Galactic cosmic ray hydrogen spectra and radial gradients in the inner heliosphere measured by the HELIOS Experiment 6

Marquardt, J.; Heber, B.

doi:10.1051/0004-6361/201935413

Cited by 15 publications

(16 citation statements)

References 21 publications

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“…The comparison between Ulysses and Pamela overlapping measurements indicated Orbiter. In the recent paper by Marquardt & Heber (2019) the Helios data radial gradients of the GCR flux were found of 6.6±4% above 50 MeV and 2±2.5% between 250 and 700 MeV between 0.4 and 1 AU: these results agree with those by Pamela/Ulysses within errors. In conclusion, the variations of the GCR flux along the Solar Orbiter orbit are expected to be of a few % at most and, consequently, it is plausible to assume that models for cosmic-ray modulation developed on the basis of observations gathered near Earth will also apply to Solar Orbiter.…”

Section: Gcr Flux Radial and Latitudinal Gradients In The Inner Helio...supporting

confidence: 81%

Cosmic-ray flux predictions and observations for and with Metis on board Solar Orbiter

Grimani,

Andretta,

Chioetto

et al. 2021

Preprint

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Context. The Metis coronagraph is one of the remote sensing instruments hosted on board the ESA/NASA Solar Orbiter mission. Metis is devoted to carry out the first simultaneous imaging of the solar corona in both visible light (VL) and ultraviolet (UV). Highenergy particles penetrate spacecraft materials and may limit the performance of on-board instruments. A study of galactic cosmic-ray (GCR) tracks observed in the first VL images gathered by Metis during the commissioning phase for a total of 60 seconds of exposure time is presented here. A similar analysis is planned for the UV channel. Aims. A prediction of the GCR flux up to hundreds of GeV is made here for the first part of the Solar Orbiter mission to study the Metis coronagraph performance. Methods. GCR model predictions are compared to observations gathered on board Solar Orbiter by the EPD/HET experiment in the range 10 MeV-100 MeV in the summer 2020 and with previous measurements. Estimated cosmic-ray fluxes above 70 MeV n −1 have been also parameterized and used for Monte Carlo simulations aiming at reproducing the cosmic-ray track observations in the Metis coronagraph VL images. Same parameterizations can also be used to study the performance of other detectors. Results. By comparing observations of cosmic-ray tracks in the Metis VL images with FLUKA Monte Carlo simulations of cosmicray interactions in the VL detector, it is found that cosmic rays fire a fraction of the order of 10 −4 of the whole image pixel sample. Therefore, cosmic rays do not affect sensibly the quality of Metis VL images. It is also found that the overall efficiency for cosmic-ray identification in the Metis VL images is approximately equal to the contribution of Z>2 particles. As a result, the Metis coronagraph may play the role of a proton monitor for long-term GCR variations during the overall mission duration.

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Section: Gcr Flux Radial and Latitudinal Gradients In The Inner Helio...supporting

confidence: 81%

Cosmic-ray flux predictions and observations for and with Metis on board Solar Orbiter

Grimani,

Andretta,

Chioetto

et al. 2021

Preprint

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“…As a result, the Helios data are representative of the cosmic-ray bulk variations that are to be experienced by Solar Orbiter, which will also reach maximum distances from the Sun of about 1 AU. In the recent paper by Marquardt & Heber (2019), the Helios proton data radial gradients of the GCR flux were found to be 6.6 ± 4% above 50 MeV and 2 ± 2.5% between 250 and 700 MeV between 0.4 and 1 AU. These results are in agreement with those from Pamela/Ulysses (within the statistical and systematic errors).…”

Section: Galactic Cosmic-ray Flux Radial and Latitudinal Gradients In The Inner Heliospherementioning

confidence: 92%

“…Positive (negative) latitudinal gradients are observed during positive (negative) polarity periods. In addition, Experiment 6 (E6) on board Helios-A and Helios-B provided ion data from four to several hundreds of MeV n −1 (Winkler 1976;Marquardt & Heber 2019). The Helios-A and Helios-B S/C were launched on December 10, 1974 and January 15, 1976 during a positive polarity epoch and were sent into ecliptic orbits of 190-day and 185-day periods around the Sun.…”

Section: Galactic Cosmic-ray Flux Radial and Latitudinal Gradients In The Inner Heliospherementioning

confidence: 99%

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Cosmic-ray flux predictions and observations for and with Metis on board Solar Orbiter

Grimani

Andretta

Chioetto

et al. 2021

A&A

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Context. The Metis coronagraph is one of the remote sensing instruments hosted on board the ESA/NASA Solar Orbiter mission. Metis is devoted to carry out the first simultaneous imaging of the solar corona in both visible light (VL) and ultraviolet (UV). High-energy particles can penetrate spacecraft materials and may limit the performance of the on-board instruments. A study of the galactic cosmic-ray (GCR) tracks observed in the first VL images gathered by Metis during the commissioning phase is presented here. A similar analysis is planned for the UV channel. Aims. We aim to formulate a prediction of the GCR flux up to hundreds of GeV for the first part of the Solar Orbiter mission to study the performance of the Metis coronagraph. Methods. The GCR model predictions are compared to observations gathered on board Solar Orbiter by the High-Energy Telescope in the range between 10 MeV and 100 MeV in the summer of 2020 as well as with the previous measurements. Estimated cosmic-ray fluxes above 70 MeV n−1 have been also parameterized and used for Monte Carlo simulations aimed at reproducing the cosmic-ray track observations in the Metis coronagraph VL images. The same parameterizations can also be used to study the performance of other detectors. Results. By comparing observations of cosmic-ray tracks in the Metis VL images with FLUKA Monte Carlo simulations of cosmic-ray interactions in the VL detector, we find that cosmic rays fire only a fraction, on the order of 10−4, of the whole image pixel sample. We also find that the overall efficiency for cosmic-ray identification in the Metis VL images is approximately equal to the contribution of Z ≥ 2 GCR particles. A similar study will be carried out during the whole of the Solar Orbiter’s mission duration for the purposes of instrument diagnostics and to verify whether the Metis data and Monte Carlo simulations would allow for a long-term monitoring of the GCR proton flux.

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“…The E6 Instruments on the Helios spacecrafts have shown that adding a Cherenkov detector behind the detector stack can be utilized in order to distinguish between both directions (Marquardt and Heber, 2019) while the COSPIN/KET instrument on Ulysses (Simpson et al, 1992) has proven the possibility to distinguish between relativistic protons up to 2.1 GeV and electrons utilizing an By utilizing the increased on-board processing capabilities of these state of the art instruments compared to the 25 year old EPHIN electronics, the proposed improvements could be included without the need of significant higher telemetry rate. For example, the 2.8 Gbit per orbit telemetry from PSP/IS IS/EPI-Hi translates to an average of 192 bit per second for the first orbit of days which is similar to EPHINs nominal telemetry rate of 172 bit per second.…”

Section: Lessons Learned and Possible Improvementsmentioning

confidence: 99%

The Electron Proton Helium INstrument as an example for a Space Weather Radiation Instrument

Kühl

Heber

Gómez-Herrero

et al. 2020

J. Space Weather Space Clim.

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The near-Earth energetic particle environment has been monitored since the 1970's. With the increasing importance of quantifying the radiation risk for, e.g. for the human exploration of the Moon and Mars, it is essential to continue and further improve these measurements. The Electron Proton Helium INstrument (EPHIN) on-board SOHO continually provides these data sets to the solar science and space weather communities since 1995. Here, we introduce the numerous data products developed over the years and present space weather related applications. Important design features that have led to EPHINs success as well as lessons learned and possible improvements to the instrument are also discussed with respect to the next generation of particle detectors.

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Galactic cosmic ray hydrogen spectra and radial gradients in the inner heliosphere measured by the HELIOS Experiment 6

Cited by 15 publications

References 21 publications

Cosmic-ray flux predictions and observations for and with Metis on board Solar Orbiter

Cosmic-ray flux predictions and observations for and with Metis on board Solar Orbiter

Cosmic-ray flux predictions and observations for and with Metis on board Solar Orbiter

The Electron Proton Helium INstrument as an example for a Space Weather Radiation Instrument

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