Volume 358 - 36th International Cosmic Ray Conference (ICRC2019) - SH - Solar & Heliospheric
Features of the Cosmic Ray Anisotropy in the Minima for # 23 - 25 Solar Cycles
M. Siluszyk,* K. Iskra, W. Wozniak, R. Modzelewska, M. Alania
*corresponding author
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Pre-published on: 2019 August 22
Published on:
Abstract
We study the role of drift effect in the temporal changes of the anisotropy of galactic cosmic ray
(GCR) and the influence of the sector structure of the heliospheric magnetic field (HMF) on it.
We analyze the GCR anisotropy in the solar cycle 24 and solar minima: 23/24 with negative
polarity (A<0) for the period of 2007 - 2009 and 24/25 with positive polarity (A>0) in 2017 - 2018
using data of global network of Neutron Monitors (NMs). We use the harmonic analyses method
to calculate the radial A$_r$ and tangential A$_f$ components of the anisotropy of GCR for different
sectors (’+’ corresponds to the positive and ’-’ to the negative directions) of the HMF. We compare
the analysis of the GCR anisotropy using the median rigidity R$_m$ of NM response (e.g., Ahluwalia
et al. 2015) and the effective rigidity R$_{ef}$ characteristic for each NM proposed by Gil et al. (2017).
Then the radial A$_r$ and tangential A$_f$ components are used for characterizing the GCR modulation
in the heliosphere. We show that in the solar minimum 23/24 in 2007-2009 when A<0, the drift
effect is not visibly evident in the changes of the component, i.e. for this solar minimum drift
effect is ~4%
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