| Marco Casolino iRIKEN - Advanced Science Institute and INFN - Rome Tor Vergataj |
| Energy spectrum of proton and helium measured by PAMELA and
acceleration of cosmic rays in the galaxy |
| We will discuss the measurements of PAMELA Proton and Helium nuclei in
the rigidity range 1 GV - 1.2 TV. PAMELA is a satellite-borne magnet spectrometer detector orbiting the Earth on board the Russian Resurs-DK1 satellite since 2006. It is devoted to the high precision measurements of cosmic ray particle and antiparticles of galactic, solar and terrestrial origin. The data show that Proton and Helium nuclei have different spectral indexes, suggesting that the two particles undergo different acceleration mechanisms or are accelerated at different sites. Furthermore both spectra show a deviation from the power law around 230GV, hinting at an additional source which becomes detectable above there rigidities. The data will be discussed in light of the measurements coming from balloons, extendend air shower and gamma ray telescopes. Also recent measurements of electrons, positrons and antiprotons will be discussed. |