileo Interim Radiation Electron model-Version 2 (or GIRE2), is intended to address several concerns with the original Divine/GIRE model. In particular, there were noticeable discontinuities at the boundaries between the GIRE and the Divine models. Also, the GIRE model did not extend out past L=~16 and depended on the original Divine model for pitch angle distributions. The new GIRE2 model consists of an inner trapped omnidirectional model between L = 7.2 and 22.5 that has been modified to smoothly join onto the original Divine model between L = 7.2 and 10.5 and onto a GIRE2 plasma sheet model between L = 17 and 25. The latter component is a function of jovian radius and height above the plasma sheet as given by the Khurana magnetic field model. The model, the steps leading to its creation, and relevant issues and concerns are discussed in detail in the report. The GIRE2 model, like its predecessor GIRE, represents a step forward in the study of the jovian radiation environment and is a useful and valuable tool for estimating that environment for future missions to Jupiter.
Appears in Collections:JPL TRS 1992+

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