Experimental Investigation of the Delay Time in Galactic Cosmic Ray Flux in Different Epochs of Solar Magnetic Cycles: 1959 – 2014

Iskra, K.; Siłuszyk, Marek; Alania, M. V.; Wozniak, Witold

doi:10.1007/s11207-019-1509-4

Cited by 19 publications

(10 citation statements)

References 31 publications

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“…Nonetheless, there are some discrepancies with the reported val- ues if one account for even/odd cycle dependence of the lag. Our estimation of the time lag lies in solar cycle 24, but it appears longer than that reported in previous even-numbered solar cycles, though it is comparable to the lag observed in odd-numbered solar cycles (Aslam & Badruddin 2015;Singh 2008;Iskra et al 2019). In this respect, cycle 24 is unusual when compared to previous cycles.…”

Section: Lags and Loopssupporting

confidence: 54%

Numerical modeling of cosmic rays in the heliosphere: Analysis of proton data from AMS-02 and PAMELA

Fiandrini,

Tomassetti,

Bertucci

et al. 2020

Preprint

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Galactic cosmic rays (CRs) inside the heliosphere are affected by solar modulation. To investigate this phenomenon and its underlying physical mechanisms, we have performed a data-driven analysis of the temporal dependence of the CR proton flux over the solar cycle. We have modeled the solar modulation effect by means of stochastic simulations of cosmic particles in the heliospheric plasma. We have constrained our model using the recent time-resolved measurements of CR proton fluxes reported by AMS-02 and PAMELA experiments, on monthly basis, from mid-2006 to mid-2017. With a global statistical analysis, we have determined the key model parameters that rules the CR transport, its dependence on the particle rigidity, and its evolution over the solar cycle. Our data sample comprises epochs of solar minimum, solar maximum, as well as epochs with magnetic reversal and opposite polarities. Along with the evolution of the CR transport parameters, we study their relationship with solar activity proxies and interplanetary parameters. We find that the rigidity dependence of the parallel mean free path of CR diffusion shows a remarkable time dependence, indicating a long-term variability in the interplanetary turbulence that interchanges across different regimes over the solar cycle. The evolution of CR diffusion parameters show a delayed correlation with the sunspot number, reflecting the dynamics of the heliospheric plasma, and different dependencies for opposite states of magnetic polarity, reflecting the influence of charge-sign dependent drift in the CR modulation.

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Section: Lags and Loopssupporting

confidence: 54%

Numerical modeling of cosmic rays in the heliosphere: Analysis of proton data from AMS-02 and PAMELA

Fiandrini,

Tomassetti,

Bertucci

et al. 2020

Preprint

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“…Siluszyk, Wawrzynczak, and Alania, 2011;Siluszyk, Iskra, and Alania, 2015). On the one hand, it allows one to understand the behavior of GCRs particles transport in the heliosphere Jokipii, 1983, 1998;Potgieter and Moraal, 1985;Burger and Potgieter, 1989;Potgieter, 1995;Alania et al, 2001;Siluszyk et al, 2018;Siluszyk, Iskra, and Alania, 2014;Iskra, Siluszyk, and Alania, 2015;Alania, Iskra, and Siluszyk, 2010;Iskra et al, 2019). On the other hand, the clearly revealed drift effect in GCR anisotropy allows to estimate the various parameters characterizing the SW and the diffusion of GCRs (Alania, Bochorishvili, and Iskra, 2003).…”

Section: Introductionmentioning

confidence: 99%

Features of the Galactic Cosmic Ray Anisotropy in Solar Cycle 24 and Solar Minima 23/24 and 24/25

Modzelewska

Iskra

Wozniak³

et al. 2019

Sol Phys

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We study the role of the drift effect in the temporal changes of the anisotropy of galactic cosmic rays (GCRs) and the influence of the sector structure of the heliospheric magnetic field on it. We analyze the GCR anisotropy in Solar Cycle 24 and solar minimum 23/24 with negative polarity (qA < 0) for the period of 2007-2009 and near minimum 24/25 with positive polarity (qA > 0) in 2017-2018 using data of the global network of Neutron Monitors. We use the harmonic analysis method to calculate the radial and tangential components of the anisotropy of GCRs for different sectors ('+' corresponds to the positive and '−' to the negative directions) of the heliospheric magnetic field. We compare the analysis of GCR anisotropy using different evaluations of the mean GCRs rigidity related to Neutron Monitor observations. Then the radial and tangential components are used for characterizing the GCR modulation in the heliosphere. We show that in the solar minimum 23/24 in 2007-2009 when qA < 0, the drift effect is not visibly evident in the changes of the radial component, i.e. the drift effect is found to produce ≈ 4% change in the radial component of the GCR anisotropy for 2007-2009. Hence the diffusion dominated model of GCR transport is more acceptable in 2007-2009. In turn, near the solar minimum 24/25 in 2017-2018 when qA > 0, the drift effect is evidently visible and produces ≈40% change in the radial component of the GCR anisotropy for 2017-2018. So in the period of 2017-2018 a diffusion model with noticeably manifested drift is acceptable. The results of this work are in good agreement with the drift theory of GCR modulation, according to which, during negative (positive) polarity cycles, a drift stream of GCRs is directed toward (away from) the Sun, thus giving rise to a 22-year cycle variation of the radial GCR anisotropy.

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“…For a given station d, the modulation lag ∆T is determined as the parameter that maximizes the correlation between the modulation φ(t) at epoch t and the smoothed SSNŜ(t − ∆T). A similar approach was adopted in other works [3,37,38]. To quantify the correlation level, we used the Spearman's rank correlation criterion.…”

Section: Gcr Particles Where ∆E − |Z |mentioning

confidence: 99%

New insights from cross-correlation studies between Solar activity and Cosmic-ray fluxes

Tomassetti¹,

Bertucci²,

Fiandrini³

2021

Proceedings of 37th International Cosmic Ray Conference — PoS(ICRC2021)

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The observed variability of the cosmic-ray intensity in the interplanetary space is driven by the evolution of the Sun's magnetic activity over its 11-year quasiperiodical cycle. Investigating the relationship between solar activity indices and cosmic-ray intensity measurements is then essential for understanding the fundamental processes of particle transport in the heliosphere. Here we have performed a global characterization the solar modulation of cosmic rays over the solar activity cycle and for different energies of the cosmic particles. We present our cross-correlation studies using data from space experiments, neutron monitors and solar observatories collected over several solar cycles.

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Experimental Investigation of the Delay Time in Galactic Cosmic Ray Flux in Different Epochs of Solar Magnetic Cycles: 1959 – 2014

Cited by 19 publications

References 31 publications

Numerical modeling of cosmic rays in the heliosphere: Analysis of proton data from AMS-02 and PAMELA

Numerical modeling of cosmic rays in the heliosphere: Analysis of proton data from AMS-02 and PAMELA

Features of the Galactic Cosmic Ray Anisotropy in Solar Cycle 24 and Solar Minima 23/24 and 24/25

New insights from cross-correlation studies between Solar activity and Cosmic-ray fluxes

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