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1

Mishra, R. A., and R. K. Mishra. "Cosmic ray modulation at neutron monitor energies." Kosmìčna nauka ì tehnologìâ 14, no. 3 (May 30, 2008): 19–28. http://dx.doi.org/10.15407/knit2008.03.019.

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2

Dorman, Lev I. "Cosmic ray modulation." Nuclear Physics B - Proceedings Supplements 22, no. 2 (July 1991): 21–45. http://dx.doi.org/10.1016/0920-5632(91)90005-y.

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3

Moraal, H. "Cosmic-Ray Modulation Equations." Space Science Reviews 176, no. 1-4 (September 24, 2011): 299–319. http://dx.doi.org/10.1007/s11214-011-9819-3.

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4

Герасимова, Сардаана, Sardaana Gerasimova, Петр Гололобов, Peter Gololobov, Владислав Григорьев, Vladislav Grigoryev, Прокопий Кривошапкин, et al. "Heliospheric modulation of cosmic rays: model and observation." Solar-Terrestrial Physics 3, no. 1 (May 5, 2017): 78–102. http://dx.doi.org/10.12737/article_58f970f2455545.93154609.

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This paper presents the basic model of cosmic ray modulation in the heliosphere, developed in Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy of the Siberian Branch of RAS. The model has only one free modulation parameter: the ratio of the regular magnetic field to the turbulent one. It may also be applied to the description of cosmic ray intensity variations in a wide energy range from 100 MeV to 100 GeV. Possible mechanisms of generation of the mentioned turbulence field are considered. The primary assumption about the electrical neutrality of the heliosphere appears to be wrong, and the zero potential needed to match the model with observations in the plane of the solar equator can be achieved if the frontal point of the heliosphere, which is flowed around by interstellar gas, lies near the mentioned plane. We have revealed that the abnormal rise of cosmic ray intensity at the end of solar cycle 23 is related to the residual modulation produced by the subsonic solar wind behind the front of a standing shock wave. The model is used to describe features of cosmic ray intensity variations in several solar activity cycles.
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5

Ferreira, Stefan E. S. "Theory of cosmic ray modulation." Proceedings of the International Astronomical Union 4, S257 (September 2008): 429–38. http://dx.doi.org/10.1017/s1743921309029664.

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AbstractThis work aims to give a brief overview on the topic of cosmic ray modulation in the heliosphere. The heliosphere, heliospheric magnetic field, transport parameters and the transport equation together with modulation models, which solve this equation in various degree of complexity, are briefly discussed. Results from these models are then presented where first it is shown how cosmic rays are globally distributed in an asymmetrical heliosphere which results from the relative motion between the local interstellar medium and the Sun. Next the focus shifts to low-energy Jovian electrons. The intensities of these electrons, which originate from a point source in the inner heliosphere, exhibit a unique three-dimensional spiral structure where most of the particles are transported along the magnetic field lines. Time-dependent modulation is also discussed where it is shown how drift effects together with propagating diffusion barriers are responsible for modulation over a solar cycle.
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6

Duldig, M. L. "Australian Cosmic Ray Modulation Research." Publications of the Astronomical Society of Australia 18, no. 1 (2001): 12–40. http://dx.doi.org/10.1071/as01003.

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AbstractAustralian research into variations of the cosmic ray flux arriving at the Earth has played a pivotal role for more than 50 years. The work has been largely led by the groups from the University of Tasmania and the Australian Antarctic Division, and has involved the operation of neutron monitors and muon telescopes from many sites. In this paper, the achievements of the Australian researchers are reviewed and future experiments are described. Particular highlights include: the determination of cosmic ray modulation parameters; the development of techniques for modelling ground-level enhancements; the confirmation of the Tail-In and Loss-Cone sidereal anisotropies; the Spaceship Earth collaboration; and the Solar Cycle latitude survey.
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7

Manuel, R., S. E. S. Ferreira, M. S. Potgieter, R. D. Strauss, and N. E. Engelbrecht. "Time-dependent cosmic ray modulation." Advances in Space Research 47, no. 9 (May 2011): 1529–37. http://dx.doi.org/10.1016/j.asr.2010.12.007.

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8

Starodubtsev, Sergei. "Shape of spectrum of galactic cosmic ray intensity fluctuations." Solar-Terrestrial Physics 8, no. 2 (June 30, 2022): 71–75. http://dx.doi.org/10.12737/stp-82202211.

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The impact of solar wind plasma on fluxes of galactic cosmic rays (CR) penetrating from the outside into the heliosphere with energies above ~1 GeV leads to temporal variations in the CR intensity in a wide frequency range. Cosmic rays being charged particles, their modulation occurs mainly under impacts of the interplanetary magnetic field. It is well known that the observed spectrum of interplanetary magnetic field (IMF) fluctuations in a wide frequency range ν from ~10–7 to ~10 Hz has a pronounced falling character and consists of three sections: energy, inertial, and dissipative. Each of them is described by the power law PIMF(ν)~ν–α, while the IMF spectrum index α increases with increasing frequency. The IMF fluctuations in each of these sections are also characterized by properties that depend on their nature. Also known are established links between fluctuation spectra of the interplanetary magnetic field and galactic cosmic rays in the case of modulation of the latter by Alfvén or fast magnetosonic waves. The theory predicts that fluctuation spectra of cosmic rays should also be described by the power law PCR(ν)~ν–γ. However, the results of many years of SHICRA SB RAS research into the nature and properties of cosmic ray intensity fluctuations based on data from neutron monitors at stations with different geomagnetic cut-offs RC from 0.5 to 6.3 GV show that the observed spectrum of fluctuations in galactic cosmic ray intensity in the frequency range above 10–4 Hz becomes flat, i.e. it is similar to white noise. This fact needs to be realized and explained. This paper reports the results of research into the shape of the spectrum of galactic cosmic ray intensity fluctuations within a frequency range ν from ~10–6 to ~1 Hz and compares them with model calculations of white noise spectra, using measurement data from the neutron monitor of the Apatity station. A possible physical explanation has been given for the observed shape of the cosmic ray fluctuation spectrum on the basis of the known mechanisms of their modulation in the heliosphere.
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9

Jokipii, J. R. "The physics of cosmic-ray modulation." Advances in Space Research 9, no. 12 (January 1989): 105–19. http://dx.doi.org/10.1016/0273-1177(89)90317-7.

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10

Mori, S. "Cosmic-ray modulation ground-based observations." Il Nuovo Cimento C 19, no. 5 (September 1996): 791–804. http://dx.doi.org/10.1007/bf02506669.

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11

Moloto, K. D., and N. Eugene Engelbrecht. "A Fully Time-dependent Ab Initio Cosmic-Ray Modulation Model Applied to Historical Cosmic-Ray Modulation." Astrophysical Journal 894, no. 2 (May 14, 2020): 121. http://dx.doi.org/10.3847/1538-4357/ab87a2.

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12

Agarwal, R., and R. Mishra. "Galactic Cosmic Ray Modulation Up to Recent Solar Cycles." Latvian Journal of Physics and Technical Sciences 48, no. 4 (January 1, 2011): 66–70. http://dx.doi.org/10.2478/v10047-011-0029-2.

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Galactic Cosmic Ray Modulation Up to Recent Solar Cycles Cosmic ray neutron monitor counts obtained by different ground-based detectors have been used to study the galactic cosmic ray modulation during the last four solar activity cycles. Since long, systematic correlative studies have been per-formed to establish a significant relationship between the cosmic ray intensity and different helio-spheric activity parameters, and the study is extended to a recent solar cycle (23). In the present work, the yearly average of 10.7 cm solar radio flux and the interplanetary magnetic field strength (IMF, B) have been used to find correlation of the yearly average cosmic ray intensity derived from different neutron monitors. It is found that for four solar cycles (20-23) the cosmic ray intensity is anti-correlated with the 10.7 cm solar radio flux and the IMF, B value with some discrepancy. However, this is in a good positive correlation with the flux of mentioned wavelength for four different solar cycles. The IMF, B shows a weak correlation with cosmic rays for solar cycle 20, and a good anti-correlation for solar cycles 21-23.
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13

Stozhkov, Yuri, Vladimir Makhmutov, and Nikolay Svirzhevsky. "About Cosmic Ray Modulation in the Heliosphere." Universe 8, no. 11 (October 26, 2022): 558. http://dx.doi.org/10.3390/universe8110558.

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Cosmic ray fluxes in the heliosphere are modulated by solar wind with an embedded solar interplanetary magnetic field. The solar activity changes with a period of ~11 year, and this is the main reason for the observed 11-year variations of cosmic ray fluxes. Besides this, the directions of magnetic fields in solar polar regions and in the heliosphere change to the opposite direction every ~11-years. This causes, in addition, the presence of another 22-year solar magnetic cycle and contributes features to the known ~11-cycle. In this article, we discuss the generally accepted picture of cosmic ray modulation in the heliosphere and show that it requires several changes.
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14

Gololobov, Peter, Prokopy Krivoshapkin, Germogen Krymsky, and Sardaana Gerasimova. "INVESTIGATING THE INFLUENCE OF GEOMETRY OF THE HELIOSPHERIC NEUTRAL CURRENT SHEET AND SOLAR ACTIVITY ON MODULATION OF GALACTIC COSMIC RAYS WITH A METHOD OF MAIN COMPONENTS." Solar-Terrestrial Physics 6, no. 1 (April 1, 2020): 24–28. http://dx.doi.org/10.12737/stp-61202002.

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The work studies the cumulative modulating effect of the geometry of the interplanetary magnetic field's neutral current sheet and solar activity on propagation of galactic cosmic rays in the heliosphere. The role of each factor on the modulation of cosmic rays is estimated using a method of main components. The application of the method to experimental data on solar activity, to the tilt angle of the neutral sheet, and cosmic ray intensity for a long period from 1980 to 2018 allows us to reveal the temporal dynamics of roles of these factors in the modulation. The modulation character is shown to strongly depend on the polarity of the Sun’s general magnetic field. Results of the study confirm the existing theoretical concepts of the heliospheric modulation of cosmic rays and reflect its peculiarities for almost four full cycles of solar activity.
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15

Gololobov, Peter, Prokopy Krivoshapkin, Germogen Krymsky, and Sardaana Gerasimova. "INVESTIGATING THE INFLUENCE OF GEOMETRY OF THE HELIOSPHERIC NEUTRAL CURRENT SHEET AND SOLAR ACTIVITY ON MODULATION OF GALACTIC COSMIC RAYS WITH A METHOD OF MAIN COMPONENTS." Solnechno-Zemnaya Fizika 6, no. 1 (March 30, 2020): 30–35. http://dx.doi.org/10.12737/szf-61202002.

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The work studies the cumulative modulating effect of the geometry of the interplanetary magnetic field's neutral current sheet and solar activity on propagation of galactic cosmic rays in the heliosphere. The role of each factor on the modulation of cosmic rays is estimated using a method of main components. The application of the method to experimental data on solar activity, to the tilt angle of the neutral sheet, and cosmic ray intensity for a long period from 1980 to 2018 allows us to reveal the temporal dynamics of roles of these factors in the modulation. The modulation character is shown to strongly depend on the polarity of the Sun’s general magnetic field. Results of the study confirm the existing theoretical concepts of the heliospheric modulation of cosmic rays and reflect its peculiarities for almost four full cycles of solar activity.
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16

Li, Jung-Tsung, John F. Beacom, and Annika H. G. Peter. "Galactic Cosmic-Ray Propagation in the Inner Heliosphere: Improved Force-field Model." Astrophysical Journal 937, no. 1 (September 1, 2022): 27. http://dx.doi.org/10.3847/1538-4357/ac8cf3.

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Abstract A key goal of heliophysics is to understand how cosmic rays propagate in the solar system’s complex, dynamic environment. One observable is solar modulation, i.e., how the flux and spectrum of cosmic rays change as they propagate inward. We construct an improved force-field model, taking advantage of new measurements of magnetic power spectral density by Parker Solar Probe to predict solar modulation within the Earth’s orbit. We find that modulation of cosmic rays between the Earth and Sun is modest, at least at solar minimum and in the ecliptic plane. Our results agree much better with the limited data on cosmic-ray radial gradients within Earth’s orbit than past treatments of the force-field model. Our predictions can be tested with forthcoming direct cosmic-ray measurements in the inner heliosphere by Parker Solar Probe and Solar Orbiter. They are also important for interpreting the gamma-ray emission from the Sun due to scattering of cosmic rays with solar matter and photons.
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17

Langner, U. W., and M. S. Potgieter. "Effects of the solar wind termination shock and heliosheath on theheliospheric modulation of galactic and anomalous Helium." Annales Geophysicae 22, no. 8 (September 7, 2004): 3063–72. http://dx.doi.org/10.5194/angeo-22-3063-2004.

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Abstract. The interest in the role of the solar wind termination shock and heliosheath in cosmic ray modulation studies has increased significantly as the Voyager 1 and 2 spacecraft approach the estimated position of the solar wind termination shock. The effect of the solar wind termination shock on charge-sign dependent modulation, as is experienced by galactic cosmic ray Helium (He++) and anomalous Helium (He+), is the main topic of this work, and is complementary to the previous work on protons, anti-protons, electrons, and positrons. The modulation of galactic and anomalous Helium is studied with a numerical model including a more fundamental and comprehensive set of diffusion coefficients, a solar wind termination shock with diffusive shock acceleration, a heliosheath and particle drifts. The model allows a comparison of modulation with and without a solar wind termination shock and is applicable to a number of cosmic ray species during both magnetic polarity cycles of the Sun. The modulation of Helium, including an anomalous component, is also done to establish charge-sign dependence at low energies. We found that the heliosheath is important for cosmic ray modulation and that its effect on modulation is very similar for protons and Helium. The local Helium interstellar spectrum may not be known at energies
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18

Ndiitwani, D. C., S. E. S. Ferreira, M. S. Potgieter, and B. Heber. "Modelling cosmic ray intensities along the Ulysses trajectory." Annales Geophysicae 23, no. 3 (March 30, 2005): 1061–70. http://dx.doi.org/10.5194/angeo-23-1061-2005.

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Abstract. Time dependent cosmic ray modulation in the inner heliosphere is studied by comparing results from a 2-D, time-dependent cosmic ray transport model with Ulysses observations. A compound approach, which combines the effects of the global changes in the heliospheric magnetic field magnitude with drifts to establish a realistic time-dependence, in the diffusion and drift coefficients, are used. We show that this model results in realistic cosmic ray modulation from the Ulysses launch (1990) until recently (2004) when compared to 2.5-GV electron and proton and 1.2-GV electron and Helium observations from this spacecraft. This approach is also applied to compute radial gradients present in 2.5-GV cosmic ray electron and protons in the inner heliosphere. The observed latitude dependence for both positive and negative charged particles during both the fast latitude scan periods, corresponding to different solar activity conditions, could also be realistically computed. For this an additional reduction in particle drifts (compared to diffusion) toward solar maximum is needed. This results in a realistic charge-sign dependent modulation at solar maximum and the model is also applied to predict charge-sign dependent modulation up to the next expected solar minimum.
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19

Storini, M., A. Antalová, and M. Jakimiec. "Cosmic-Ray Modulation and LDE-Type Flares." Journal of geomagnetism and geoelectricity 47, no. 11 (1995): 1085–91. http://dx.doi.org/10.5636/jgg.47.1085.

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20

Dumbović, M., B. Vršnak, J. Čalogović, and M. Karlica. "Cosmic ray modulation by solar wind disturbances." Astronomy & Astrophysics 531 (June 20, 2011): A91. http://dx.doi.org/10.1051/0004-6361/201016006.

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21

Guo, X., and V. Florinski. "GALACTIC COSMIC-RAY MODULATION NEAR THE HELIOPAUSE." Astrophysical Journal 793, no. 1 (August 29, 2014): 18. http://dx.doi.org/10.1088/0004-637x/793/1/18.

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22

Čalogović, Jaša, Bojan Vršnak, Manuela Temmer, and Astrid M. Veronig. "Cosmic ray modulation by corotating interaction regions." Proceedings of the International Astronomical Union 4, S257 (September 2008): 425–27. http://dx.doi.org/10.1017/s1743921309029652.

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AbstractWe analyzed the relationship between the ground-based modulation of cosmic rays (CR) and corotating interaction regions (CIRs). Daily averaged data from 8 different neutron monitor (NM) stations were used, covering rigidities from Rc = 0 − 12.91 GeV. The in situ solar wind data were taken from the Advanced Composition Explorer (ACE) database, whereas the coronal hole (CH) areas were derived from the Solar X-Ray Imager onboard GOES-12. For the analysis we have chosen a period in the declining phase of solar cycle 23, covering the period 25 January–5 May 2005. During the CIR periods CR decreased typically from 0.5% to 2%. A cross-correlation analysis showed a distinct anti-correlation between the magnetic field and CR, with the correlation coefficient (r) ranging from −0.31 to −0.38 (mean: −0.36) and with the CR time delay of 2 to 3 days. Similar anti-correlations were found for the solar wind density and velocity characterized by the CR time lag of 4 and 1 day, respectively. The relationship was also established between the CR modulation and the area of the CIR-related CH with the CR time lag of 5 days after the central-meridian passage of CH.
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23

Ahluwalia, H. S. "IMF intensity and galactic cosmic ray modulation." Advances in Space Research 29, no. 3 (January 2002): 439–44. http://dx.doi.org/10.1016/s0273-1177(01)00609-3.

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24

Engelbrecht, N. E., and R. A. Burger. "Cosmic-Ray Modulation: an Ab Initio Approach." Brazilian Journal of Physics 44, no. 5 (September 4, 2014): 512–19. http://dx.doi.org/10.1007/s13538-014-0241-7.

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25

Cliver, E. W., W. Dröge, and R. Müller-Mellin. "Superevents and cosmic ray modulation, 1974-1985." Journal of Geophysical Research 98, A9 (1993): 15231. http://dx.doi.org/10.1029/93ja00645.

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26

Xanthakis, J., H. Mavromichalaki, and B. Petropoulos. "Time-evolution of cosmic-ray intensity modulation." Solar Physics 122, no. 2 (1989): 345–63. http://dx.doi.org/10.1007/bf00913001.

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27

Le Roux, J. A., and M. S. Potgieter. "Episodic cosmic-ray modulation in the heliosphere." Advances in Space Research 9, no. 4 (January 1989): 225–28. http://dx.doi.org/10.1016/0273-1177(89)90118-x.

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28

Kunow, H. "Solar cycle modulation of cosmic ray electrons." Advances in Space Research 16, no. 9 (January 1995): 349. http://dx.doi.org/10.1016/0273-1177(95)00363-j.

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29

Mishra, Rajesh K., and Rekha Agarwal Mishra. "Interplanetary magnetic clouds and cosmic ray modulation." Astrophysics 50, no. 4 (October 2007): 533–43. http://dx.doi.org/10.1007/s10511-007-0049-z.

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30

Florinski, V., W. I. Axford, and G. P. Zank. "The Cosmic Ray Increases At 35 and 60 Kyr BP." Radiocarbon 46, no. 2 (2004): 683–90. http://dx.doi.org/10.1017/s0033822200035736.

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Concentrations of 10Be in ice cores and marine sediments exhibit 2 peaks with significant enhancements at 35,000 and 60,000 BP. This radioisotope is produced in the upper atmosphere by spallation of cosmic-ray protons and secondary neutrons on atmospheric nitrogen and oxygen. Previously suggested explanations for the increases include geomagnetic field reversals, a decrease in solar activity, and a supernova explosion. We propose an alternative explanation which involves a change in the galactic environment of the solar system. The structure of the heliosphere is investigated for a period when the Sun enters a cold, dense, unmagnetized interstellar cloud. Under these conditions, the heliosphere contracts to 25% its present size, significantly affecting galactic cosmic ray modulation and increasing anomalous cosmic ray fluxes. A tenfold increase in anomalous cosmic ray flux and a twofold increase in galactic cosmic ray intensity at Earth are possible in this high-density case if heliosheath modulation is reduced. We show that this increase in galactic cosmic ray intensity could be responsible for the peaks in 10Be records.
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31

Герасимова, Сардаана, Sardaana Gerasimova, Петр Гололобов, Peter Gololobov, Владислав Григорьев, Vladislav Grigoryev, Прокопий Кривошапкин, et al. "Heliospheric modulation of cosmic rays: model and observation." Solnechno-Zemnaya Fizika 3, no. 1 (April 17, 2017): 63–78. http://dx.doi.org/10.12737/23548.

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This paper presents the basic model of cosmic ray modulation in the heliosphere, developed in Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy of the Siberian Branch of RAS. The model has only one free modulation parameter: the ratio of the regular magnetic field to the turbulent one. It may also be applied to the description of cosmic ray intensity variations in a wide energy range from 100 MeV to 100 GeV. Possible mechanisms of generation of the mentioned turbulence field are considered. The primary assumption about the electrical neutrality of the heliosphere appears to be wrong, and the zero potential needed to match the model with observations in the plane of the solar equator can be achieved if the frontal point of the heliosphere, which is flowed around by interstellar gas, lies near the mentioned plane. We have revealed that the abnormal rise of cosmic ray intensity at the end of solar cycle 23 is related to the residual modulation produced by the subsonic solar wind behind the front of a standing shock wave. The model is used to describe features of cosmic ray intensity variations in several solar activity cycles.
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32

Ferreira, S. E. S., M. S. Potgieter, B. Heber, and H. Fichtner. "Charge-sign dependent modulation in the heliosphere over a 22-year cycle." Annales Geophysicae 21, no. 6 (June 30, 2003): 1359–66. http://dx.doi.org/10.5194/angeo-21-1359-2003.

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Abstract. A time-dependent model based on a numerical solution of Parker’s transport equation is used to model the modulation of cosmic ray protons, electrons and helium for full 11-year and 22-year modulation cycles using a compound approach. This approach incorporates the concept of propagating diffusion barriers based on global increases in the heliospheric magnetic field as they propagate from the Sun throughout the heliosphere, combined with gradient, curvature and current sheet drifts and the other basic modulation mechanisms. The model results are compared to the observed 11-year and 22-year cycles for 1.2 GV electrons and 1.2 GV Helium at Earth for the period 1975–1998. The model solutions are also compared to the observed charge-sign dependent modulation along Ulysses’ trajectory for the period 1990–1998. This compound approach to long-term modulation, especially charge-sign dependent modulation, is found to be remarkably successful. It is shown that the model can easily account for the latitude dependence for cosmic ray protons and the lack thereof for cosmic ray electrons by assuming large perpendicular diffusion in the polar direction. This approach contributes to an improved understanding of how diffusion and drifts vary from solar minimum to maximum modulation, and what the time-dependence of the heliospheric diffusion coefficients may be. Key words. Interplanetary physics (energetic particles; cosmic rays; general or miscellaneous)
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33

Pérez-Peraza, Jorge, Víctor Velasco, Igor Ya Libin, and K. F. Yudakhin. "Thirty-Year Periodicity of Cosmic Rays." Advances in Astronomy 2012 (2012): 1–11. http://dx.doi.org/10.1155/2012/691408.

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Cosmogenic isotopes have frequently been employed as proxies of ancient cosmic ray fluxes. On the basis of periodicities of the10Be time series (using data from both the South and North Poles) and the14C time series (with data from Intercal-98), we offer evidence of the existence of cosmic ray fluctuations with a periodicity of around 30 years. Results were obtained by using the wavelet transformation spectral technique, signal reconstruction by autoregressive spectral analysis (ARMA), and the Lomb-Scargle periodogram method. This 30-year periodicity seems to be significant in nature because several solar and climatic indexes exhibit the same modulation, which may indicate that the 30-year frequency of cosmic rays is probably a modulator agent for terrestrial phenomena, reflecting the control source, namely, solar activity.
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34

Starodubtsev, S. A., I. G. Usoskin, A. V. Grigoryev, and K. Mursula. "Long-term modulation of the cosmic ray fluctuation spectrum." Annales Geophysicae 24, no. 2 (March 23, 2006): 779–83. http://dx.doi.org/10.5194/angeo-24-779-2006.

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Abstract. Here we study the power level of rapid cosmic ray fluctuations in the frequency range of 10-4-1.67·10-3 Hz (periods from 10 min to about 3 h), using measurements by space-borne instruments for the period since 1974. We find that the power level of these fluctuations varies over the solar cycle, but the phase of this variation depends on the energy of cosmic ray particles. While the power level of these fluctuations in the higher energy channels (corresponding to galactic cosmic rays) changes in phase with the solar cycle, the fluctuation level for lower energy channels (predominantly of solar/interplanetary origin) is roughly in an opposite phase with the solar cycle. The results prove conclusively that these fluctuations originate in the near-Earth space, excluding their atmospheric or magnetospheric origin. We present these new results and discuss a possible scenario explaining the observed energy-dependence.
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35

Shaikh, Zubair I., Anil N. Raghav, and Geeta Vichare. "Evolution of planar magnetic structure within the stream interaction region and its connection with a recurrent Forbush decrease." Monthly Notices of the Royal Astronomical Society 494, no. 4 (May 7, 2020): 5075–80. http://dx.doi.org/10.1093/mnras/staa1039.

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ABSTRACT In general, stream interaction region (SIR)-induced Forbush decreases are recurrent and low magnitude in nature. The diffusion–convection associated with the SIR plays an important role in their modulation. Here, we study the evolution of planar magnetic structure (PMS) within the SIR and its contribution to cosmic ray modulation. Interestingly, we found the presence of PMS structures within the SIR from the leading part of the SIR to the minimum of the cosmic ray intensity in two events. The PMS may have originated due to the high compression caused by the fast solar wind, which amplifies and aligns the pre-existing discontinuities in the ambient slow solar wind. The study also suggests that the existence of PMS, enhanced initial mass function (IMF) strength, and associated turbulent regions decreases the perpendicular diffusion coefficient and causes a decrease in the cosmic ray intensity observed on Earth. Moreover, a slow decrease in IMF magnitude concurs with the recovery phase of cosmic ray intensity.
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36

Hasebe, N., K. Kondoh, M. Kobayashi, Y. Mishima, T. Doke, J. Kikuchi, T. Hayashi, et al. "Corotating Ion Events Associated with Cosmic Ray Modulation." Journal of geomagnetism and geoelectricity 47, no. 12 (1995): 1333–38. http://dx.doi.org/10.5636/jgg.47.1333.

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37

Randall, B. A., and J. A. Van Allen. "Heliocentric radius of the cosmic ray modulation boundary." Geophysical Research Letters 13, no. 7 (July 1986): 628–31. http://dx.doi.org/10.1029/gl013i007p00628.

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Lara, A., N. Gopalswamy, R. A. Caballero‐Lopez, S. Yashiro, H. Xie, and J. F. Valdes‐Galicia. "Coronal Mass Ejections and Galactic Cosmic‐Ray Modulation." Astrophysical Journal 625, no. 1 (May 20, 2005): 441–50. http://dx.doi.org/10.1086/428565.

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Cane, H. V., G. Wibberenz, I. G. Richardson, and T. T. von Rosenvinge. "Cosmic ray modulation and the solar magnetic field." Geophysical Research Letters 26, no. 5 (March 1, 1999): 565–68. http://dx.doi.org/10.1029/1999gl900032.

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Feynman, J., and A. Ruzmaikin. "Modulation of cosmic ray precipitation related to climate." Geophysical Research Letters 26, no. 14 (July 15, 1999): 2057–60. http://dx.doi.org/10.1029/1999gl900326.

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Ferreira, S. E. S., and M. S. Potgieter. "Long‐Term Cosmic‐Ray Modulation in the Heliosphere." Astrophysical Journal 603, no. 2 (March 10, 2004): 744–52. http://dx.doi.org/10.1086/381649.

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Engelbrecht, N. E., and R. A. Burger. "AN AB INITIO MODEL FOR COSMIC-RAY MODULATION." Astrophysical Journal 772, no. 1 (July 5, 2013): 46. http://dx.doi.org/10.1088/0004-637x/772/1/46.

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Laurenza, M., A. Vecchio, M. Storini, and V. Carbone. "DRIFT EFFECTS ON THE GALACTIC COSMIC RAY MODULATION." Astrophysical Journal 781, no. 2 (January 10, 2014): 71. http://dx.doi.org/10.1088/0004-637x/781/2/71.

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Burlaga, L. F., J. Perko, and J. Pirraglia. "Cosmic-ray modulation, merged interaction regions, and multifractals." Astrophysical Journal 407 (April 1993): 347. http://dx.doi.org/10.1086/172517.

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Ahluwalia, H. S., C. Lopate, R. C. Ygbuhay, and M. L. Duldig. "Galactic cosmic ray modulation for sunspot cycle 23." Advances in Space Research 46, no. 7 (October 2010): 934–41. http://dx.doi.org/10.1016/j.asr.2010.04.008.

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McKibben, R. B., J. J. Connell, C. Lopate, J. A. Simpson, and M. Zhang. "Cosmic ray modulation in the 3-D heliosphere." Space Science Reviews 72, no. 1-2 (April 1995): 367–78. http://dx.doi.org/10.1007/bf00768807.

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Storini, M. "Galactic cosmic-ray modulation and solar-terrestrial relationships." Il Nuovo Cimento C 13, no. 1 (January 1990): 103–24. http://dx.doi.org/10.1007/bf02515780.

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Storini, M., O. Borello-Filisetti, V. Mussino, M. Parisi, and J. S�kora. "Aspects of the long-term cosmic-ray modulation." Solar Physics 157, no. 1-2 (March 1995): 375–87. http://dx.doi.org/10.1007/bf00680628.

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Quenby, J. J., B. Drolias, E. Keppler, M. K. Reuss, and J. B. Blake. "Cosmic ray modulation by expanding, high-latitude streams." Geophysical Research Letters 22, no. 23 (December 1, 1995): 3345–48. http://dx.doi.org/10.1029/95gl03543.

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Paouris, Evangelos. "Ineffectiveness of Narrow CMEs for Cosmic Ray Modulation." Solar Physics 284, no. 2 (November 2, 2012): 589–97. http://dx.doi.org/10.1007/s11207-012-0166-7.

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