AMS-02 Monthly proton flux: Solar modulation effect and short timescale phenomena

Abstract

The Alpha Magnetic Spectrometer (AMS-02) is a high-energy particle detector designed to per- form fundamental physics research in space. It was installed on the International Space Station (ISS) on May 19th, 2011 where it will operate for the next decade. During the first 30 months of operation, AMS-02 collected 41 billion events of cosmic rays between 1 GV and 1.8 TV. In this work, the detailed time variation of the proton flux below 10 GV with a monthly time-based inte- gration was analyzed. While at high energy the spectra remains stable versus time, the low-energy range exhibits a decreasing general trend, strongly reflecting the increase of the solar activity that recently reached its maximum. In addition to the overall modulation effect, the monthly AMS-02 proton flux shows periodic variations related to strong solar events i.e. Coronal Mass Ejections and Forbush decreases.