Confronting the AP9/AE9 Radiation Belt Models with Spacecraft Data and Other Models

D.HeynderickxDH Consultancy, Leuven, BelgiumP.R. TruscottKallisto Consultancy, Farnborough, UK

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ESA Contract No. 4000108483/13/NL/AK

ESA Technical OfficersH. Evans, E.J. Daly

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Context• Concern in European space industry about higher fluxes (and

thus doses) predicted by AP9/AE9• Analysis of differences with other models• Implementation in SPENVIS• User education• Recommendations for ECSS space environment standard• Feedback to the IRENE team of issues encountered during the

analysis

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Comparison methods• Intercomparison of models• Run different models on a spacecraft trajectory set of points, for

representative orbits (LEO, MEO, GTO, GEO)• Comparison of trajectory fluences• Comparison of fluences used in radiation effects models (TID,

NIEL, solar cell degradation)• Comparisons of model fluxes to spacecraft data• Run models on the trajectory data in the various datasets, for the

energy bins of the instruments.• Compare time series and fluence spectra.• Try to account for anisotropy effects in LEO. Eu

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Test scenarios: generic trajectories

• Geostationary at longitudes 75°, 180° and 285°• Comparison with AP/AE-8, IGE

• GTO: inc 5°, perigee 300 km, apogee 36,000 km• Comparison with AP/AE-8, CRRESELE, CRRESPRO

• MEO (Galileo GNSS): circular, altitude 23,222 km, inc 56°• Comparison with AP/AE-8, CRRESELE, CRRESPRO

• MEO (GPS): altitude 20,200 km• Comparison with AP/AE-8, CRRESPRO, CRRESELE, MEO-V1/2

• Sun-synchronous: altitude 800 km (inc 98.6°)• Comparison with AP/AE-8

• Large Observatory for X-ray Timing (LOFT): circular, altitude 600 km• Comparison with AP/AE-8

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SSO Proton spectra

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SSO Electron spectra

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SSO SHIELDOSE-2: protons

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SSO SHIELDOSE-2: e-, Bremsstrahlung

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GEO electron flux

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MEO (GPS) electron flux

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Test scenarios: datasets• Procedure:• Convert spacecraft ephemeris to SPENVIS and IRENE trajectory

file format (identical for GDZ except for shift in MJD)• Run models using the instrument energy channels• Compare orbit evolution plus trajectory fluence spectra

• Datasets:• CRRES/MEA: 110 keV – 1.6 MeV electrons • AZUR/EI-88: 1.5–104 MeV protons• Giove-B/SREM: calibrated electron channels• Integral/SREM: calibrated electron channels• SAMPEX/PET: 19–500 MeV protons

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AZUR data selection

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AZUR data comparison

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AZUR mission comparison

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CRRES/MEA data selection

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CRRES/MEA: quiet conditions

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CRRES/MEA: active conditions

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CRRES/MEA: active spectra

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Giove-B/SREM: active spectra

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Conclusions (1)• More analysis is needed to compare the models to longer time

averages of the datasets.• GEO environment• AE-8 and AE-9 Mean are comparable, AE-9 extends the energy

range (needs evaluation).• IGE2006 (ECSS model) is (much) lower.• High energy flux predictions need further evaluation in view of

updates of ECSS• Are longitudinal effects important?

• LEO• AP-9 overestimates the extent of the SAA region.• AP-9 overestimates below ~70 MeV and underestimates above.• AE-9 is consistently higher than AE-8 except for >1.5 MeV

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Conclusions (2)• MEO• MEOV2 mean is lower than AE-9 mean, MEOV2 upper is in good

agreement with AE-9 90%.• High energy component needs further evaluation. Until then, AE-

8/MAX can be used in this region.• Pending long term model to data comparisons, the ECSS

recommendation (MEOV2) can be maintained.

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Recommendations• A more in-depth analysis is needed to evaluate the models

(IRENE and other) with longer time averages of spacecraft data.• Construct (omni-)directional flux maps from AZUR/EI-88 and

SAMPEX/PET proton data• Analyse PROBA-V/EPT data• Analysis of the high energy electron spectrum

• Ingest AZUR/EI-88, SAMPEX/PET and RBSP/REPT/MAGEIS data into the IRENE models.

• Provide more detailed information on the construction of the IRENE models.

• Review the usage of the confidence level and Monte Carlo versions of the models.

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