1. 21 ECRS, Kosice, 12/09/2008 Trapped charge particles measurements in the radiation belt by PAMELA instrument Vladimir V. Mikhailov (MEPHI) for PAMELA collaboration

2. PAMELA experiment Satellite ResursDK №1: The launch 15/ 06/ 2006; Elliptical orbit : 350- 610km with inclination ~70 0 3 axis stabilization. Information about the satellite attitude is stored on-line every ~1-180sec Count rate of top PAMELA counter: low energy ~MeV protons rate. South Atlantic Anomaly (SAA) is clearly seen Pitch angle count rate in SAA. See Poster of V.Malakhov P2.08 for more details

3. Altitude 350 – 400km, L=1.10-1.15 Altitude 550 – 600km, L=1.10-1.15 Determination of SAA’s boundaries: For determination of SAA boundaries the protons count from geomagnetic coordinates L,B was plotted for different altitudes and rigidities. Protons R<500Mev Protons 0.5<R<1Gev Protons 1<R<1.5Gev Protons 1.5<R<2Gev Protons R>2.5Gev B,Gaus L -shell Altitude 350-400 km PAMELA can observe low edge of the inner radiation belt 0.17<B<0.21Gs, L shell 1.-1.7

4. Size of SAA for altitudes between 350-600km Altitudes changes from 350 to 600km Longitude Latitude B<0.21Gs, L-shell <1.2

5. Proton spectrum in SAA, polar and equatorial regions

6. Proton spectrum in SAA for different B values B>0.24Gs B=0.23Gs B=0.21Gs B=0.19Gs L<1.2

7. PAMELA and AP8min model AP8 model line was normalized at 0.1GeV to data point L=1.2 B=0.2Gs

8. Pitch-angle distribution in SAA 1/(m2*sr*sec*MeV) Data of August-September, 2006 Observed distribution of protons with E~200-250MeV Distribution corrected for angular efficiency of the instrument, (red line)

9. Proton spectrum in SAA for different pitch-angles Kinetic Energy,Gev 1/(m2*sr*sec*MeV) August-September, 2006

10. Pitch angle distribution in SAA for different energies 1/(m2*sr*sec*MeV) August-September, 2006 Pitch-angle, deg.

11. Solar modulation Proton spectra since August 2006 till September of 2007: effect of solar modulation is visible. Low energy proton intensity is increasing with time The difference of solar modulation parameter. Since 07.2006 till 02.2008. Data of Apatity neutron monitor are taken from http://jag.cami.jccbi.gov/Helio/helio.asp (provided by Eduard Vashenuk)http://jag.cami.jccbi.gov/Helio/helio.asp Galactic proton spectra

12. trapped protons: modulation or boundary effects? It looks the flux of trapped high energy protons is decreasing in period of observation since August 2006 till September 2007 It needs more study because conditions of observation vary month by month 0.2 0.5 Galactic proton spectra Trapped proton spectra

13. Trapped He and electrons electrons: He nuclei Observation at L 0.24Gs (equatorial subcut-off data) and B<0.21Gs (SAA data)

14. Conclusion 1) PAMELA observed geomagnetically trapped particles near lower edge of SAA 0.18<B<0.21Gs in wide energy range from ~100MeV 2) New data could be used to improve empirical and theoretical models of the inner radiation belt such as, AP-8, etc