1. Florian Nichitiu, James R. Drumond, Jiansheng Zou, Robert Deschamault(*) Department of Physics, University of Toronto, Canada (*) COM DEV, Cambridge, Ontario, Canada. Florian Nichitiu June 2003, CAP South Atlantic Anomaly seen by MOPITT

2. Radiation effect on spacecraft systems and instruments Spacecraft anomalies: from -------- easily recovered to -------- total mission failure origin: -- engineering (operation fault, mechanism failure and ageing) -- space weather which simulate engineering faults— BUT not only Based upon the effect upon the s/c : Surface charging | Photonics noise Deep dielectric charging | Total dose effects Single Event Upset (SEU) | Material degradation Solar radio frequency interference | Spacecraft drag

3. Electrons AE-8Protons AP-8 Radiation Belt Models and South Atlantic Anomaly at 500Km altitude

4. Mopitt instrument Two piezoelectric accelerometers Cooler Compressor (vibrations for x,y,z) Cooler Displacer (vibrations for x,y,z) Multi-component force measurements Kistler: K-Shear accelerometer. Sensing element: quartz crystal

5. Mopitt Accelerometer anomalies

6. Mopitt Accelerometer Anomalies Daily rate = 1.06 ev/day SAA events = 54 % Poles ( +/- 70 ) = 19.4 %; North/South asymmetry=0.43

7. Mopitt Accelerometer Anomalies in South Atlantic Anomaly region Total time: 993 days; Total Nr ev over SAA=567 ( 54%) SAA rate= 0.57 ev/day Mopitt spend 6.25% of time over SAA  SAA rate=9.14 ev/day

8. SAA seen by Mopitt ------------ 

9. Solar Protons Events Detected by Mopitt accelerometer

10. Solar Proton Events Max p Flux pfu @ > 10 MeV 100 MeV Y1 Jul 14/15: 2000 24000 410 Y2 Nov 09: 2000 14800 347 N1 Sept 25: 2001 12900 31 Y3 Nov 06: 2001 31700 253 N2 Nov 24: 2001 18900 4 -Solar Proton Events ( from ftp://ftp.ngdc.noaa.gov/, ftp://ftp.ngdc.noaa.gov/ http://www.sel.noaa.gov/weekly/) Mopitt Accelerometer detect SPE at 6 Nov (during the second peak of proton flux)

11. SPE detected by Mopitt. Energy dependence

12. Mopitt Accelerometer Anomalies during intense SPE - are caused by high energy charged particles precipitating via ‘pole horns’. - more events during the Day

13. Double Solar Maximum

14. During High Solar Activity period ( II sub-max) the relative contribution of trapped particles in SAA decrease from 54% to 42% as a consequence of direct injection of more high energy particles

15. Correlation with Solar activity Mopitt Accelerometer anomalies are correlated with Solar Activity as shown by Solar Radio Flux : index F10.7 27 days average and smooth 27-average

16. Summary and conclusions Analysis of Mopitt accelerometer anomalies anomalies are located in the SAA and polar regions  anomalies are caused by the radiation environment (energetic particles). detection of SPE  the energetic particles are mainly high energy protons (30-50 MeV). Piezoelectric (SiO2) accelerometer  a possible new effect: piezoelectricity induced by corpuscular radiation. decrease of relative SAA contribution during High Solar Activity (second max)  injection of more high energy particles (via poles) during Solar Activity second sub-max ( Solar Cycle 23). direct correlation with Solar Activity as expressed by Solar Radio Flux (F107)  the Solar Radio Flux at 10.7 cm is a more complex proxy for Solar Activity.