Dr. Cristina Consolandi on "Time Evolution of Proton and Helium Fluxes with AMS-02 "

Thursday Nov 17, 2016, 3:30 PM → 4:30 PM Pacific/Honolulu

112 (Watanabe Hall)

The Alpha Magnetic Spectrometer (AMS-02), on the International Space Station (ISS) since May 2011, has just celebrated its fifth year of data acquisition. The number of particles collected during this period is the largest ever measured in space by a single experiment which provides the most precise galactic cosmic ray measurement to date. During this talk the detector characteristics will be review and the precise measurement of the proton and helium fluxes from 1 GV up to a few TV will be presented. The results show that both proton and helium fluxes are smooth and exhibit no sharp structures with rigidity. At high energy both spectra cannot be described by a single power low. Detailed time variation studies show that the high rigidity range remains stable versus time, while the low-energy range exhibits interesting time variation phenomena and sub-structures related to the solar activity. During this review, particular attention will be given to the measurement of these fluxes below 100 GV, where the long term solar modulation effect is evident. These data were collected during the reversal of the Sun's magnetic field polarity (from negative A<0 to positive A>0) in solar cycle 24 from its ascending phase trough maximum versus minimum. In addition, the detailed flux behavior shows sub-structures immersed in the long term solar modulation which are related to the strongest solar events, i.e. coronal mass ejections (CME) and Forbush decreases (FD). The spectra of solar energetic particles (SEP) accelerated by the Sun, for a few events occurred during this period will be presented as well.