Main journal articles on HelMod model and code
M J Boschini, G Cavallotto, S Della Torre, M Gervasi, G La Vacca, P G Rancoita and M Tacconi.
Fast and accurate evaluation of deep-space galactic cosmic ray fluxes with HelMod-4/CUDA.
Advances in Space Research (in press), April 2024.
Abstract The accurate knowledge of cosmic ion fluxes is essential for fundamental physics, deep space missions, and exploration activities in the solar system. In the HelMod-4 model the Parker transport equation is solved using a Monte Carlo approach to evaluate the solar modulation effect on local interstellar spectra of Galactic Cosmic Rays (GCRs). This work presents the latest updates to the HelMod-4 model parameters, focusing on the descending phase of solar cycle 24. The updates are motivated by the latest high-precision measurements from the AMS-02 detector which revealed for the first time with high accuracy the features of GCR fluxes’ evolution during a period of positive interplanetary magnetic field polarity. Furthermore, we present HelMod-4/CUDA, a GPU-accelerated approach for solving the Parker equation in the heliosphere using a stochastic differential equation method. The code is an evolution of the HelMod-4 code, porting the algorithm to GPU architecture using the CUDA programming language. This approach achieves significant speedup compared to a CPU implementation. The HelMod-4/CUDA code has been validated by comparing its results with the most precise and updated experimental GCR spectra observed during high and low solar activity periods, both in the inner and outer heliosphere, at the Earth location, and outside the ecliptic plane. The comparison shows that HelMod-4 and HelMod-4/CUDA can be equivalently used to provide solar-modulated spectra with a similar degree of accuracy in reproducing observed data
BibTeX@article{BOSCHINI2024, title = "Fast and accurate evaluation of deep-space galactic cosmic ray fluxes with HelMod-4/CUDA", journal = "Advances in Space Research (in press)", month = "April", year = 2024, author = "Boschini, M.J. and Cavallotto, G. and {Della Torre}, S. and Gervasi, M. and {La Vacca},G. and Rancoita, P.G. and Tacconi, M.", abstract = "The accurate knowledge of cosmic ion fluxes is essential for fundamental physics, deep space missions, and exploration activities in the solar system. In the HelMod-4 model the Parker transport equation is solved using a Monte Carlo approach to evaluate the solar modulation effect on local interstellar spectra of Galactic Cosmic Rays (GCRs). This work presents the latest updates to the HelMod-4 model parameters, focusing on the descending phase of solar cycle 24. The updates are motivated by the latest high-precision measurements from the AMS-02 detector which revealed for the first time with high accuracy the features of GCR fluxes’ evolution during a period of positive interplanetary magnetic field polarity. Furthermore, we present HelMod-4/CUDA, a GPU-accelerated approach for solving the Parker equation in the heliosphere using a stochastic differential equation method. The code is an evolution of the HelMod-4 code, porting the algorithm to GPU architecture using the CUDA programming language. This approach achieves significant speedup compared to a CPU implementation. The HelMod-4/CUDA code has been validated by comparing its results with the most precise and updated experimental GCR spectra observed during high and low solar activity periods, both in the inner and outer heliosphere, at the Earth location, and outside the ecliptic plane. The comparison shows that HelMod-4 and HelMod-4/CUDA can be equivalently used to provide solar-modulated spectra with a similar degree of accuracy in reproducing observed data" }M J Boschini, S Della Torre, M Gervasi, D Grandi, G Jóhannesson, G La Vacca, N Masi, I V Moskalenko, S Pensotti, T A Porter, L Quadrani, P G Rancoita, D Rozza and M Tacconi.
Spectra of Cosmic Ray Sodium and Aluminum and Unexpected Aluminum Excess.
The Astrophysical Journal 933(2):147, January 2022.
URL, DOI BibTeX@article{2022AlNa, author = "{Boschini}, M.J. and {Della Torre}, S. and {Gervasi}, M. and {Grandi}, D. and J{\'{o}}hannesson, G. and {La Vacca}, G. and {Masi}, N. and {Moskalenko}, I.V. and {Pensotti}, S. and {Porter}, T.A. and {Quadrani}, L. and {Rancoita}, P.G. and {Rozza}, D. and {Tacconi}, M.", title = "Spectra of Cosmic Ray Sodium and Aluminum and Unexpected Aluminum Excess", doi = "10.3847/1538-4357/ac7443", year = 2022, month = "jan", publisher = "American Astronomical Society", volume = 933, number = 2, pages = 147, journal = "The Astrophysical Journal", url = "https://arxiv.org/abs/2202.09928", hmwp = "AllP,LIS", aname = "BoschiniEtAl2022d" }M J Boschini, S Della Torre, M Gervasi, G La Vacca and P G Rancoita.
The transport of galactic cosmic rays in heliosphere: The HelMod model compared with other commonly employed solar modulation models.
Advances in Space Research 70(9):2636-2648, 2022.
Abstract HelMod model allows one to describe how solar modulation affects the propagation of galactic cosmic rays (GCRs) through the heliosphere by solving the Parker transport equation. HelMod provides modulated spectra for protons and nuclei during high and low solar activity periods, in the inner and outer heliosphere, at Earth location and outside the ecliptic plane, as well as at different distances from Sun in the inner and outer heliosphere. The GCRs mainly constitute the high-energy population of the so-called space radiation environment. Modulated cosmic-ray spectra of protons and nuclei, obtained from HelMod and other solar modulation codes were compared to the AMS-02 spectra ranging from GeV up to TeV energies. Concerning other commonly used solar modulation models, HelMod modulated spectra are available over the entire rigidity range and observation period of AMS-02 mission. A quantitative comparison among models was carried out using $\Delta¶hi$, i.e., the relative difference between the experimental and simulated fluences, and $\eta_RMS$, i.e., the error-weighted root mean square of the relative difference between AMS-02 experimental data and simulated differential intensities. HelMod was found to achieve a good agreement over the full set of experimental data with, typically, $\Delta¶hi$ within $\pm$2.5% and $\eta_RMS$ within 5%. Usually larger or, in a few cases, much larger values for $\Delta¶hi$ and $\eta_RMS$ were found for the other models.
URL, DOI BibTeX@article{BOSCHINI2022c, title = "The transport of galactic cosmic rays in heliosphere: The HelMod model compared with other commonly employed solar modulation models", journal = "Advances in Space Research", volume = 70, number = 9, pages = "2636-2648", year = 2022, issn = "0273-1177", doi = "10.1016/j.asr.2022.03.026", url = "https://www.sciencedirect.com/science/article/pii/S0273117722002125", author = "Boschini, M.J. and {Della Torre}, S. and Gervasi, M. and {La Vacca},G. and Rancoita, P.G.", keywords = "Solar modulation, Interplanetary space, Cosmic ray propagation, Space radiation environment", abstract = "HelMod model allows one to describe how solar modulation affects the propagation of galactic cosmic rays (GCRs) through the heliosphere by solving the Parker transport equation. HelMod provides modulated spectra for protons and nuclei during high and low solar activity periods, in the inner and outer heliosphere, at Earth location and outside the ecliptic plane, as well as at different distances from Sun in the inner and outer heliosphere. The GCRs mainly constitute the high-energy population of the so-called space radiation environment. Modulated cosmic-ray spectra of protons and nuclei, obtained from HelMod and other solar modulation codes were compared to the AMS-02 spectra ranging from GeV up to TeV energies. Concerning other commonly used solar modulation models, HelMod modulated spectra are available over the entire rigidity range and observation period of AMS-02 mission. A quantitative comparison among models was carried out using $\Delta\Phi$, i.e., the relative difference between the experimental and simulated fluences, and $\eta_{RMS}$, i.e., the error-weighted root mean square of the relative difference between AMS-02 experimental data and simulated differential intensities. HelMod was found to achieve a good agreement over the full set of experimental data with, typically, $\Delta\Phi$ within $\pm$2.5\% and $\eta_{RMS}$ within 5\%. Usually larger or, in a few cases, much larger values for $\Delta\Phi$ and $\eta_{RMS}$ were found for the other models.", hmwp = "AllP", aname = "BoschiniEtAl2022c" }M J Boschini, S Della Torre, M Gervasi, G La Vacca and P G Rancoita.
Forecasting of cosmic rays intensities with HelMod Model.
Advances in Space Research 70(9):2649-2657, 2022.
Abstract HelMod model allows one to describe how solar modulation affects the propagation of galactic cosmic rays (GCR) through the heliosphere with an accuracy of the level of actual experimental uncertainties. The GCRs mainly constitute the high energy population of the so-called space radiation environment. The model treats the physical processes involved in solar modulation, like diffusion, particle drift, convection and adiabatic energy losses, and it embeds a description of both the inner and outer heliosphere. To obtain the modulated intensities, the model requires the knowledge of a few time-dependent heliospheric quantities, i.e., sunspot number, tilt angle of the neutral current sheet, solar wind speed and density, and interplanetary magnetic field. Using historical records, we present a template-based procedure that allows one to predict the heliospheric parameters for coming years, and, in turn, the forecasted modulated spectra. The forecasting templates reconstruct the typical time variation along with solar cycles and may be tuned to the current solar cycle. We estimate that the uncertainty of the forecasted cosmic rays intensity is below 5% ($\pm$10% at 68% C.L.) on average for short time predictions (up to 4 years), and below 15% ($\pm$(20 – 25)% at 68% C.L.) for long time predictions (up to 11 years).
URL, DOI BibTeX@article{BOSCHINI2022b, title = "Forecasting of cosmic rays intensities with HelMod Model", journal = "Advances in Space Research", volume = 70, number = 9, pages = "2649-2657", year = 2022, issn = "0273-1177", doi = "10.1016/j.asr.2022.01.031", author = "Boschini, M.J. and {Della Torre}, S. and Gervasi, M. and {La Vacca},G. and Rancoita, P.G.", keywords = "solar modulation; interplanetary space; Cosmic rays; space weather; sunspot number; space radiation environment; Forecast", abstract = "HelMod model allows one to describe how solar modulation affects the propagation of galactic cosmic rays (GCR) through the heliosphere with an accuracy of the level of actual experimental uncertainties. The GCRs mainly constitute the high energy population of the so-called space radiation environment. The model treats the physical processes involved in solar modulation, like diffusion, particle drift, convection and adiabatic energy losses, and it embeds a description of both the inner and outer heliosphere. To obtain the modulated intensities, the model requires the knowledge of a few time-dependent heliospheric quantities, i.e., sunspot number, tilt angle of the neutral current sheet, solar wind speed and density, and interplanetary magnetic field. Using historical records, we present a template-based procedure that allows one to predict the heliospheric parameters for coming years, and, in turn, the forecasted modulated spectra. The forecasting templates reconstruct the typical time variation along with solar cycles and may be tuned to the current solar cycle. We estimate that the uncertainty of the forecasted cosmic rays intensity is below 5\% ($\pm$10\% at 68\% C.L.) on average for short time predictions (up to 4 years), and below 15\% ($\pm$(20 -- 25)\% at 68\% C.L.) for long time predictions (up to 11 years).", url = "http://www.helmod.org/DownloadArea/2021_Forecasts.pdf", hmwp = "AllP", aname = "BoschiniEtAl2022b" }M J Boschini, S Della Torre, M Gervasi, D Grandi, G Jóhannesson, G La Vacca, N Masi, I V Moskalenko, S Pensotti, T A Porter, L Quadrani, P G Rancoita, D Rozza and M Tacconi.
A Hint of a Low-energy Excess in Cosmic-Ray Fluorine.
The Astrophysical Journal 925(2):108, January 2022.
Abstract Since its launch, the Alpha Magnetic Spectrometer–02 (AMS-02) has delivered outstanding quality measurements of the spectra of cosmic-ray (CR) species ($\bar p$, e$^\pm$) and nuclei (H–O, Ne, Mg, Si, Fe), which resulted in a number of breakthroughs. The most recent AMS–02 result is the measurement of the spectrum of CR fluorine up to $\sim$2 TV. Given its very low solar system abundance, fluorine in CRs is thought to be mostly secondary, produced in fragmentations of heavier species, predominantly Ne, Mg, and Si. Similar to the best-measured secondary-to-primary boron to carbon nuclei ratio that is widely used to study the origin and propagation of CR species, the precise fluorine data would allow the origin of Si-group nuclei to be studied independently. Meanwhile, the secondary origin of CR fluorine has never been tested in a wide energy range due to the lack of accurate CR data. In this paper, we use the first ever precise measurements of the fluorine spectrum by AMS-02 together with ACE-CRIS and Voyager 1 data to actually test this paradigm. Our detailed modeling shows an excess below 10 GV in the fluorine spectrum that may hint at a primary fluorine component. We also provide an updated local interstellar spectrum (LIS) of fluorine in the rigidity range from a few MV to $\sim$2 TV. Our calculations employ the self-consistent GalProp–HelMod framework that has proved to be a reliable tool in deriving the LIS of CR and e$^-$, and nuclei Z $łeq$ 28.
URL, DOI BibTeX@article{Boschini_2022, doi = "10.3847/1538-4357/ac313d", url = "https://arxiv.org/abs/2106.01626", eprint = "2106.01626", archiveprefix = "arXiv", primaryclass = "astro-ph.HE", year = 2022, month = "jan", publisher = "American Astronomical Society", volume = 925, number = 2, pages = 108, journal = "The Astrophysical Journal", author = "{Boschini}, M.J. and {Della Torre}, S. and {Gervasi}, M. and {Grandi}, D. and J{\'{o}}hannesson, G. and {La Vacca}, G. and {Masi}, N. and {Moskalenko}, I.V. and {Pensotti}, S. and {Porter}, T.A. and {Quadrani}, L. and {Rancoita}, P.G. and {Rozza}, D. and {Tacconi}, M.", title = "A Hint of a Low-energy Excess in Cosmic-Ray Fluorine", abstract = "Since its launch, the Alpha Magnetic Spectrometer–02 (AMS-02) has delivered outstanding quality measurements of the spectra of cosmic-ray (CR) species ($\bar p$, e$^\pm$) and nuclei (H--O, Ne, Mg, Si, Fe), which resulted in a number of breakthroughs. The most recent AMS--02 result is the measurement of the spectrum of CR fluorine up to $\sim$2 TV. Given its very low solar system abundance, fluorine in CRs is thought to be mostly secondary, produced in fragmentations of heavier species, predominantly Ne, Mg, and Si. Similar to the best-measured secondary-to-primary boron to carbon nuclei ratio that is widely used to study the origin and propagation of CR species, the precise fluorine data would allow the origin of Si-group nuclei to be studied independently. Meanwhile, the secondary origin of CR fluorine has never been tested in a wide energy range due to the lack of accurate CR data. In this paper, we use the first ever precise measurements of the fluorine spectrum by AMS-02 together with ACE-CRIS and Voyager 1 data to actually test this paradigm. Our detailed modeling shows an excess below 10 GV in the fluorine spectrum that may hint at a primary fluorine component. We also provide an updated local interstellar spectrum (LIS) of fluorine in the rigidity range from a few MV to $\sim$2 TV. Our calculations employ the self-consistent GalProp--HelMod framework that has proved to be a reliable tool in deriving the LIS of CR and e$^-$, and nuclei Z $\leq$ 28.", hmwp = "AllP,LIS", aname = "BoschiniEtAl2022a" }M J Boschini, S Della Torre, M Gervasi, D Grandi, G Jóhannesson, G La Vacca, N Masi, I V Moskalenko, S Pensotti, T A Porter, L Quadrani, P G Rancoita, D Rozza and M Tacconi.
The Discovery of a Low-energy Excess in Cosmic-Ray Iron: Evidence of the Past Supernova Activity in the Local Bubble.
The Astrophysical Journal 913(1):5, May 2021.
Abstract Since its launch, the Alpha Magnetic Spectrometer—02 (AMS-02) has delivered outstanding quality measurements of the spectra of cosmic-ray (CR) species (p, e ±, and nuclei, 1H–8O, 10Ne, 12Mg, 14Si) which resulted in a number of breakthroughs. One of the latest long-awaited surprises is the spectrum of 26Fe just published by AMS-02. Because of the large fragmentation cross section and large ionization energy losses, most of CR iron at low energies is local and may harbor some features associated with relatively recent supernova (SN) activity in the solar neighborhood. Our analysis of the new AMS-02 results, together with Voyager 1 and ACE-CRIS data, reveals an unexpected bump in the iron spectrum and in the Fe/He, Fe/O, and Fe/Si ratios at 1–2 GV, while a similar feature in the spectra of He, O, and Si and in their ratios is absent, hinting at a local source of low-energy CRs. The found excess extends the recent discoveries of radioactive 60Fe deposits in terrestrial and lunar samples and in CRs. We provide an updated local interstellar spectrum (LIS) of iron in the energy range from 1 MeV nucleon−1 to ∼10 TeV nucleon−1. Our calculations employ the GalProp–HelMod framework, which has proved to be a reliable tool in deriving the LIS of CR , e −, and nuclei Z $łe$ 28.
URL, DOI BibTeX@article{2021ApJ_Fe, doi = "10.3847/1538-4357/abf11c", url = "https://arxiv.org/abs/2101.12735", year = 2021, month = "may", publisher = "American Astronomical Society", volume = 913, number = 1, pages = 5, author = "{Boschini}, M.J. and {Della Torre}, S. and {Gervasi}, M. and {Grandi}, D. and J{\'{o}}hannesson, G. and {La Vacca}, G. and {Masi}, N. and {Moskalenko}, I.V. and {Pensotti}, S. and {Porter}, T.A. and {Quadrani}, L. and {Rancoita}, P.G. and {Rozza}, D. and {Tacconi}, M.", title = "The Discovery of a Low-energy Excess in Cosmic-Ray Iron: Evidence of the Past Supernova Activity in the Local Bubble", journal = "The Astrophysical Journal", abstract = "Since its launch, the Alpha Magnetic Spectrometer—02 (AMS-02) has delivered outstanding quality measurements of the spectra of cosmic-ray (CR) species (p, e ±, and nuclei, 1H–8O, 10Ne, 12Mg, 14Si) which resulted in a number of breakthroughs. One of the latest long-awaited surprises is the spectrum of 26Fe just published by AMS-02. Because of the large fragmentation cross section and large ionization energy losses, most of CR iron at low energies is local and may harbor some features associated with relatively recent supernova (SN) activity in the solar neighborhood. Our analysis of the new AMS-02 results, together with Voyager 1 and ACE-CRIS data, reveals an unexpected bump in the iron spectrum and in the Fe/He, Fe/O, and Fe/Si ratios at 1–2 GV, while a similar feature in the spectra of He, O, and Si and in their ratios is absent, hinting at a local source of low-energy CRs. The found excess extends the recent discoveries of radioactive 60Fe deposits in terrestrial and lunar samples and in CRs. We provide an updated local interstellar spectrum (LIS) of iron in the energy range from 1 MeV nucleon−1 to ∼10 TeV nucleon−1. Our calculations employ the GalProp–HelMod framework, which has proved to be a reliable tool in deriving the LIS of CR , e −, and nuclei Z $\le$ 28.", hmwp = "AllP,LIS", aname = "BoschiniEtAl2021" }M J Boschini, S Della Torre, M Gervasi, D Grandi, G Jóhannesson, G La Vacca, N Masi, I V Moskalenko, S Pensotti, T A Porter, L Quadrani, P G Rancoita, D Rozza and M Tacconi.
Inference of the Local Interstellar Spectra of Cosmic-Ray Nuclei Z < 28 with the GalProp-HelMod Framework.
Astrophys. J. Supplement 250(2):27, September 2020.
Abstract Composition and spectra of Galactic cosmic rays (CRs) are vital for studies of high-energy processes in a variety of environments and on different scales, for interpretation of γ-ray and microwave observations, for disentangling possible signatures of new phenomena, and for understanding of our local Galactic neighborhood. Since its launch, AMS-02 has delivered outstanding-quality measurements of the spectra of , , and nuclei: 1H-8O, 10Ne, 12Mg, 14Si. These measurements resulted in a number of breakthroughs; however, spectra of heavier nuclei and especially low-abundance nuclei are not expected until later in the mission. Meanwhile, a comparison of published AMS-02 results with earlier data from HEAO-3-C2 indicates that HEAO-3-C2 data may be affected by undocumented systematic errors. Utilizing such data to compensate for the lack of AMS-02 measurements could result in significant errors. In this paper we show that a fraction of HEAO-3-C2 data match available AMS-02 measurements quite well and can be used together with Voyager 1 and ACE-CRIS data to make predictions for the local interstellar spectra (LIS) of nuclei that are not yet released by AMS-02. We are also updating our already-published LIS to provide a complete set from 1H-28Ni in the energy range from 1 MeV nucleon-1 to ∼100-500 TeV nucleon-1, thus covering 8-9 orders of magnitude in energy. Our calculations employ the GalProp-HelMod framework, which has proved to be a reliable tool in deriving the LIS of CR , e -, and nuclei 1H-8O.
URL, DOI BibTeX@article{2020ApJS_Z28, doi = "10.3847/1538-4365/aba901", url = "https://arxiv.org/abs/2006.01337", year = 2020, month = "sep", publisher = "American Astronomical Society", volume = 250, number = 2, pages = 27, author = "{Boschini}, M.J. and {Della Torre}, S. and {Gervasi}, M. and {Grandi}, D. and J{\'{o}}hannesson, G. and {La Vacca}, G. and {Masi}, N. and {Moskalenko}, I.V. and {Pensotti}, S. and {Porter}, T.A. and {Quadrani}, L. and {Rancoita}, P.G. and {Rozza}, D. and {Tacconi}, M.", title = "Inference of the Local Interstellar Spectra of Cosmic-Ray Nuclei Z < 28 with the {GalProp}-{HelMod} Framework", journal = "Astrophys. J. Supplement", abstract = "Composition and spectra of Galactic cosmic rays (CRs) are vital for studies of high-energy processes in a variety of environments and on different scales, for interpretation of γ-ray and microwave observations, for disentangling possible signatures of new phenomena, and for understanding of our local Galactic neighborhood. Since its launch, AMS-02 has delivered outstanding-quality measurements of the spectra of , , and nuclei: 1H-8O, 10Ne, 12Mg, 14Si. These measurements resulted in a number of breakthroughs; however, spectra of heavier nuclei and especially low-abundance nuclei are not expected until later in the mission. Meanwhile, a comparison of published AMS-02 results with earlier data from HEAO-3-C2 indicates that HEAO-3-C2 data may be affected by undocumented systematic errors. Utilizing such data to compensate for the lack of AMS-02 measurements could result in significant errors. In this paper we show that a fraction of HEAO-3-C2 data match available AMS-02 measurements quite well and can be used together with Voyager 1 and ACE-CRIS data to make predictions for the local interstellar spectra (LIS) of nuclei that are not yet released by AMS-02. We are also updating our already-published LIS to provide a complete set from 1H-28Ni in the energy range from 1 MeV nucleon-1 to ∼100-500 TeV nucleon-1, thus covering 8-9 orders of magnitude in energy. Our calculations employ the GalProp-HelMod framework, which has proved to be a reliable tool in deriving the LIS of CR , e -, and nuclei 1H-8O." }M J Boschini, S Della Torre, M Gervasi, D Grandi, G Jóhannesson, G La Vacca, N Masi, I V Moskalenko, S Pensotti, T A Porter, L Quadrani, P G Rancoita, D Rozza and M Tacconi.
Deciphering the Local Interstellar Spectra of Secondary Nuclei with the Galprop/Helmod Framework and a Hint for Primary Lithium in Cosmic Rays.
Astrophys. J. 889(2):167, 2020.
Abstract Local interstellar spectra (LIS) of secondary cosmic ray (CR) nuclei, lithium, beryllium, boron, and partially secondary nitrogen, are derived in the rigidity range from 10 MV to ~200 TV using the most recent experimental results combined with the state-of-the-art models for CR propagation in the Galaxy and in the heliosphere. The lithium spectrum appears somewhat flatter at high energies compared to other secondary species that may imply a primary lithium component. Two propagation packages, GALPROP and HelMod, are combined to provide a single framework that is run to reproduce direct measurements of CR species at different modulation levels, and at both polarities of the solar magnetic field. An iterative maximum-likelihood method is developed that uses GALPROP-predicted LIS as input to HelMod, which provides the modulated spectra for specific time periods of the selected experiments for the model-data comparison. The proposed LIS accommodate the low-energy interstellar spectra measured by Voyager 1, HEAO-3, and ACE/CRIS as well as the high-energy observations by PAMELA, AMS-02, and earlier experiments that are made deep in the heliosphere. The interstellar and heliospheric propagation parameters derived in this study are consistent with our earlier results for propagation of CR protons, helium, carbon, oxygen, antiprotons, and electrons.
URL, DOI BibTeX@article{2019ApJ_sec, author = "{Boschini}, M.J. and {Della Torre}, S. and {Gervasi}, M. and {Grandi}, D. and J{\'{o}}hannesson, G. and {La Vacca}, G. and {Masi}, N. and {Moskalenko}, I.V. and {Pensotti}, S. and {Porter}, T.A. and {Quadrani}, L. and {Rancoita}, P.G. and {Rozza}, D. and {Tacconi}, M.", title = "Deciphering the Local Interstellar Spectra of Secondary Nuclei with the Galprop/Helmod Framework and a Hint for Primary Lithium in Cosmic Rays", journal = "Astrophys. J.", year = 2020, month = "", volume = 889, number = 2, pages = 167, doi = "10.3847/1538-4357/ab64f1", url = "https://arxiv.org/abs/1911.03108", abstract = "Local interstellar spectra (LIS) of secondary cosmic ray (CR) nuclei, lithium, beryllium, boron, and partially secondary nitrogen, are derived in the rigidity range from 10 MV to ~200 TV using the most recent experimental results combined with the state-of-the-art models for CR propagation in the Galaxy and in the heliosphere. The lithium spectrum appears somewhat flatter at high energies compared to other secondary species that may imply a primary lithium component. Two propagation packages, GALPROP and HelMod, are combined to provide a single framework that is run to reproduce direct measurements of CR species at different modulation levels, and at both polarities of the solar magnetic field. An iterative maximum-likelihood method is developed that uses GALPROP-predicted LIS as input to HelMod, which provides the modulated spectra for specific time periods of the selected experiments for the model-data comparison. The proposed LIS accommodate the low-energy interstellar spectra measured by Voyager 1, HEAO-3, and ACE/CRIS as well as the high-energy observations by PAMELA, AMS-02, and earlier experiments that are made deep in the heliosphere. The interstellar and heliospheric propagation parameters derived in this study are consistent with our earlier results for propagation of CR protons, helium, carbon, oxygen, antiprotons, and electrons." }M J Boschini, S Della Torre, M Gervasi, G La Vacca and P G Rancoita.
The HelMod model in the works for inner and outer heliosphere: From AMS to Voyager probes observations.
Advances in Space Research 64(12):2459 - 2476, 2019.
Abstract HelMod is a Monte Carlo code developed to describe the transport of Galactic Cosmic Rays (GCRs) through the heliosphere from the interstellar space to the Earth. In the current HelMod version 4 the modulation process, based on Parker’s equation, is applied to the propagation of GCRs in the inner and outer heliosphere, i.e., including the heliosheath. HelMod was proved to reproduce protons, nuclei and electrons cosmic rays spectra observed during solar cycles 23-24 by several detectors, for instance, PAMELA, BESS and AMS-02. In particular, the unprecedented accuracy of AMS-02 observations allowed one a better tuning of the description regarding the solar modulation mechanisms implemented in HelMod. In addition, HelMod demonstrated to be capable of reproducing the fluxes observed by the Voyager probes in the inner and outer regions of heliosphere up to its border.
URL, DOI BibTeX@article{BOSCHINI20192459, title = "The HelMod model in the works for inner and outer heliosphere: From AMS to Voyager probes observations", journal = "Advances in Space Research", volume = 64, number = 12, pages = "2459 - 2476", year = 2019, issn = "0273-1177", doi = "10.1016/j.asr.2019.04.007", url = "https://arxiv.org/abs/1903.07501", author = "Boschini, M.J. and {Della Torre}, S. and Gervasi, M. and {La Vacca},G. and Rancoita, P.G.", keywords = "Solar modulation, Interplanetary space, Cosmic rays propagation, Termination Shock, Heliosphere", abstract = "HelMod is a Monte Carlo code developed to describe the transport of Galactic Cosmic Rays (GCRs) through the heliosphere from the interstellar space to the Earth. In the current HelMod version 4 the modulation process, based on Parker’s equation, is applied to the propagation of GCRs in the inner and outer heliosphere, i.e., including the heliosheath. HelMod was proved to reproduce protons, nuclei and electrons cosmic rays spectra observed during solar cycles 23-24 by several detectors, for instance, PAMELA, BESS and AMS-02. In particular, the unprecedented accuracy of AMS-02 observations allowed one a better tuning of the description regarding the solar modulation mechanisms implemented in HelMod. In addition, HelMod demonstrated to be capable of reproducing the fluxes observed by the Voyager probes in the inner and outer regions of heliosphere up to its border." }M J Boschini, Della S Torre, M Gervasi, D Grandi, G Jóhannesson, La G Vacca, N Masi, I V Moskalenko, S Pensotti, T A Porter, L Quadrani, P G Rancoita, D Rozza and M Tacconi.
Deciphering the Local Interstellar Spectra of Primary Cosmic-Ray Species with HelMod.
Astrophys. J. 858(1):61, 2018.
Abstract Local interstellar spectra (LIS) of primary cosmic ray (CR) nuclei, such as helium, oxygen, and mostly primary carbon are derived for the rigidity range from 10 MV to ∼200 TV using the most recent experimental results combined with the state-of-the-art models for CR propagation in the Galaxy and in the heliosphere. Two propagation packages, GALPROP and HelMod , are combined into a single framework that is used to reproduce direct measurements of CR species at different modulation levels, and at both polarities of the solar magnetic field. The developed iterative maximum-likelihood method uses GALPROP-predicted LIS as input to HelMod , which provides the modulated spectra for specific time periods of the selected experiments for model-data comparison. The interstellar and heliospheric propagation parameters derived in this study are consistent with our prior analyses using the same methodology for propagation of CR protons, helium, antiprotons, and electrons. The resulting LIS accommodate a variety of measurements made in the local interstellar space ( Voyager 1) and deep inside the heliosphere at low ( ACE /CRIS, HEAO- 3) and high energies ( PAMELA , AMS- 02).
URL, DOI BibTeX@article{2018ApJCO, author = "M. J. Boschini and S. Della Torre and M. Gervasi and D. Grandi and G. Jóhannesson and G. La Vacca and N. Masi and I. V. Moskalenko and S. Pensotti and T. A. Porter and L. Quadrani and P. G. Rancoita and D. Rozza and M. Tacconi", title = "Deciphering the Local Interstellar Spectra of Primary Cosmic-Ray Species with HelMod", journal = "Astrophys. J.", volume = 858, number = 1, pages = 61, url = "https://arxiv.org/abs/1804.06956", doi = "10.3847/1538-4357/aabc54", year = 2018, abstract = "Local interstellar spectra (LIS) of primary cosmic ray (CR) nuclei, such as helium, oxygen, and mostly primary carbon are derived for the rigidity range from 10 MV to ∼200 TV using the most recent experimental results combined with the state-of-the-art models for CR propagation in the Galaxy and in the heliosphere. Two propagation packages, GALPROP and HelMod , are combined into a single framework that is used to reproduce direct measurements of CR species at different modulation levels, and at both polarities of the solar magnetic field. The developed iterative maximum-likelihood method uses GALPROP-predicted LIS as input to HelMod , which provides the modulated spectra for specific time periods of the selected experiments for model-data comparison. The interstellar and heliospheric propagation parameters derived in this study are consistent with our prior analyses using the same methodology for propagation of CR protons, helium, antiprotons, and electrons. The resulting LIS accommodate a variety of measurements made in the local interstellar space ( Voyager 1) and deep inside the heliosphere at low ( ACE /CRIS, HEAO- 3) and high energies ( PAMELA , AMS- 02)." }M J Boschini, S Della Torre, M Gervasi, D Grandi, G Jóhannesson, G La Vacca, N Masi, I V Moskalenko, S Pensotti, T A Porter, L Quadrani, P G Rancoita, D Rozza and M Tacconi.
HELMOD In The Works: From Direct Observations To The Local Interstellar Spectrum Of Cosmic-Ray Electrons.
Astrophys. J. 854(2):94, 2018.
Abstract The local interstellar spectrum (LIS) of cosmic-ray (CR) electrons for the energy range 1 MeV to 1 TeV is derived using the most recent experimental results combined with the state-of-the-art models for CR propagation in the Galaxy and in the heliosphere. Two propagation packages, GALPROP and HelMod, are combined to provide a single framework that is run to reproduce direct measurements of CR species at different modulation levels, and at both polarities of the solar magnetic field. An iterative maximum-likelihood method is developed that uses GALPROP-predicted LIS as input to HelMod, which provides the modulated spectra for specific time periods of the selected experiments for model-data comparison. The optimized HelMod parameters are then used to adjust GALPROP parameters to predict a refined LIS with the procedure repeated subject to a convergence criterion. The parameter optimization uses an extensive data set of proton spectra from 1997-2015. The proposed CR electron LIS accommodates both the low-energy interstellar spectra measured by Voyager 1 as well as the high-energy observations by PAMELA and AMS-02 that are made deep in the heliosphere; it also accounts for Ulysses counting rate features measured out of the ecliptic plane. The interstellar and heliospheric propagation parameters derived in this study agree well with our earlier results for CR protons, helium nuclei, and anti-protons propagation and LIS obtained in the same framework.
URL, DOI BibTeX@article{2018ApJElectron, author = "{Boschini}, M. J. and {Della Torre}, S. and {Gervasi}, M. and {Grandi}, D. and J{\'o}hannesson, G. and {La Vacca}, G. and {Masi}, N. and {Moskalenko}, I. V. and {Pensotti}, S. and {Porter}, T. A. and {Quadrani}, L. and {Rancoita}, P. G. and {Rozza}, D. and {Tacconi}, M.", title = "HELMOD In The Works: From Direct Observations To The Local Interstellar Spectrum Of Cosmic-Ray Electrons", journal = "Astrophys. J.", year = 2018, month = "", volume = 854, number = 2, pages = 94, doi = "10.3847/1538-4357/aaa75e", url = "https://arxiv.org/abs/1704.06337", abstract = "The local interstellar spectrum (LIS) of cosmic-ray (CR) electrons for the energy range 1 MeV to 1 TeV is derived using the most recent experimental results combined with the state-of-the-art models for CR propagation in the Galaxy and in the heliosphere. Two propagation packages, GALPROP and HelMod, are combined to provide a single framework that is run to reproduce direct measurements of CR species at different modulation levels, and at both polarities of the solar magnetic field. An iterative maximum-likelihood method is developed that uses GALPROP-predicted LIS as input to HelMod, which provides the modulated spectra for specific time periods of the selected experiments for model-data comparison. The optimized HelMod parameters are then used to adjust GALPROP parameters to predict a refined LIS with the procedure repeated subject to a convergence criterion. The parameter optimization uses an extensive data set of proton spectra from 1997-2015. The proposed CR electron LIS accommodates both the low-energy interstellar spectra measured by Voyager 1 as well as the high-energy observations by PAMELA and AMS-02 that are made deep in the heliosphere; it also accounts for Ulysses counting rate features measured out of the ecliptic plane. The interstellar and heliospheric propagation parameters derived in this study agree well with our earlier results for CR protons, helium nuclei, and anti-protons propagation and LIS obtained in the same framework." }M J Boschini, S Della Torre, M Gervasi, G La Vacca and P G Rancoita.
Propagation of Cosmic Rays in Heliosphere: the HelMod Model.
Adv. Space Res. 62(10):2859 - 2879, 2018.
Abstract The heliospheric modulation model HelMod is a two dimensional treatment dealing with the helio-colatitude and radial distance from Sun and is employed to solve the transport-equation for the GCR propagation through the heliosphere down to Earth. This work presents the current version 3 of the HelMod model and reviews how main processes involved in GCR propagation were implemented. The treatment includes the so-called particle drift effects – e.g., those resulting, for instance, from the extension of the neutral current sheet inside the heliosphere and from the curvature and gradient of the IMF –, which affect the transport of particles entering the solar cavity as a function of their charge sign. The HelMod model is capable to provide modulated spectra which well agree within the experimental errors with those measured by AMS-01, BESS, PAMELA and AMS-02 during the solar cycles 23 and 24. Furthermore, the counting rate measured by Ulysses at +/- 80degree of solar latitude and 1 to 5 AU was also found in agreement with that expected by HelMod code version 3.
URL, DOI BibTeX@article{DellaTorre2017, author = "{Boschini}, M.J. and {Della Torre}, S. and {Gervasi}, M. and {La Vacca}, G. and {Rancoita}, P.G.", title = "{Propagation of Cosmic Rays in Heliosphere: the HelMod Model}", journal = "Adv. Space Res.", volume = 62, number = 10, pages = "2859 - 2879", year = 2018, note = "Origins of Cosmic Rays", issn = "0273-1177", url = "https://arxiv.org/abs/1704.03733", doi = "10.1016/j.asr.2017.04.017", abstract = "The heliospheric modulation model HelMod is a two dimensional treatment dealing with the helio-colatitude and radial distance from Sun and is employed to solve the transport-equation for the GCR propagation through the heliosphere down to Earth. This work presents the current version 3 of the HelMod model and reviews how main processes involved in GCR propagation were implemented. The treatment includes the so-called particle drift effects -- e.g., those resulting, for instance, from the extension of the neutral current sheet inside the heliosphere and from the curvature and gradient of the IMF --, which affect the transport of particles entering the solar cavity as a function of their charge sign. The HelMod model is capable to provide modulated spectra which well agree within the experimental errors with those measured by AMS-01, BESS, PAMELA and AMS-02 during the solar cycles 23 and 24. Furthermore, the counting rate measured by Ulysses at +/- 80degree of solar latitude and 1 to 5 AU was also found in agreement with that expected by HelMod code version 3." }M J Boschini, S Della Torre, M Gervasi, D Grandi, G Johannesson, M Kachelriess, G La Vacca, N Masi, I V Moskalenko, E Orlando, S ~S Ostapchenko, S Pensotti, T A Porter, L Quadrani and P G Rancoita.
Solution of Heliospheric Propagation: Unveiling the Local Interstellar Spectra of Cosmic Ray Species.
Astrophys. J. 840(2):115, 2017.
Abstract Local interstellar spectra (LIS) for protons, helium and antiprotons are built using the most recent experimental results combined with the 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 self-consistent 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 HelMod parameters optimization is performed at this stage and looped back to adjust the LIS using the new GALPROP run. The parameters were tuned with the 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; it also accounts for Ulysses counting rate features measured out of the ecliptic plane. The found solution is in a good agreement with proton, helium, and antiproton data by AMS-02, BESS, and PAMELA in the whole energy range
URL, DOI BibTeX@article{BoskiniEtAl2017_LIS, author = "{Boschini}, M.J. and {Della Torre}, S. and {Gervasi}, M. and {Grandi}, D. and Johannesson, G. and Kachelriess, M. and {La Vacca}, G. and Masi, N. and Moskalenko, I.V. and Orlando, E. and Ostapchenko, S.~S. and Pensotti, S. and Porter, T. A. and Quadrani, L. and {Rancoita}, P.G.", title = "Solution of Heliospheric Propagation: Unveiling the Local Interstellar Spectra of Cosmic Ray Species", journal = "Astrophys. J.", year = 2017, number = 2, volume = 840, pages = 115, url = "https://arxiv.org/abs/1704.06337", doi = "10.3847/1538-4357/aa6e4f", abstract = "Local interstellar spectra (LIS) for protons, helium and antiprotons are built using the most recent experimental results combined with the 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 self-consistent 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 HelMod parameters optimization is performed at this stage and looped back to adjust the LIS using the new GALPROP run. The parameters were tuned with the 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; it also accounts for Ulysses counting rate features measured out of the ecliptic plane. The found solution is in a good agreement with proton, helium, and antiproton data by AMS-02, BESS, and PAMELA in the whole energy range" }P Bobik, M J Boschini, S Della Torre, M Gervasi, D Grandi, G La Vacca, S Pensotti, M Putis, P G Rancoita, D Rozza, M Tacconi and M Zannoni.
On the forward-backward-in-time approach for Monte Carlo solution of Parker's transport equation: One-dimensional case.
Journal of Geophysical Research: Space Physics 121(5):3920–3930, 2016.
Abstract 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.
URL, DOI BibTeX@article{JGRA:JGRA52618, author = "Bobik, P. and Boschini, M. J. and Della Torre, S. and Gervasi, M. and Grandi, D. and La Vacca, G. and Pensotti, S. and Putis, M. and Rancoita, P. G. and Rozza, D. and Tacconi, M. and Zannoni, M.", title = "On the forward-backward-in-time approach for Monte Carlo solution of Parker's transport equation: One-dimensional case", journal = "Journal of Geophysical Research: Space Physics", volume = 121, number = 5, issn = "2169-9402", url = "http://dx.doi.org/10.1002/2015JA022237", doi = "10.1002/2015JA022237", pages = "3920--3930", keywords = "Numerical algorithms, Software tools and services, Cosmic rays, General or miscellaneous, Mathematical and numerical techniques, Monte Carlo, cosmic rays propagation, heliosphere", year = 2016, note = "2015JA022237", abstract = "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." }P Bobik, G Boella, M J Boschini, C Consolandi, S Della Torre, M Gervasi, D Grandi, K Kudela, S Pensotti, P G Rancoita, D Rozza and M Tacconi.
Latitudinal Dependence of Cosmic Rays Modulation at 1 AU and Interplanetary Magnetic Field Polar Correction.
Advances in Astronomy 2013, 2013.
Abstract The cosmic rays differential intensity inside the heliosphere, for energy below 30 GeV/nuc, depends on solar activity and interplanetary magnetic field polarity. is variation, termed solar modulation, is described using a 2D (radius and colatitude) Monte Carlo approach for solving the Parker transport equation that includes diffusion, convection, magnetic drift, and adiabatic energy loss. Since the whole transport is strongly related to the interplanetary magnetic field (IMF) structure, a better understanding of his description is needed in order to reproduce the cosmic rays intensity at the Earth, as well as outside the ecliptic plane. In this work an interplanetary magnetic field model including the standard description on ecliptic region and a polar correction is presented. this treatment of the IMF, implemented in the HelMod Monte Carlo code (version 2.0), was used to determine the effects on the differential intensity of Proton at 1 AU and allowed one to investigate how latitudinal gradients of proton intensities, observed in the inner heliosphere with the Ulysses spacecra during 1995, can be affected by the modification of the IMF in the polar regions.
URL, DOI BibTeX@article{DellaTorre2013AdvAstro, author = "{Bobik}, P. and {Boella}, G. and {Boschini}, M.J.. and {Consolandi}, C. and {Della Torre}, S. and {Gervasi}, M. and {Grandi}, D. and {Kudela}, K. and {Pensotti}, S. and {Rancoita}, P.G. and {Rozza}, D. and {Tacconi}, M.", title = "{Latitudinal Dependence of Cosmic Rays Modulation at 1 AU and Interplanetary Magnetic Field Polar Correction}", journal = "Advances in Astronomy", archiveprefix = "arXiv", eprint = "1212.1559", primaryclass = "astro-ph.SR", year = 2013, volume = 2013, eid = 793072, doi = "10.1155/2013/793072", adsurl = "http://adsabs.harvard.edu/abs/2013AdAst2013E...1B", adsnote = "Provided by the SAO/NASA Astrophysics Data System", abstract = "The cosmic rays differential intensity inside the heliosphere, for energy below 30 GeV/nuc, depends on solar activity and interplanetary magnetic field polarity. is variation, termed solar modulation, is described using a 2D (radius and colatitude) Monte Carlo approach for solving the Parker transport equation that includes diffusion, convection, magnetic drift, and adiabatic energy loss. Since the whole transport is strongly related to the interplanetary magnetic field (IMF) structure, a better understanding of his description is needed in order to reproduce the cosmic rays intensity at the Earth, as well as outside the ecliptic plane. In this work an interplanetary magnetic field model including the standard description on ecliptic region and a polar correction is presented. this treatment of the IMF, implemented in the HelMod Monte Carlo code (version 2.0), was used to determine the effects on the differential intensity of Proton at 1 AU and allowed one to investigate how latitudinal gradients of proton intensities, observed in the inner heliosphere with the Ulysses spacecra during 1995, can be affected by the modification of the IMF in the polar regions.", url = "https://arxiv.org/abs/1212.1559" }S Della Torre, P Bobik, M J Boschini, C Consolandi, M Gervasi, D Grandi, K Kudela, S Pensotti, P G Rancoita, D Rozza and M Tacconi.
Effects of solar modulation on the cosmic ray positron fraction.
Adv. Space Res. 49:1587-1592, 2012.
Abstract We implemented a 2D Monte Carlo model to simulate the solar modulation of galactic cosmic rays. The model is based on the Par- ker’s transport equation which contains diffusion, convection, particle drift and energy loss. Following the evolution in time of the solar activity, we are able to modulate a local interstellar spectrum (LIS), that we assumed isotropic beyond the termination shock, down to the Earth position inside the heliosphere. In this work we focused our attention to the cosmic ray positron fraction at energy below ~10 GeV, showing how the particle drift processes could explain different results for AMS-01 and PAMELA. We compare our modu- lated spectra with observations at Earth, and then make a prediction of the cosmic ray positron fraction for the AMS-02 experiment.
DOI BibTeX@article{DellaTorre2012, author = "{Della Torre}, S. and {Bobik}, P. and {Boschini}, M.J.. and {Consolandi}, C. and {Gervasi}, M. and {Grandi}, D. and {Kudela}, K. and {Pensotti}, S. and {Rancoita}, P.G. and {Rozza}, D. and {Tacconi}, M.", title = "{Effects of solar modulation on the cosmic ray positron fraction}", journal = "Adv. Space Res.", year = 2012, month = "", volume = 49, pages = "1587-1592", doi = "10.1016/j.asr.2012.02.017", abstract = "We implemented a 2D Monte Carlo model to simulate the solar modulation of galactic cosmic rays. The model is based on the Par- ker’s transport equation which contains diffusion, convection, particle drift and energy loss. Following the evolution in time of the solar activity, we are able to modulate a local interstellar spectrum (LIS), that we assumed isotropic beyond the termination shock, down to the Earth position inside the heliosphere. In this work we focused our attention to the cosmic ray positron fraction at energy below ~10 GeV, showing how the particle drift processes could explain different results for AMS-01 and PAMELA. We compare our modu- lated spectra with observations at Earth, and then make a prediction of the cosmic ray positron fraction for the AMS-02 experiment.", adsurl = "http://adsabs.harvard.edu/abs/2012AdSpR..49.1587D", adsnote = "Provided by the SAO/NASA Astrophysics Data System" }P Bobik, G Boella, M J Boschini, C Consolandi, S Della Torre, M Gervasi, D Grandi, K Kudela, S Pensotti, P G Rancoita and M Tacconi.
Systematic Investigation of Solar Modulation of Galactic Protons for Solar Cycle 23 Using a Monte Carlo Approach with Particle Drift Effects and Latitudinal Dependence.
Astrophys. J. 745:132, 2012.
Abstract A propagation model of galactic cosmic protons through the heliosphere was implemented using a two-dimensional Monte Carlo approach to determine the differential intensities of protons during solar cycle 23. The model includes the effects due to the variation of solar activity during the propagation of cosmic rays from the boundary of the heliopause down to Earth’s position. Drift effects are also accounted for. The simulated spectra were found to be in agreement with those obtained from experimental observations carried out by the BESS, AMS, and PAMELA collaborations. In addition, the modulated spectrum determined with the present code for the year 1995 exhibits the latitudinal gradient and equatorial southward offset minimum found by the Ulysses fast scan in 1995.
URL, DOI BibTeX@article{Bobik2011ApJ, author = "{Bobik}, P. and {Boella}, G. and {Boschini}, M.J. and {Consolandi}, C. and {Della Torre}, S. and {Gervasi}, M. and {Grandi}, D. and {Kudela}, K. and {Pensotti}, S. and {Rancoita}, P.G. and {Tacconi}, M.", title = "Systematic Investigation of Solar Modulation of Galactic Protons for Solar Cycle 23 Using a Monte Carlo Approach with Particle Drift Effects and Latitudinal Dependence", journal = "Astrophys. J.", archiveprefix = "arXiv", eprint = "1110.4315", primaryclass = "astro-ph.SR", abstract = "A propagation model of galactic cosmic protons through the heliosphere was implemented using a two-dimensional Monte Carlo approach to determine the differential intensities of protons during solar cycle 23. The model includes the effects due to the variation of solar activity during the propagation of cosmic rays from the boundary of the heliopause down to Earth’s position. Drift effects are also accounted for. The simulated spectra were found to be in agreement with those obtained from experimental observations carried out by the BESS, AMS, and PAMELA collaborations. In addition, the modulated spectrum determined with the present code for the year 1995 exhibits the latitudinal gradient and equatorial southward offset minimum found by the Ulysses fast scan in 1995.", keywords = "cosmic rays, solar-terrestrial relations, solar wind, Sun: heliosphere", year = 2012, month = "", volume = 745, eid = 132, pages = 132, doi = "10.1088/0004-637X/745/2/132", adsurl = "http://adsabs.harvard.edu/abs/2012ApJ...745..132B", adsnote = "Provided by the SAO/NASA Astrophysics Data System", url = "https://arxiv.org/abs/1110.4315" }P Bobik, M J Boschini, C Consolandi, S Della Torre, M Gervasi, D Grandi, K Kudela, S Pensotti and P G Rancoita.
Antiproton modulation in the Heliosphere and AMS-02 antiproton over proton ratio prediction.
Astrophys. Space Sci. Trans. 7(3):245–249, 2011.
Abstract We implemented a quasi time-dependent 2D stochastic model of solar modulation describing the transport of cosmic rays (CR) in the heliosphere. Our code can modulate the Local Interstellar Spectrum (LIS) of a generic charged particle (light cosmic ions and electrons), calculating the spectrum at 1AU. Several measurements of CR antiparticles have been performed. Here we focused our attention on the CR antiproton component and the antiproton over proton ratio. We show that our model, using the same heliospheric parameters for both particles, fit the observed anti-p/p ratio. We show a good agreement with BESS-97 and PAMELA data and make a prediction for the AMS-02 experiment.
URL, DOI BibTeX@article{AstraArticle2011, author = "{Bobik}, P. and {Boschini}, M.J.. and {Consolandi}, C. and {Della Torre}, S. and {Gervasi}, M. and {Grandi}, D. and {Kudela}, K. and {Pensotti}, S. and {Rancoita}, P.G.", title = "Antiproton modulation in the Heliosphere and AMS-02 antiproton over proton ratio prediction", journal = "Astrophys. Space Sci. Trans.", year = 2011, volume = 7, pages = "245--249", number = 3, abstract = "We implemented a quasi time-dependent 2D stochastic model of solar modulation describing the transport of cosmic rays (CR) in the heliosphere. Our code can modulate the Local Interstellar Spectrum (LIS) of a generic charged particle (light cosmic ions and electrons), calculating the spectrum at 1AU. Several measurements of CR antiparticles have been performed. Here we focused our attention on the CR antiproton component and the antiproton over proton ratio. We show that our model, using the same heliospheric parameters for both particles, fit the observed anti-p/p ratio. We show a good agreement with BESS-97 and PAMELA data and make a prediction for the AMS-02 experiment.", doi = "10.5194/astra-7-245-2011", file = "1102.0215:http\://arxiv.org/pdf/1102.0215:PDF", keywords = "Earth and Planetary Astrophysics (astro-ph.EP)", url = "http://arxiv.org/abs/1102.0215" }
Conference proceedings
M Boschini, S Della Torre, M Gervasi, D Grandi, G La Vacca, S Pensotti, P G Rancoita, D Rozza and M Tacconi.
The HelMod Monte Carlo Model for the Propagation of Cosmic Rays in Heliosphere.
Proceedings of the International Astronomical Union, Proceedings of IAU Symposium 335 - Space Weather of the Heliosphere: Processes and Forecasts, July 17-21, 2017, University of Exeter, UK 13(S335):276–279, 2017.
URL, DOI BibTeX@article{IAUS2017a, author = "Boschini, M. and Della Torre, S. and Gervasi, M. and Grandi, D. and {La Vacca}, G. and Pensotti, S. and Rancoita, P.G. and Rozza, D. and Tacconi, M.", title = "The HelMod Monte Carlo Model for the Propagation of Cosmic Rays in Heliosphere", volume = 13, doi = "10.1017/S1743921317007359", number = "S335", journal = "Proceedings of the International Astronomical Union, Proceedings of IAU Symposium 335 - Space Weather of the Heliosphere: Processes and Forecasts, July 17-21, 2017, University of Exeter, UK", publisher = "Cambridge University Press", year = 2017, pages = "276–279", url = "https://arxiv.org/abs/1708.04690" }S Della Torre, M Gervasi, D Grandi, G Johannesson, G La Vacca, N Masi, I V Moskalenko, E Orlando, T A Porter, L Quadrani, P G Rancoita and D Rozza.
From Observations near the Earth to the Local Interstellar Spectra.
In Proceedings of the 25th European Cosmic Rays Symposyum (ECRS2016) eConf C16-09-04.3, Septembers 4-9,2016 (Torino, Italy), arXiv: 1701.02363. 2016.
URL BibTeX@inproceedings{ECRS2016b, author = "Della Torre, S. and Gervasi, M. and Grandi, D. and Johannesson, G. and {La Vacca}, G. and Masi, N. and Moskalenko, I.V. and Orlando, E. and Porter, T.A. and Quadrani, L. and Rancoita, P.G. and Rozza, D.", title = "{From Observations near the Earth to the Local Interstellar Spectra}", year = 2016, booktitle = "Proceedings of the 25th European Cosmic Rays Symposyum (ECRS2016) eConf C16-09-04.3, Septembers 4-9,2016 (Torino, Italy), arXiv: 1701.02363", url = "https://arxiv.org/abs/1701.02363" }S Della Torre, M Gervasi, D Grandi, G Johannesson, G La Vacca, N Masi, I V Moskalenko, E Orlando, T A Porter, L Quadrani, P G Rancoita and D Rozza.
HelMod: a Comprehensive Treatment of the Cosmic Ray transport through the Heliosphere.
In Proceedings of the 25th European Cosmic Rays Symposyum (ECRS2016) eConf C16-09-04.3, Septembers 4-9,2016 (Torino, Italy), arXiv: 1612.08445. 2016.
URL BibTeX@inproceedings{ECRS2016, author = "Della Torre, S. and Gervasi, M. and Grandi, D. and Johannesson, G. and {La Vacca}, G. and Masi, N. and Moskalenko, I.V. and Orlando, E. and Porter, T.A. and Quadrani, L. and Rancoita, P.G. and Rozza, D.", title = "{HelMod: a Comprehensive Treatment of the Cosmic Ray transport through the Heliosphere}", year = 2016, booktitle = "Proceedings of the 25th European Cosmic Rays Symposyum (ECRS2016) eConf C16-09-04.3, Septembers 4-9,2016 (Torino, Italy), arXiv: 1612.08445", url = "https://arxiv.org/abs/1612.08445" }S Della Torre, P Bobik, M J Boschini, M Gervasi, D Grandi, G La Vacca, S Pensotti, M Putis, P G Rancoita, D Rozza, M Tacconi and M Zannoni.
Cosmic Rays Propagation with HelMod: Difference between forward-in-time and backward-in-time approaches.
In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), July 30 - August 6, 2015 (The Hague, The Netherlands). 2015.
URL BibTeX@inproceedings{DellaTorreICRC2015, author = "Della Torre, S. and Bobik, P and Boschini, M.J. and Gervasi, M. and Grandi, D and La Vacca, G. and Pensotti, S. and Putis, M. and Rancoita, P.G. and Rozza, D. and Tacconi, M. and Zannoni, M.", title = "{Cosmic Rays Propagation with HelMod: Difference between forward-in-time and backward-in-time approaches}", year = "2015 arXiv:1511.00541", booktitle = "Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), July 30 - August 6, 2015 (The Hague, The Netherlands)", url = "https://arxiv.org/abs/1511.00541" }P Bobik, G Boella, M J Boschini, S Della Torre, M Gervasi, D Grandi, G La Vacca, K Kudela, S Pensotti, P G Rancoita, D Rozza and M Tacconi.
Cosmic Ray Modulation studied with HelMod Monte Carlo tool and comparison with Ulysses Fast Scan Data during consecutive Solar Minimums.
In Proceedings of the 33rd International Cosmic Ray Conference (ICRC2013), July 2-9 2013 (Rio de Janeiro, Brazil), arXiv: 1307.5199. 2013, 1100.
URL BibTeX@inproceedings{ICRC13_DellaTorre, author = "{Bobik}, P. and {Boella}, G. and {Boschini}, M.J. and {Della Torre}, S. and {Gervasi}, M. and {Grandi}, D. and {La Vacca}, G. and {Kudela}, K. and {Pensotti}, S. and {Rancoita}, P.G. and {Rozza}, D. and {Tacconi}, M.", title = "Cosmic Ray Modulation studied with HelMod Monte Carlo tool and comparison with Ulysses Fast Scan Data during consecutive Solar Minimums", booktitle = "Proceedings of the 33rd International Cosmic Ray Conference (ICRC2013), July 2-9 2013 (Rio de Janeiro, Brazil), arXiv: 1307.5199", year = 2013, pages = 1100, series = "International Cosmic Ray Conference", journal = "arXiv: 1307.5199", archiveprefix = "arXiv", eprint = "1307.5199", slaccitation = "%%CITATION = ARXIV:1307.5199;%%", url = "https://arxiv.org/abs/1307.5199" }P Bobik, M J Boschini, C Consolandi, S Della Torre, M Gervasi and others.
GeoMag and HelMod webmodels version for magnetosphere and heliosphere transport of cosmic rays.
In Proceedings of the 33rd International Cosmic Ray Conference (ICRC2013), July 2-9 2013 (Rio de Janeiro, Brazil), arXiv: 1307.5196. 2013.
URL BibTeX@inproceedings{ICRC13_Bobik, author = "Bobik, P. and Boschini, M.J. and Consolandi, C. and Della Torre, S. and Gervasi, M. and others", title = "GeoMag and HelMod webmodels version for magnetosphere and heliosphere transport of cosmic rays", year = 2013, booktitle = "Proceedings of the 33rd International Cosmic Ray Conference (ICRC2013), July 2-9 2013 (Rio de Janeiro, Brazil), arXiv: 1307.5196", journal = "arXiv: 1307.5196", eprint = "1307.5196", archiveprefix = "arXiv", primaryclass = "astro-ph.IM", slaccitation = "%%CITATION = ARXIV:1307.5196;%%", url = "https://arxiv.org/abs/1307.5196" }P Bobik, M J Boschini, S Della Torre, M Gervasi, D Grandi, K Kudela, G La Vacca, M Mallamaci, S Pensotti, P G Rancoita, D Rozza and M Tacconi.
Solar Modulation along last solar minimum.
In S Giani and al. (eds.). Astroparticle, Particle, Space Physics, Radiation Interaction, Detectors and Medical Physics Applications: Volume 8. Proceedings of the 14th ICATPP Conference. Como, Italy, 23 – 27 September 2013. 2013, 177-181.
DOI BibTeX@inproceedings{2014ICATPP_DellaTorre, author = "{Bobik}, P. and {Boschini}, M.J. and {Della Torre}, S. and {Gervasi}, M. and {Grandi}, D. and {Kudela}, K. and {La Vacca}, G. and {Mallamaci}, M. and {Pensotti}, S. and {Rancoita}, P.G. and {Rozza}, D. and {Tacconi}, M.", title = "{Solar Modulation along last solar minimum}", booktitle = "Astroparticle, Particle, Space Physics, Radiation Interaction, Detectors and Medical Physics Applications: Volume 8. Proceedings of the 14th ICATPP Conference. Como, Italy, 23 – 27 September 2013", year = 2013, editor = "{Giani}, S. and {et al.}", month = "", pages = "177-181", doi = "10.1142/9789814603164_0027", adsurl = "http://adsabs.harvard.edu/abs/2014apsp.conf..177B", adsnote = "Provided by the SAO/NASA Astrophysics Data System" }P Bobik, M J Boschini, C Consolandi, Della S Torre, M Gervasi, D Grandi, K Kudela, F Noventa, S Pensotti, P G Rancoita and D Rozza.
HELIOSPHERE DIMENSION AND COSMIC RAY MODULATION.
In Astroparticle, Particle, Space Physics and Detectors for Physics Applications: Volume 7. Proceedings of the 13th ICATPP Conference. Villa Olmo, Como, Italy, 3 – 7 October 2011. 2011, 249-257.
URL, DOI BibTeX@inproceedings{ICATPP2011_DimHelio, author = "P. Bobik and M. J. Boschini and C. Consolandi and S. Della Torre and M. Gervasi and D. Grandi and K. Kudela and F. Noventa and S. Pensotti and P. G. Rancoita and D. Rozza", title = "HELIOSPHERE DIMENSION AND COSMIC RAY MODULATION", booktitle = "Astroparticle, Particle, Space Physics and Detectors for Physics Applications: Volume 7. Proceedings of the 13th ICATPP Conference. Villa Olmo, Como, Italy, 3 – 7 October 2011", pages = "249-257", doi = "10.1142/9789814405072_0037", url = "https://arxiv.org/abs/1112.5730", eprint = "http://www.worldscientific.com/doi/pdf/10.1142/9789814405072_0037", publisher = "WORLD SCIENTIFIC", year = 2011 }P Bobik, M J Boschini, C Consolandi, M Della Torre S. Gervasi, D Grandi, K Kudela, F Noventa, S Pensotti, P G Rancoita and D Rozza.
Cosmic Rays propagation in the Heliosphere.
In Astroparticle, Particle, Space Physics and Detectors for Physics Applications: Volume 7. Proceedings of the 13th ICATPP Conference. Villa Olmo, Como, Italy, 3 – 7 October 2011. 2011, 226-231.
URL, DOI BibTeX@inproceedings{ICATPP2011_Trasmission, author = "{Bobik}, P. and {Boschini}, M.J. and {Consolandi}, C. and {Della Torre}, S. {Gervasi}, M. and {Grandi}, D. and {Kudela}, K. and {Noventa}, F. and {Pensotti}, S. and {Rancoita}, P.G. and {Rozza}, D.", title = "Cosmic Rays propagation in the Heliosphere", booktitle = "Astroparticle, Particle, Space Physics and Detectors for Physics Applications: Volume 7. Proceedings of the 13th ICATPP Conference. Villa Olmo, Como, Italy, 3 – 7 October 2011", pages = "226-231", doi = "10.1142/9789814405072_0034", url = "http://www.worldscientific.com/doi/abs/10.1142/9789814405072_0034", eprint = "http://www.worldscientific.com/doi/pdf/10.1142/9789814405072_0034", publisher = "WORLD SCIENTIFIC", year = 2011 }P Bobik, G Boella, M ~J Boschini, C Consolandi, S Della Torre, M Gervasi, D Grandi, K Kudela, E Memola, S Pensotti, P ~G Rancoita and M Tacconi.
Proton Modulation in the Heliosphere for Different Solar Conditions and Prediction for AMS-02.
In S Giani, C Leroy and P ~G Rancoita (eds.). Astroparticle, Particle, Space Physics, Radiation Interaction, Detectors and Medical Physics Applications: Volume 6. Cosmic Rays for Particle and Astroparticle Physics. Proceedings of the 12th ICATPP Conference. Villa Olmo, Como, Italy, 7 – 8 October 2010. June 2010, 352-359 arXiv:1012.0938.
URL, DOI BibTeX@inproceedings{2011crpa.conf..352B, author = "{Bobik}, P. and {Boella}, G. and {Boschini}, M.~J. and {Consolandi}, C. and {Della Torre}, S. and {Gervasi}, M. and {Grandi}, D. and {Kudela}, K. and {Memola}, E. and {Pensotti}, S. and {Rancoita}, P.~G. and {Tacconi}, M.", title = "{Proton Modulation in the Heliosphere for Different Solar Conditions and Prediction for AMS-02}", keywords = "Heliosphere, Cosmic Rays, Solar Magnetic Field", booktitle = "Astroparticle, Particle, Space Physics, Radiation Interaction, Detectors and Medical Physics Applications: Volume 6. Cosmic Rays for Particle and Astroparticle Physics. Proceedings of the 12th ICATPP Conference. Villa Olmo, Como, Italy, 7 – 8 October 2010", year = 2010, archiveprefix = "arXiv", eprint = "1012.0938", primaryclass = "astro-ph.EP", editor = "{Giani}, S. and {Leroy}, C. and {Rancoita}, P.~G.", month = "jun", pages = "352-359 arXiv:1012.0938", url = "https://arxiv.org/abs/1012.0938", doi = "10.1142/9789814329033_0045", adsurl = "http://adsabs.harvard.edu/abs/2011crpa.conf..352B", adsnote = "Provided by the SAO/NASA Astrophysics Data System" }P Bobik, M J Boschini, C Consolandi, S Della Torre, M Gervasi, D Grandi, K Kudela, S Pensotti and P G Rancoita.
Electron and Positron solar modulation and prediction for AMS02.
In S Giani, C Leroy and P G Rancoita (eds.). Astroparticle, Particle, Space Physics, Radiation Interaction, Detectors and Medical Physics Applications: Volume 6. Cosmic Rays for Particle and Astroparticle Physics. Proceedings of the 12th ICATPP Conference. Villa Olmo, Como, Italy, 7 – 8 October 2010. June 2010, 337-342 arXiv:1011.4843.
URL, DOI BibTeX@inproceedings{ICATPP2010_Electron, author = "{Bobik}, P. and {Boschini}, M.J. and {Consolandi}, C. and {Della Torre}, S. and {Gervasi}, M. and {Grandi}, D. and {Kudela}, K. and {Pensotti}, S. and {Rancoita}, P.G.", title = "{Electron and Positron solar modulation and prediction for AMS02}", keywords = "cosmic rays, heliosphere, positron ratio, solar modulation", booktitle = "Astroparticle, Particle, Space Physics, Radiation Interaction, Detectors and Medical Physics Applications: Volume 6. Cosmic Rays for Particle and Astroparticle Physics. Proceedings of the 12th ICATPP Conference. Villa Olmo, Como, Italy, 7 – 8 October 2010", year = 2010, archiveprefix = "arXiv", eprint = "1011.4843", primaryclass = "astro-ph.SR", editor = "{Giani}, S. and {Leroy}, C. and {Rancoita}, P.G.", month = "jun", pages = "337-342 arXiv:1011.4843", doi = "10.1142/9789814329033_0043", url = "https://arxiv.org/abs/1011.4843", adsurl = "http://adsabs.harvard.edu/abs/2011crpa.conf..337B", adsnote = "Provided by the SAO/NASA Astrophysics Data System" }P Bobik, G Boella, M J Boschini, C Consolandi, Della S Torre, M Gervasi, D Grandi, M Elmo, K Kudela, E Memola, S Pensotti, P G Rancoita, D Rozza and M Tacconi.
ENERGY LOSS FOR ELECTRONS IN THE HELIOSPHERE AND LOCAL INTERSTELLAR SPECTRUM FOR SOLAR MODULATION.
In Astroparticle, Particle, Space Physics, Radiation Interaction, Detectors and Medical Physics Applications: Volume 6. Cosmic Rays for Particle and Astroparticle Physics. Proceedings of the 12th ICATPP Conference Villa Olmo, Como, Italy, 7 – 8 October 2010. 2010, 482-489.
URL, DOI BibTeX@inproceedings{mauroPoster2010, author = "P. Bobik and G. Boella and M.J. Boschini and C. Consolandi and S. Della Torre and M. Gervasi and D. Grandi and M. Elmo and K. Kudela and E. Memola and S. Pensotti and P.G. Rancoita and D. Rozza and M. Tacconi", title = "ENERGY LOSS FOR ELECTRONS IN THE HELIOSPHERE AND LOCAL INTERSTELLAR SPECTRUM FOR SOLAR MODULATION", booktitle = "Astroparticle, Particle, Space Physics, Radiation Interaction, Detectors and Medical Physics Applications: Volume 6. Cosmic Rays for Particle and Astroparticle Physics. Proceedings of the 12th ICATPP Conference Villa Olmo, Como, Italy, 7 – 8 October 2010", pages = "482-489", doi = "10.1142/9789814329033_0060", url = "http://www.worldscientific.com/doi/abs/10.1142/9789814329033_0060", eprint = "http://www.worldscientific.com/doi/pdf/10.1142/9789814329033_0060", publisher = "WORLD SCIENTIFIC", year = 2010 }P Bobik, M J Boschini, S Della Torre, M Gervasi, D Grandi, K Kudela, S Pensotti and P G Rancoita.
Proton and antiproton modulation in the heliosphere for different solar conditions and AMS-02 measurements prediction.
In C Leroy, P G Rancoita, M Barone, A Gaddi, L Price and R Ruchti (eds.). Astroparticle, Particle, Space Physics, Radiation Interaction, Detectors and Medical Physics Applications: Volume 6. Cosmic Rays for Particle and Astroparticle Physics. Proceedings of the 12th ICATPP Conference. Villa Olmo, Como, Italy, 7 – 8 October 2010. 2010, 360–368 arXiv:1012.3086.
URL, DOI BibTeX@inproceedings{DavArticle2010, author = "{Bobik}, P. and {Boschini}, M.J. and {Della Torre}, S. and {Gervasi}, M. and {Grandi}, D. and {Kudela}, K. and {Pensotti}, S. and {Rancoita}, P.G.", title = "{Proton and antiproton modulation in the heliosphere for different solar conditions and AMS-02 measurements prediction}", booktitle = "Astroparticle, Particle, Space Physics, Radiation Interaction, Detectors and Medical Physics Applications: Volume 6. Cosmic Rays for Particle and Astroparticle Physics. Proceedings of the 12th ICATPP Conference. Villa Olmo, Como, Italy, 7 – 8 October 2010", year = 2010, editor = "Leroy, C. and Rancoita, P.G. and Barone, M. and Gaddi, A. and Price, L. and Ruchti, R.", pages = "360--368 arXiv:1012.3086", doi = "10.1142/9789814329033_0046", url = "https://arxiv.org/abs/1012.3086", keywords = "Cosmic Rays, Heliosphere, Particle Drift" }P Bobik, G Boella, M J Boschini, S Della Torre, M Gervasi, D Grandi, K Kudela, S Pensotti and P G Rancoita.
2D stochastic Monte Carlo to evaluate the modulation of GCR for positive and negative periods.
Proc. of 21st European Cosmic Ray Symposium, Košice (Slovakia) 9-12/9/2008, page 248, 2009.
BibTeX@article{symposium2008, author = "{Bobik}, P. and {Boella}, G. and {Boschini}, M.J. and {Della Torre}, S. and {Gervasi}, M. and {Grandi}, D. and {Kudela}, K. and {Pensotti}, S. and {Rancoita}, P.G.", title = "2D stochastic Monte Carlo to evaluate the modulation of GCR for positive and negative periods", journal = "Proc. of 21st European Cosmic Ray Symposium, Ko\v{s}ice (Slovakia) 9-12/9/2008", year = 2009, pages = 248, organization = "21st European Cosmic Ray Symposium" }P Bobik, G Boella, M J Boschini, S Della Torre, M Gervasi, D Grandi, K Kudela, S Pensotti and P G Rancoita.
Helisphere modulation of Primary Cosmic Rays for the AMS-02 mission.
Proc. of the 31st ICRC, Lodz, 2009.
BibTeX@article{ICRC09, author = "{Bobik}, P. and {Boella}, G. and {Boschini}, M.J. and {Della Torre}, S. and {Gervasi}, M. and {Grandi}, D. and {Kudela}, K. and {Pensotti}, S. and {Rancoita}, P.G.", title = "{Helisphere modulation of Primary Cosmic Rays for the AMS-02 mission}", journal = "Proc. of the 31st ICRC, Lodz", year = 2009, organization = "31st ICRC" }P Bobik, G Boella, M J Boschini, Della S Torre, M Gervasi, D Grandi, K Kudela, S Pensotti and P G Rancoita.
DRIFT MODELS AND POLAR FIELD FOR COSMIC RAYS PROPAGATION IN THE HELIOSPHERE.
In Astroparticle, Particle and Space Physics, Detectors and Medical Physics Applications: Volume 5. Proceedings of the 11th Conference. Villa Olmo, Como, Italy, 5 – 9 October 2009. 2009, 760-764.
URL, DOI BibTeX@inproceedings{DellaTorre2009, author = "P. Bobik and G. Boella and M. J. Boschini and S. Della Torre and M. Gervasi and D. Grandi and K. Kudela and S. Pensotti and P. G. Rancoita", title = "DRIFT MODELS AND POLAR FIELD FOR COSMIC RAYS PROPAGATION IN THE HELIOSPHERE", booktitle = "Astroparticle, Particle and Space Physics, Detectors and Medical Physics Applications: Volume 5. Proceedings of the 11th Conference. Villa Olmo, Como, Italy, 5 – 9 October 2009", pages = "760-764", doi = "10.1142/9789814307529_0121", url = "http://www.worldscientific.com/doi/abs/10.1142/9789814307529_0121", eprint = "http://www.worldscientific.com/doi/pdf/10.1142/9789814307529_0121", publisher = "WORLD SCIENTIFIC", year = 2009 }P Bobik, M J Boschini, Della S Torre, M Gervasi, D Grandi, K Kudela and P G Rancoita.
GALACTIC COSMIC RAYS MODULATION AND PREDICTION FOR THE AMS-02 MISSION.
In Astroparticle, Particle and Space Physics, Detectors and Medical Physics Applications: Volume 5. Proceedings of the 11th Conference. Villa Olmo, Como, Italy, 5 – 9 October 2009. 2009, 210-219.
URL, DOI BibTeX@inproceedings{bobik2010a, author = "P. Bobik and M. J. Boschini and S. Della Torre and M. Gervasi and D. Grandi and K. Kudela and P. G. Rancoita", title = "GALACTIC COSMIC RAYS MODULATION AND PREDICTION FOR THE AMS-02 MISSION", booktitle = "Astroparticle, Particle and Space Physics, Detectors and Medical Physics Applications: Volume 5. Proceedings of the 11th Conference. Villa Olmo, Como, Italy, 5 – 9 October 2009", chapter = "", pages = "210-219", doi = "10.1142/9789814307529_0036", url = "http://www.worldscientific.com/doi/abs/10.1142/9789814307529_0036", eprint = "http://www.worldscientific.com/doi/pdf/10.1142/9789814307529_0036", publisher = "WORLD SCIENTIFIC", year = 2009 }P Bobik, M J Boschini, M Gervasi, D Grandi and P G Rancoita.
2D Stochastic Monte Carlo to evaluate the modulation of GCR for inner and outer solar system planets.
In Astroparticle, Particle and Space Physics, Detectors and Medical Physics Applications: Volume 4. Proceedings of the 10th Conference. Villa Olmo, Como, Italy, 8 – 12 October 2007. 2007, 881-885.
URL, DOI BibTeX@inproceedings{doi:10.1142/9789812819093_0147, author = "P. Bobik and M. J. Boschini and M. Gervasi and D. Grandi and P. G. Rancoita", title = "2D Stochastic Monte Carlo to evaluate the modulation of GCR for inner and outer solar system planets", booktitle = "Astroparticle, Particle and Space Physics, Detectors and Medical Physics Applications: Volume 4. Proceedings of the 10th Conference. Villa Olmo, Como, Italy, 8 – 12 October 2007", pages = "881-885", doi = "10.1142/9789812819093_0147", url = "http://www.worldscientific.com/doi/abs/10.1142/9789812819093_0147", eprint = "http://www.worldscientific.com/doi/pdf/10.1142/9789812819093_0147", publisher = "WORLD SCIENTIFIC", year = 2007 }P Bobik, G Boella, M J Boschini, M Gervasi, D Grandi, K Kudela, S Pensotti and P G Rancoita.
A stochastic Montecarlo approach to Solar modulation of GCR: evaluation of the proton flux at several distances from the Sun.
In Proc. of the 20th European Cosmic Rays Symposium (ECRS2006), September 5-9, 2006 (Lisbon, Portugal). 2006.
BibTeX@inproceedings{Bobik2007, author = "Bobik, P. and Boella, G. and Boschini, M.J. and Gervasi, M. and Grandi, D. and Kudela, K. and Pensotti,S. and Rancoita, P.G.", title = "A stochastic Montecarlo approach to Solar modulation of GCR: evaluation of the proton flux at several distances from the Sun", year = 2006, booktitle = "Proc. of the 20th European Cosmic Rays Symposium (ECRS2006), September 5-9, 2006 (Lisbon, Portugal)" }P Bobik, M J Boschini, M Gervasi, D Grandi and P G Rancoita.
A 2D stochastic Montecarlo for the solar modulation of GCR: a procedure to fit interplanetary parameters comparing to the experimental data.
In Astroparticle, Particle and Space Physics, Detectors and Medical Physics Applications: Volume 3. Proceedings of the 9th Conference Villa Olmo, Como, Italy, 17 – 21 October 2005. 2005, 206-211.
URL, DOI BibTeX@inproceedings{doi:10.1142/9789812773678_0034, author = "P. Bobik and M. J. Boschini and M. Gervasi and D. Grandi and P. G. Rancoita", title = "A 2D stochastic Montecarlo for the solar modulation of GCR: a procedure to fit interplanetary parameters comparing to the experimental data", booktitle = "Astroparticle, Particle and Space Physics, Detectors and Medical Physics Applications: Volume 3. Proceedings of the 9th Conference Villa Olmo, Como, Italy, 17 – 21 October 2005", pages = "206-211", doi = "10.1142/9789812773678_0034", url = "http://www.worldscientific.com/doi/abs/10.1142/9789812773678_0034", eprint = "http://www.worldscientific.com/doi/pdf/10.1142/9789812773678_0034", publisher = "WORLD SCIENTIFIC", year = 2005 }P Bobik, M Gervasi, D Grandi, P G Rancoita and I G Usoskin.
2D stochastic simulation model of cosmic ray modulation: comparison with experimental data.
In A Wilson (ed.). Solar Variability as an Input to the Earth's Environment, International Solar Cycle Studies (ISCS) Symposium, 23 - 28 June 2003, Tatranska Lomnica, Slovak Republic. 535. 2003, 637-640.
BibTeX@inproceedings{2003ESASP.535..637B, author = "{Bobik}, P. and {Gervasi}, M. and {Grandi}, D. and {Rancoita}, P.G. and {Usoskin}, I.G.", title = "{2D stochastic simulation model of cosmic ray modulation: comparison with experimental data}", keywords = "Galactic Cosmic Rays, Modulation, Heliosphere", booktitle = "Solar Variability as an Input to the Earth's Environment, International Solar Cycle Studies (ISCS) Symposium, 23 - 28 June 2003, Tatranska Lomnica, Slovak Republic.", year = 2003, series = "ESA Special Publication", volume = 535, editor = "{Wilson}, A.", month = "", pages = "637-640", adsurl = "http://adsabs.harvard.edu/abs/2003ESASP.535..637B", adsnote = "Provided by the SAO/NASA Astrophysics Data System" }P Bobik, M Gervasi, D Grandi, P G Rancoita and I G Usoskin.
Solar modulation Models: a comparison through a 2D stochastic simulation.
In Astroparticle, Particle and Space Physics, Detectors and Medical Physics Applications: Volume 2. Proceedings of the 8th Conference Villa Olmo, Como, Italy, 6 – 11 October 2003. 2003, 23-28.
URL, DOI BibTeX@inproceedings{doi:10.1142/9789812702708_0004, author = "P. Bobik and M. Gervasi and D. Grandi and P. G. Rancoita and I. G. Usoskin", title = "Solar modulation Models: a comparison through a 2D stochastic simulation", booktitle = "Astroparticle, Particle and Space Physics, Detectors and Medical Physics Applications: Volume 2. Proceedings of the 8th Conference Villa Olmo, Como, Italy, 6 – 11 October 2003", pages = "23-28", doi = "10.1142/9789812702708_0004", url = "http://www.worldscientific.com/doi/abs/10.1142/9789812702708_0004", eprint = "http://www.worldscientific.com/doi/pdf/10.1142/9789812702708_0004", publisher = "WORLD SCIENTIFIC", year = 2003 }M Gervasi, P G Rancoita and I G Usoskin.
Transport of Galactic Cosmic Rays in the Heliosphere: Stochastic Simulation Approach.
In Proceedings of the 26th International Cosmic Ray Conference (ICRC2016), August 17-25, 1999 (Salt Lake City, USA). 1999, 69.
BibTeX@inproceedings{Gervasi1999b, author = "Gervasi, M. and Rancoita, P.G. and Usoskin, I.G.", title = "Transport of Galactic Cosmic Rays in the Heliosphere: Stochastic Simulation Approach", year = 1999, booktitle = "Proceedings of the 26th International Cosmic Ray Conference (ICRC2016), August 17-25, 1999 (Salt Lake City, USA)", pages = 69 }M Gervasi, P G Rancoita, I G Usoskin and G A Kovaltsov.
Monte-Carlo approach to Galactic Cosmic Ray propagation in the Heliosphere.
Nuclear Physics B Proceedings Supplements, 6th ICATPP Conf., Como 5-9 Oct 1998 78:26-31, 1998.
DOI BibTeX@article{1999NuPhS..78...26G, author = "{Gervasi}, M. and {Rancoita}, P.G. and {Usoskin}, I.G. and {Kovaltsov}, G.A.", title = "{Monte-Carlo approach to Galactic Cosmic Ray propagation in the Heliosphere}", journal = "Nuclear Physics B Proceedings Supplements, 6th ICATPP Conf., Como 5-9 Oct 1998", year = 1998, month = "", volume = 78, pages = "26-31", doi = "10.1016/S0920-5632(99)00518-6", adsurl = "http://adsabs.harvard.edu/abs/1999NuPhS..78...26G", adsnote = "Provided by the SAO/NASA Astrophysics Data System" }