Systematic Investigation of Solar Modulation of Galactic Protons for Solar Cycle 23 Using a Monte Carlo Approach With Particle Drift Effects and Latitudinal Dependence

Bobík, P.; Boella, G.; Boschini, M.; Consolandi, C.; Torre, S. Della; Gervasi, M.; Grandi, D.; Kudela, K.; Pensotti, S.; Rancoita, P.G.; Tacconi, M.

doi:10.1088/0004-637x/745/2/132

Cited by 70 publications

(130 citation statements)

References 134 publications

(199 reference statements)

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“…Besides it is important that (2) in the first 20 years (1955-1975) it was believed that there was only the 11-year sunspot cycle in the heliospheric parameters and there was not any dominating HMF polarity A (the sign the regular HMF radial component B hm f r in the N-hemisphere). After that J 22 (t) is considered as small variation with respect to J 11 (t) as (3) the Earth is not in a favorable position to observe the drift effects [28].…”

Section: On Different Points Of Viewmentioning

confidence: 99%

“…The questions of how the drift and other processes influence the propagation times and energy losses in the heliosphere were addressed in [32] also using SDE approach. The same method was used in [2] also changing one factor at a time (switching on and off the drift term and modifying the diffusion tensor) in multiple runs.…”

Section: Pos(icrc2015)176mentioning

confidence: 99%

“…Note that in all models [30,36,2], studying the contribution of different mechanisms by the method of multiple runs changing only one of the factors at a time, the overall distribution of the intensity gradients for each such run is not the same as it is in the run with all the modulating factors changing in time simultaneously. This difference in the intensity gradients can be very significant and so the diffusion, drift and convection of the particles, that is all the processes depending on the gradients, carry out differently in each of the runs.…”

Section: Pos(icrc2015)176mentioning

confidence: 99%

“…The contribution of different mechanisms to the solar modulation of the GCR intensity was also scrutinized in several recent papers (see [2,13,18,36,30]). Besides, recently a new numerical tool was suggested to disentangle the effects of all the individual mechanisms from the…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

On the causes and mechanisms of the long-term variations in the GCR characteristics

Крайнев¹,

Kóta²,

Potgieter³

2016

Proceedings of the 34th International Cosmic Ray Conference — PoS(ICRC2015)

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We argue that the degree of understanding the causes and mechanisms of the long-term variations (11-year and 22-year) in the galactic cosmic rays (GCR) characteristics is still insufficient and to improve it we need new approaches and methods. For the time being there is a long-lasting controversy on how these long-term variations, observed for more than 50 years in the inner heliosphere, are formed. It is widely believed that the 11-year variation is due entirely to the toroidal branch of solar activity (the area and number of sunspots, the strength of the heliospheric magnetic field etc) because of the diffusion, convection and adiabatic energy loss, while the much smaller 22-year variation is caused by the particle drifts connected with the poloidal branch of solar activity (the high-latitude solar magnetic fields). At the same time, both past and more recent numerical simulations indicate that the contribution of particle drifts could be significant for both 22-and 11-year variations in the GCR intensities. However, even those who agree on the significant influence of drifts appear to have different perceptions on the mechanisms of this influence. In this paper, we present an analysis of the possible causes of the first point of view (small role of drifts in the 11-year GCR variation) and the reasons why one can expect the significant contribution of the processes connected with the poloidal branch of solar activity in both types of the long-term variations of the GCR characteristics. Then we briefly discuss some numerical methods suggested in the past and recently and the approaches and perspectives for the sought-for methods are considered.

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Section: On Different Points Of Viewmentioning

confidence: 99%

Section: Pos(icrc2015)176mentioning

confidence: 99%

Section: Pos(icrc2015)176mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

On the causes and mechanisms of the long-term variations in the GCR characteristics

Крайнев¹,

Kóta²,

Potgieter³

2016

Proceedings of the 34th International Cosmic Ray Conference — PoS(ICRC2015)

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“…We use a recently developed version of a 2D Monte Carlo code for heliospheric propagation HelMod 2 [23][24][25] combined with GALPROP to take advantage of a significant progress in CR measurements to derive the LIS for protons, helium and antiprotons. The HelMod model includes all relevant effects and, thus, a full description of the diffusion tensor.…”

Section: Introductionmentioning

confidence: 99%

Inside out: unveiling local interstellar spectra of cosmic ray species

Boschini¹,

Torre²,

Gervasi³

et al. 2017

Proceedings of 35th International Cosmic Ray Conference — PoS(ICRC2017)

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Local interstellar spectra (LIS) for protons, helium and antiprotons are built using the most recent experimental results combined with state-of-the-art models for propagation in the Galaxy and Heliosphere. Two propagation packages, GALPROP and HelMod, are combined to provide a single framework that is run to reproduce direct measurements of cosmic ray (CR) species at different modulation levels and at both polarities of the solar magnetic field. To do so in a selfconsistent way, an iterative procedure was developed, where the GALPROP LIS output is fed into HelMod that provides modulated spectra for specific time periods of selected experiments to compare with the data. The parameters were tuned with a maximum likelihood procedure using an extensive data set of proton spectra from 1997-2015. The proposed LIS accommodate both the low energy interstellar CR spectra measured by Voyager 1 and the high energy observations by BESS, PAMELA, AMS-01, and AMS-02 made from the balloons and near-Earth payloads. The proton LIS also accounts for Ulysses counting rate features measured out of the ecliptic plane. The obtained solution is in a good agreement with proton, helium, and antiproton data by AMS-02, BESS, and PAMELA in the whole energy range.

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On the forward‐backward‐in‐time approach for Monte Carlo solution of Parker's transport equation: One‐dimensional case

et al. 2016

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The cosmic rays propagation inside the heliosphere is well described by a transport equation introduced by Parker in 1965. To solve this equation, several approaches were followed in the past. Recently, a Monte Carlo approach became widely used in force of its advantages with respect to other numerical methods. In this approach the transport equation is associated to a fully equivalent set of stochastic differential equations (SDE). This set is used to describe the stochastic path of quasi‐particle from a source, e.g., the interstellar space, to a specific target, e.g., a detector at Earth. We present a comparison of forward‐in‐time and backward‐in‐time methods to solve the cosmic rays transport equation in the heliosphere. The Parker equation and the related set of SDE in the several formulations are treated in this paper. For the sake of clarity, this work is focused on the one‐dimensional solutions. Results were compared with an alternative numerical solution, namely, Crank‐Nicolson method, specifically developed for the case under study. The methods presented are fully consistent each others for energy greater than 400 MeV. The comparison between stochastic integrations and Crank‐Nicolson allows us to estimate the systematic uncertainties of Monte Carlo methods. The forward‐in‐time stochastic integrations method showed a systematic uncertainty <5%, while backward‐in‐time stochastic integrations method showed a systematic uncertainty <1% in the studied energy range.

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Systematic Investigation of Solar Modulation of Galactic Protons for Solar Cycle 23 Using a Monte Carlo Approach With Particle Drift Effects and Latitudinal Dependence

Cited by 70 publications

References 134 publications

On the causes and mechanisms of the long-term variations in the GCR characteristics

On the causes and mechanisms of the long-term variations in the GCR characteristics

Inside out: unveiling local interstellar spectra of cosmic ray species

On the forward‐backward‐in‐time approach for Monte Carlo solution of Parker's transport equation: One‐dimensional case

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