Trajectory reconstruction in the Earth Magnetosphere using TS05 model and evaluation of geomagnetic cutoff in AMS-02 data
D Grandi ; B Bertucci45 ; MJ Boschini ... et. al. ; et al. ; - ASI Sponsor
Aug - 2015

Event Title : The 34th International Cosmic Ray Conference, 30 July- 6 August, 2015 The Hague, The Netherlands
Published in: Proceedings of Science PoS (ICRC2015)116
Publisher: PoS
type: Conference Proceedings

Our backtracing code (Geomagsphere), for Cosmic Rays trajectory reconstruction in the EarthMagnetosphere, has been developed using the latest models of Internal (IGRF-11) and External(Tsyganenko 1996 and 2005) field components. Backtracing technique was applied to AMS-02data to separate Primary Cosmic Rays Particles from Secondary particles. We tested the accuracyof Magnetic Field models (with and without the external fieldcomponent) comparing them withdata from satellite (GOES, 1998 and CLUSTER, 2004). In both periods TS05 reproduces themagnetic field strength with good accuracy. Moreover the specificity of the TS05 model, designedfor solar storms, was tested comparing it with data taken by CLUSTER during the last solar activeperiod (from 2011 to 2013). We found a relevant difference onthe fraction of AMS-02 cosmicrays identified as trapped and secondary particles, especially during solar flare periods (i.e. thoseoccurred in March and May 2012). Finally the backtracing of awide sample, more than 70 days,of AMS-02 proton data was used to get the real geomagnetic cutoff. We found an increasedcounting rate of primary particles at high latitudes with respect to the IGRF model. Besides webuilt a procedure to extract from data the rate of secondary particles.

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Notes : This work is supported by Agenzia Spaziale Italiana under contracts ASI-INFN I/002/13/0,Progetto AMS - “Missione scientifica ed analisi dati” and ASI-INFN I/037/14/0 - “Realizzazioneattività tecniche e scientifiche presso l’ASDC”