Real-Time Monitoring of Solar Energetic Particles Using the Alpha Magnetic Spectrometer on the International Space Station

Abstract

The International Space Station (ISS) orbits at an average altitude of 400 km, in the Low Earth Orbit (LEO) and is regularly occupied by astronauts. The material of the Station, the residual atmosphere and the geomagnetic field offer a partial protection against the cosmic radiation to the crew and the equipment. The solar activity can cause sporadic bursts of particles with energies between ∼10 keV and several GeVs called Solar Energetic Particles (SEPs). SEP emissions can last for hours or even days and can represent an actual risk for ISS occupants and equipment. The Alpha Magnetic Spectrometer (AMS) was installed on the ISS in 2011 and is expected to take data until the decommissioning of the Station itself. The instrument detects cosmic rays continuously and can also be used to monitor SEPs in real-time. A detection algorithm developed for the monitoring measures temporary increases in the trigger rates of AMS, using McIlwain’s L-parameter to characterize different conditions of the data-taking environment. A real-time monitor for SEPs has been realized reading data from the AMS Monitoring Interface (AMI) database and processing them using the custom algorithm that was developed.