1. Catia Grimani University of Urbino – INFN Florence Italy In collaboration with: M. Fabi, N. Finetti, M. Laurenza, M. Storini ECRS 2012 Moskow July 5th 2012 100 MeV/n

2. Outline LISA-PF GCR projections and SEP occurrence in 2015 SEP differential flux trend above 100 MeV/n Conclusions

4. LISA-PF inertial sensor and test mass V AC T1 V AC T2 VMVM C sen s1 C sen s2 V AC 100 kHz L L CpCp CpCp

5. 2 silicon wafers of 1.4 x 1.05 cm 2 area placed 2 cm apart. Courtesy by A. Lobo

6. Predicted Sunspots in 2015: 59 5 and 95 percentile levels: 33 and 84 Solar modulation parameter expected variation: 350 MV/c - 800 MV/c Usoskin et al.,2005, 2011 LISA-PF data taking http://solarscience.msfc.nasa.gov/predict.shtml CG et al., CQG, 2012

7. GC et al., CQG, 2012 and references therein  MV/c – 800 MV/c

8. We consider here SEP events associated with a peak flux equal or larger than the minimum GCR background expected in 2015. Nymmik’s model (Nymmik, 1999 a,b) allows us to predict SEP occurrence (N SEPS ) in terms of both event fluence and peak fluxes on the basis of expected yearly SS (N SS ): N SEPS =0.0694 N SS SEP fluence distribution is assumed to follow a power-law trend with an exponential decrease for large fluences.

9. The number of expected SEP events at the time of LISA-PF is: 1.1 min – 2.0 avg – 2.9 max with fluences above 10 6 protons/cm 2 > 30 MeV

10.  February 23rd 1956: N24W74  May 7th 1978: N23W72  September 29th 1989: S27W90  July 14th 2000: N22W07  April 15th 2001: S20W85  January 20th 2005: N14W61  December 13th and 14th 2006: S06W23 and S06W46

11. SEP Event February 23rd 1956 SEP Event December 13th and December 14th 2006 Adriani et al., 2011 Vashenyuk et al., 2007

12. (1) F(E)= A e -E/b Particles/[m 2 sr s GeV(/n)] (2) F(E)= A E -  Particles/[m 2 sr s GeV(/n)] (3) F(E)= A e -E/b E -  Particles/[m 2 sr s GeV(/n)] Ellison and Ramaty, 1985

16. SEP energy differential flux interpolation during the whole evolution of various intensity events above 100 MeV/n indicates (on average) that: the initial phase of SEP events is sometimes better represented by an exponential trend, however, in general, a power-law modulated by an exponential or power-laws and/or broken power-laws basically represent all phases of the events.