1. Trapped radiation models
SPENVIS Final Presentation
14 December 1999
Trapped radiation models
D. Heynderickx
Belgisch Instituut voor Ruimte-Aëronomie
Ringlaan 3, B-1180 Brussel
BIRA/IASB

3. Earth’s Van Allen belts
Galactic cosmic rays
Solar energetic particles
Secondary (albedo) radiation
Radiation belts

4. Particle motion: gyration, bounce, drift
Charged particle trapping
Particle motion: gyration, bounce, drift
Guiding centre approximation: McIlwain’s (B,L) coordinates
Model description: J(E,B,L)

5. Trapped proton population

6. Trapped electron population

7. The South Atlantic Anomaly
Low altitude part of radiation belts
Tilt and shift of geomagnetic field: Fraser-Smith, Rev. Geophys., 25, 1, 1987
Interaction with neutral atmosphere

8. The South Atlantic Anomaly (SAA)

9. Trapped proton variability
Solar cycle
Seasonal
Secular variation of geomagnetic field
Impulsive

10. Directional proton flux >18 MeV at 500 km
Secular variation
AP-8 MIN
SAMPEX/PET
Directional proton flux >18 MeV at 500 km

11. Impulsive penetration

14. CRRESELE Equatorial L profiles
Parametrized in terms of Ap15: 15 day average of Ap

16. Available models De facto standard models: NASA AP-8 and AE-8
Advantages of the NASA models:
Widespread usage (heritage)
Full spatial coverage and energy range
Disadvantages of the NASA models:
Represent radiation environment of the 60’s and 70’s
Static models (but probably ok for long time averages)
Contamination by Starfish electrons
Other models:
CRRESPRO, CRRESELE
NOAAPRO
POLE
SAMPEX/PET

17. Replacement of AP-8 and AE-8
New models do not have sufficient spatial and/or temporal coverage and/or energy range
Incomplete energy range can lead to misleading effects estimations

18. Standardisation efforts
COSPAR Panel for Radiation Belt Environment Modeling (PRBEM)
NASA working group meeting:
Focus efforts on selected regions of space and energy ranges to expedite AP-8 and AE-8 replacement
POLE model for GEO
SAMPEX/PET+NOAAPRO for LEO protons
ONERA/LANL GPS modelling for MEO
RERMM study: use data from different satellites + Salammbô numerical simulation to produce ‘ad hoc’ models