Correlation of Long-term Cosmic-Ray Modulation with Solar Activity Parameters

Caballero─López, R. A.; Engelbrecht, N. Eugene; Richardson, J. D.

doi:10.3847/1538-4357/ab3c57

Cited by 34 publications

(17 citation statements)

References 90 publications

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“…For up to 10 000 years the solar activity is traced with the solar modulation function, or closely related, the solar modulation potential, and is derived from the cosmogenic radionuclides 10 Be and 14 C (Abreu et al, 2013). The solar modulation potential is a term introduced to describe the effect of the strength of the solar wind with its embedded open magnetic fields on the average flux of cosmic radiation reaching the Earth (Caballero-Lopez et al, 2019). Measurements of cosmogenic radionuclides span a large time period (the last 10 000 years) but have a time resolution of only about 20 years except for the last 100 years.…”

Section: Introductionmentioning

confidence: 99%

Changes in the Total Solar Irradiance and climatic effects

Schmutz

2021

J. Space Weather Space Clim.

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The correlation between the averaged reconstructed March temperature record for Kyoto, Japan, and the reconstructed Total Solar Irradiance (TSI) irradiance over 660 years from 1230 to 1890 gives evidence with 98% probability that the Little Ice Age with four cold periods is forced by variations of TSI. If the correlation is restricted to the period 1650–1890, with two cold periods in the 17th and 19th century and for which two independent reconstructed March temperature records are available, the probability of solar forcing increases to 99.99%. As solar irradiance variations have a global effect there has to be a global climatic solar forcing impact. However, by how much global temperature were lower during these minima and with what amplitude TSI was varying is not accurately known. The two quantities, global temperature and TSI, are linked by the energy equilibrium equation for the Earth system. The derivation of this equation with respect to a variation of the solar irradiance has two terms: A direct forcing term, which can be derived analytically and quantified accurately from the Stefan-Boltzmann law, and a second term, describing indirect influences on the surface temperature. If a small TSI variation should force a large temperature variation, then it has to be the second indirect term that strongly amplifies the effect of the direct forcing. The current knowledge is summarized by three statements:During the minima periods in the 13th, 15/16th, 17th, and 19th centuries the terrestrial climate was colder by 0.5–1.5 °C;Indirect Top-down and Bottom-up mechanisms do not amplify direct forcing by a large amount, i.e. indirect solar forcing is of the same magnitude (or smaller) as direct solar forcing;The radiative output of the Sun cannot be lower by more than 2 Wm−2 below the measured present-day TSI value during solar cycle minimum.These three statements contradict each other and it is concluded that at least one is not correct. Which one is a wrong statement is presently not known conclusively. It is argued that it is the third statement and it is speculated that over centennial time scales the Sun might vary its radiance significantly more than observed so far during the last 40 years of space TSI measurements. To produce Maunder minimum type cold climate excursions, a TSI decrease of the order of 10 Wm−2 is advocated.

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Section: Introductionmentioning

confidence: 99%

Changes in the Total Solar Irradiance and climatic effects

Schmutz

2021

J. Space Weather Space Clim.

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“…Variations in intensity of cosmic rays are the consequence of the deflection of galactic cosmic rays by the time-varying solar magnetic field, which is convected away from the Sun by the solar wind [26].…”

Section: Discussionmentioning

confidence: 99%

“…The GCR intensity at Earth varies with time in response to solar activity, indicated by the sunspot number, with a period of ≈11 years; the amplitude of the variation increases with decreasing particle rigidity [26]. The transport of galactic cosmic rays in the heliosphere is well described by the cosmic ray transport equation [9].…”

Section: Discussionmentioning

confidence: 99%

Model of galactic cosmic ray spectrum above the Earth’s atmosphere

Buchvarova

Draganov

2022

J. Phys.: Conf. Ser.

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Galactic cosmic ray transport in the heliosphere is described by the well-known Parker transport equation. In 1969, Fisk and Axford [1] presented approximate analytical solutions to the cosmic ray transport equation. One of their solutions was later used to construct useful semi-empirical models describing the energy spectra of charged particles during the solar cycle. In this paper, a simplified model of the galactic cosmic ray spectrum is presented. The model can be used to describe the galactic spectra of protons and helium nuclei during the 11-year solar cycle in interplanetary space at about 1 AU.

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“…The need of inclusion of turbulence analysis when GCR characteristics are investigated was also underlined (Engelbrecht & Wolmarans 2020). Zhao et al (2018) and Caballero-Lopez et al (2019) using the spacecraft observations analyzed the turbulence properties vs solar cycle, and subsequently found the solar cycle dependence of cosmic-ray di_usion coe_cients derived from the quasi linear and nonlinear theories. This paper shows that the 27-day variations of the GCR anisotropy and intensity observed by NMs are larger in A > 0 than in A < 0 polarity.…”

Section: Discussionmentioning

confidence: 99%

Recurrence of galactic cosmic-ray intensity and anisotropy in solar minima 23/24 and 24/25 observed by ACE/CRIS, STEREO, SOHO/EPHIN and neutron monitors

Modzelewska

Gil

2021

A&A

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Aims. We studied the 27-day variations of galactic cosmic rays (GCRs) based on neutron monitor (NM), ACE/CRIS, STEREO, and SOHO/EPHIN measurements in the solar minima 23/24 and 24/25, which are characterized by the opposite polarities of solar magnetic cycle. We used the opportunity to reanalyze the polarity dependence of the amplitudes of the recurrent GCR variations in 2007–2009 for the negative A < 0 solar magnetic polarity and to compared it with the clear periodic variations related to solar rotation in 2017–2019 for positive A > 0. Methods. We used the Fourier analysis method to study the periodicity in the GCR fluxes. Because the GCR recurrence is a consequence of solar rotation, we analyzed not only GCR fluxes, but also solar and heliospheric parameters to examine the relations of the 27-day GCR variations and heliospheric as well as solar wind parameters. Results. We find that the polarity dependence of the amplitudes of the 27-day variations of the GCR intensity and anisotropy for NMs data is kept for the last two solar minima: 23/24 (2007–2009) and 24/25 (2017–2019), with greater amplitudes in the positive A > 0 solar magnetic polarity. ACE/CRIS, SOHO/EPHIN, and STEREO measurements are not governed by this principle of greater amplitudes in the positive A > 0 polarity. The GCR recurrence caused by the solar rotation for low-energy (< 1 GeV) cosmic rays is more sensitive to the enhanced diffusion effects, resulting in the same level in 27-day amplitudes for the positive and negative polarities. In contrast, the high-energy (> 1 GeV) cosmic rays that are registered by NMs are more sensitive to the large-scale drift effect, which leads to the 22-year Hale cycle in the 27-day GCR variation, with the larger amplitudes in the A > 0 polarity than in A < 0.

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Correlation of Long-term Cosmic-Ray Modulation with Solar Activity Parameters

Cited by 34 publications

References 90 publications

Changes in the Total Solar Irradiance and climatic effects

Changes in the Total Solar Irradiance and climatic effects

Model of galactic cosmic ray spectrum above the Earth’s atmosphere

Recurrence of galactic cosmic-ray intensity and anisotropy in solar minima 23/24 and 24/25 observed by ACE/CRIS, STEREO, SOHO/EPHIN and neutron monitors

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