Galactic cosmic-ray flux short-term variations and associated interplanetary structures with LISA Pathfinder

摘要

The European Space Agency LISA Pathfinder (LPF) mission orbited around the Sun-Earth first Lagrangian point L1 between January 2016 and July 2017. A particle detector aboard LPF allowed for galactic cosmic-ray (GCR) integral flux measurements above 70 MeV n~(-1) between 2016 February 18 and 2017 July 3 during the descending phase of the present solar cycle N. 24, which is characterized by a positive polarity period. The statistical uncertainty on hourly-averaged GCR countings was of 1%. The characteristics of recurrent and non-recurrent GCR flux short-term variations observed with LPF are reported here. In particular, it is focused on GCR flux variation profiles and their association with the passage of large-scale interplanetary structures. Forbush decrease observations and geomagnetic storm occurrence during LPF are also briefly discussed.