Force-field approximation (FFA) of Parker’s solar modulation equation is a simplification widely used for practical purposes. The wide use of FFA is motivated by the fact that the modulation strength can be described, with reasonable accuracy, using a single variable parameter $\phi$, which is called the solar modulation potential. While FFA does not allow us to study the solar modulation process in detail, the one-parameter feature is useful, especially in the context of energy- and particle-integrating detectors, such as neutron monitors and cosmogenic isotopes, which allows for studies of solar modulation on timescales beyond the direct measurements.
New daily data on proton and helium fluxes measured by cosmic-ray experiment AMS-02 for the period from 2011 to 2019 open new opportunities in the verification of the FFA of the solar modulation equation on a daily basis and in a systematic comparison of the solar modulation deduced from different detectors (including energy-integrating ones). In this work, we reconstruct the solar modulation potential from daily AMS-02 data, compare it to daily solar modulation potential values reconstructed from NM data, and discuss the proper way to evaluate the solar modulation potential from different detectors to make them comparable.
