Numerical modeling of cosmic-ray transport in the heliosphere and interpretation of the proton-to-helium ratio in Solar Cycle 24

Tomassetti, Nicola; Barão, F.; Bertucci, B.; Fiandrini, E.; Orcinha, M.

doi:10.1016/j.asr.2019.06.025

Cited by 16 publications

(10 citation statements)

References 53 publications

(76 reference statements)

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“…( 2019b ) addressed with numerical modeling the proton to Helium ratio observed by AMS–02 during the solar maximum of solar cycle 24, with similar studies done by Tomassetti ( 2017 ) and Tomassetti et al. ( 2019 ). Ngobeni et al.…”

Section: Advances In Global Models Of Solar Modulationmentioning

confidence: 60%

Galactic Cosmic Rays Throughout the Heliosphere and in the Very Local Interstellar Medium

et al. 2022

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We review recent observations and modeling developments on the subject of galactic cosmic rays through the heliosphere and in the Very Local Interstellar Medium, emphasizing knowledge that has accumulated over the past decade. We begin by highlighting key measurements of cosmic-ray spectra by Voyager, PAMELA, and AMS and discuss advances in global models of solar modulation. Next, we survey recent works related to large-scale, long-term spatial and temporal variations of cosmic rays in different regimes of the solar wind. Then we highlight new discoveries from beyond the heliopause and link these to the short-term evolution of transients caused by solar activity. Lastly, we visit new results that yield interesting insights from a broader astrophysical perspective.

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Section: Advances In Global Models Of Solar Modulationmentioning

confidence: 60%

Galactic Cosmic Rays Throughout the Heliosphere and in the Very Local Interstellar Medium

et al. 2022

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“…Nonetheless, we opted for fully numerical calculations that incorporates the essential physics of interstellar CR transport. Such an approach allows for a robust estimation of the LIS model uncertainties, that are considerable in the GeV energy region where no direct data are available [39,40]. The relevant LIS's for this work are the most abundant species such as CR proton (∼ 90 %) and helium nuclei (∼ 9 %).…”

Section: A Modeling the Lis Fluxesmentioning

confidence: 99%

Temporal evolution and rigidity dependence of the solar modulation lag of Galactic cosmic rays

Tomassetti¹,

Bertucci²,

Fiandrini³

2022

Preprint

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When traveling in the heliosphere, Galactic cosmic rays (CRs) are subjected to the solar modulation effect, a quasi-periodical change of their intensity caused by the 11-year cycle of solar activity.Here we investigate the association of solar activity and cosmic radiation over five solar cycles, from 1965 to 2020, using a collection of multichannel data from neutron monitors, space missions, and solar observatories. In particular, we focus on the time lag between the monthly sunspot number and the CR flux variations. We show that the modulation lag is subjected to a 22-year periodical variation, ranging from about 2 to 14 months and following the polarity cycle of the Sun's magnetic field. We also show that the lag is remarkably decreasing with increasing energy of the CR particles. These results reflect the interplay of basic physics phenomena that cause the CR modulation effect: the drift motion of charged particles in the interplanetary magnetic field, the latitudinal dependence of the solar wind, the energy dependence of their residence time in the heliosphere. Based on this interpretation, we end up with a global effective formula for the modulation lag and testable predictions for the flux evolution of cosmic particles and antiparticles over the solar cycle.

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“…An important input for these calculations is the GCR proton spectrum in interstellar space (IS), J IS p . Here we have calculated the IS proton flux using an improved model of GCR acceleration and transport based on our recent works [25][26][27][28][29][30]. Using direct IS measurements from Voyager-1 and -2, in combination with high-energy data from the AMS-02 experiment [14,21,22], we derived tight constraints for the IS fluxes of GCR protons and light nuclei.…”

Section: The Data We Usedmentioning

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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Numerical modeling of cosmic-ray transport in the heliosphere and interpretation of the proton-to-helium ratio in Solar Cycle 24

Cited by 16 publications

References 53 publications

Galactic Cosmic Rays Throughout the Heliosphere and in the Very Local Interstellar Medium

Galactic Cosmic Rays Throughout the Heliosphere and in the Very Local Interstellar Medium

Temporal evolution and rigidity dependence of the solar modulation lag of Galactic cosmic rays

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

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