Jupiter Radiation Environment. Nicolas André. RPWI Kick-Off Meeting, Uppsala, Sweden , November 26-27 2009. Jupiter Radiation Environments. Radiation effects . Radiation environments. Total Ionizing Dose (TID) - Cumulative long- term ionizing damage
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
RPWI Kick-Off Meeting, Uppsala, Sweden, November 26-27 2009
FromInsoo Jun, JPL
FromHank Garrett, JPL
Salammbô “Family” of Radiation Models
Take advantage of all these pre-existing models by combining them together and then get the best specification we could obtain at the present time for any spacecraft which will fly in the Jovian magnetosphere
In practice: (e.g., electron model)
The model currently available at ESA allows to combine D&G83, plus GIRE plus Salammbô. The selection from one model to the other is done first according to L and then according to the energy.
=> JOP/JOE model provided by ONERA
On-goingcontractwithQinetiq (ONERA) to improve the model and implementit in SPENVIS
The end results of the models are used to constrain potential mission scenarios and estimate the total radiation dose.
It is therefore critical tohave a good and robust understanding of the radiation environment of Jupiter.
=> Radiation Working Group set up (Dec. 2010)
Recommandations only !
Courtesy of Arnaud Boutonnet, ESOC
The JGO willalwaysorbitbeyond ~12 Rj
Mission requirement: total radiation dose below 150 kradbehind 8 mm Al shielding
Jovian radiation belts (electron, protons) have been modelled empirically (D&G, GIRE) and physically (Salammbô) by various groups in the United States (JPL, SwRI) and in Europe (ONERA):
a) different approaches
b) different input parameters (e.g., magnetic field models)
c) different spatial coverage
d) different energy coverage
Courtesy of Sébastien Bourdarie, ONERA
The JGO willalwaysorbitbeyond ~12 Rj => use of the GIRE or D&G models
From Arno Wielders, ESTEC
From Karla Clark, JPL
Jun et al., 2005 (GIRE)
Khurana et al., Icarus, 2007
When in orbitaroundGanymede:
The JGO spacecraft (assumed ~POLAR) willencounterdifferentfieldlinestopology
and, hence, different radiation doses
Shieldingeffectfrom the moon not yetmodelled (itwilldecrease the dose)
Khurana et al., Icarus, 2007
Ganymede’s polar regions are brightened in response to being open to jovian plasma
Leading/trailinghemisphericasymmetriesatlower latitudes (closedfieldlines)
to the Jovian plasma
for ions and electrons:
=> Wewere on fieldlinesconnected
to bothGanymede and jupiter
by a factor up to 10 !
Williams et al., JGR, 1998
Disadvantages of combining all existingmodelstogether: discontinuities …
Re-analysis of all existing data, empricialfitsproposedundervariousassumptions
Far frombeing mature and totallyagreed, but couldbe the reference model (ESA)
in a few months (not before end of assessment phase …)
=> New Radiation model currently built by ONERAand reviewed by ESA and Radiation Working Group