The heliospheric modulation of electrons and positrons over a complete solar cycle
Abstract
The solutions of a comprehensive three-dimensional drift model are compared to PAMELA and
AMS-02 spectra of electrons and positrons in order to describe and understand their different
modulation down to 1 MeV. This is based on newly constructed very local interstellar spectra.
The focus of the study is on a full solar cycle, the period from 2006 to 2017. Comparison of
observations and modeling provides insight into how the three major diffusion coefficients change
during a complete solar cycle, especially during a prolonged solar minimum and the period of the
polarity reversal of the magnetic field during solar maximum activity, and to what extent drift
effects evolve. In this context, the electron to positron ratio is computed from 1 MeV to 50 GeV,
explaining the PAMELA and AMS-02 observed ratio in detail. Predictions are made of what may
be observed during the next, imminent solar minimum