GLE and the NON-GLE Solar Events Observed by AMS-02 in Solar Cycle 24

Abstract:

The Alpha Magnetic Spectrometer (AMS-02) is a high energy particle detector
installed on the International Space Station (ISS) on May 2011 to study origin
and nature of cosmic rays in the energy range from hundreds of MeV to a few TeV.
In the first 3 years of operation, AMS-02 measured the highest part of the Solar
Energetic Particle (SEP) spectra produced during M-and X-class flares and fast
Coronal Mass Ejection. AMS-02 is able to perform precise measurements in a short
period of time which is typical of these transient phenomena and to collected enough
statistics to fully measure fine structures and time evolution of the spectrum.
So far in Solar Cycle 24, one official Ground Level Enhancement (GLE) was observed
on May 17, 2012 by Neutron Monitors (NM) while another possible GLE on January 6, 2014
was detected by South Pole NM. Observations by GOES-13, in the high energy proton channels,
suggest that there were only 5 SEP events with energies above 500 MeV in this Cycle 24.
AMS-02 observations, instead, indicate that since May 2011 there were more than 5 solar events with
energies above 500 MeV at Earth. AMS-02 observations, with unprecedented resolution,
large acceptance and high statistics, can therefore help the heliophysics community to better
understand the true behavior of SEPs at high energies and to constrain models of SEP production.
The SEP fluxes of GLE and NON-GLE events observed by AMS-02 will be presented.