Post on 02-Jan-2016
transcript
SPECTRAL SHAPE OF
SOLAR PARTICLE EVENTS AT ENERGIES
ABOVE
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
Outline
• LISA-PF• GCR projections and SEP occurrence in
2015• SEP differential flux trend above 100
MeV/n• Conclusions
LISA-PF TEST MASSES AND RADIATION MONITORS
2 silicon wafersof 1.4 x 1.05 cm2 areaplaced 2 cm apart. Courtesy by A. Lobo
SUNSPOT PROJECTIONS IN 2015
Predicted Sunspotsin 2015: 595 and 95 percentile levels: 33 and 84
Solar modulation parameter expectedvariation: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
SEP EVENTS DURING LISA-PF
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 (NSEPS) in terms of both event fluence and peak fluxes on the basis of expected yearly SS (NSS):
NSEPS=0.0694 NSS
SEP fluence distribution is assumed to follow a power-law trend with an exponential decrease for large fluences.
SEP PROJECTIONS IN 2015
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 106 protons/cm2
> 30 MeV
SEPS OF DIFFERENT INTENSITIES 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
GCR IN 2015 AND SEP EVENTS SEP Event February 23rd 1956
SEP Event December 13th andDecember 14th2006
Adriani et al., 2011
Vashenyuk et al., 2007
SEP FLUX INTERPOLATION FUNCTIONS
(1) F(E)= A e-E/b Particles/[m2 sr s GeV(/n)]
(2) F(E)= A E- g Particles/[m2 sr s GeV(/n)]
(3) F(E)= A e-E/b E- g Particles/[m2 sr s GeV(/n)]
Ellison and Ramaty, 1985
CONCLUSIONS
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.