Energy spectra of carbon and oxygen - Predictions from HELIOS E6 for Solar Orbiter HET

Author(s):  
Johannes Marquardt ◽  
Bernd Heber ◽  
Robert Elftmann ◽  
Robert Wimmer-Schweingruber

<p>Anomalous cosmic rays (ACRs) are well-suited to probe the transport conditions of energetic particles in the innermost heliosphere. We revisit the HELIOS Experiment 6 (E6) data in view of the upcoming Solar Orbiter Energetic Particle Detector (EPD) suite that will perform measurements during a comparable solar minimum within the same distance.</p><p>Adapting the HELIOS energy ranges for oxygen and carbon to the ones given by the High Energy Telescope (HET) allows us to determine predictions for the upcoming measurements but also to put constraints on particle transport models that provide new insight into the boundary conditions close to the Sun.</p><p>We present here the adapted energy spectra of galactic cosmic ray (GCR) carbon and oxygen, as well as of ACR oxygen during solar quiet time periods between 1975 to 1977. Due to the higher energy threshold of HET in comparison to E6 gradients of about 20% at 15 MeV/nucleon are expected. The largest ACR gradient measured by E6 was obtained to be about 75% between 9 and 13 MeV/nucleon and 0.4 AU and 1 AU.</p>

2018 ◽  
Vol 610 ◽  
pp. A42 ◽  
Author(s):  
J. Marquardt ◽  
B. Heber ◽  
M. S. Potgieter ◽  
R. D. Strauss

Context. Anomalous cosmic rays (ACRs) are well-suited to probe the transport conditions of cosmic rays in the inner heliosphere. We revisit the HELIOS data not only in view of the upcoming Solar Orbiter experiment but also to put constraints on particle transport models in order to provide new insight into the boundary conditions close to the Sun. Aims. We present here the energy spectra of galactic cosmic ray (GCR) carbon and oxygen, as well as of ACR oxygen during solar quiet time periods between 1975 to 1977, utilizing both HELIOS spacecraft at distances between ~0.3 and 1 AU. The radial gradient (Gr ≈ 50%/AU) of 9–28.5 MeV ACR oxygen in the inner heliosphere is about three times larger than the one determined between 1 and 10 AU by utilizing the Pioneer 10 measurements. Methods. The chemical composition as well as the energy spectra have been derived by applying the dE∕dx − E-method. In order to derive these values, special characteristics of the instrument have been taken into account. Results. A good agreement of the GCR energy spectra of carbon and oxygen measured by the HELIOS E6 instrument between 0.3 and 1 AU and the Interplanetary Monitoring Platform (IMP) 8 at 1 AU was found. For ACR oxygen, we determined a radial gradient of about 50%/AU that is three times larger than the one between 7 and 14 AU, indicating a strong change in the inner heliosphere.


2019 ◽  
Vol 9 ◽  
pp. A9 ◽  
Author(s):  
Tatsuhiko Sato ◽  
Ryuho Kataoka ◽  
Daikou Shiota ◽  
Yûki Kubo ◽  
Mamoru Ishii ◽  
...  

Real-time estimation of cosmic-ray fluxes on satellite orbits is one of the greatest challenges in space weather research. Therefore, we develop a system for nowcasting and forecasting the galactic cosmic ray (GCR) and solar energetic particle (SEP) fluxes at any location in the magnetosphere and ionosphere during ground-level enhancement (GLE) events. It is an extended version of the WArning System for AVIation Exposure to SEP (WASAVIES), which can determine event profiles by using real-time data of the count rates of several neutron monitors (NMs) at the ground level and high-energy proton fluxes observed by Geostationary Operational Environmental Satellites (GOES) satellites. The extended version, called WASAVIES-EO, can calculate the GCR and SEP fluxes outside a satellite based on its two-line element (TLE) data. Moreover, organ absorbed-dose and dose-equivalent rates of astronauts in the International Space Station (ISS) can be estimated using the system, considering its shielding effect. The accuracy of WASAVIES-EO was validated based on the dose rates measured in ISS, as well as based on high-energy proton fluxes observed by POES satellites during large GLEs that have occurred in the 21st century. Agreement between the nowcast and forecast dose rates in ISS, especially in terms of their temporal structures, indicates the usefulness of the developed system for future mission operations.


2013 ◽  
Vol 770 (2) ◽  
pp. 117 ◽  
Author(s):  
K. A. Lave ◽  
M. E. Wiedenbeck ◽  
W. R. Binns ◽  
E. R. Christian ◽  
A. C. Cummings ◽  
...  

2021 ◽  
Author(s):  
Zigong Xu ◽  
Johan L. Freiherr von Forstner ◽  
Patrick Kühl ◽  
Nils Janitzek ◽  
César Martín ◽  
...  

<p>As part of the Energetic Particle Detector (EPD) suite onboard Solar Orbiter, the High Energy Telescope has been launched on its mission to the Sun on February 9, 2020, and has been measuring energetic particles since it was first switched on about two weeks after launch. Using their double-ended telescopes, the two HET units provide measurements of ions above 7 MeV/nuc and electrons above 300 keV in four viewing directions. HET observed several Solar Energetic Particle (SEPs) events during the cruise phase, including the first one with a broad energy coverage (up to ~100MeV) on 29 Nov 2020. Being the first larger SEP event in a phase of rising solar activity, these measurements have already attracted extensive attention of the community. Apart from the SEPs, the HET can be used to observe the Galactic cosmic radiation (GCR) and its temporal variation. The GCR measurements can be also utilized for the validation of the energy response of HET. The overall spectra observed by HET are as expected, except for calibration issues in some specific energy bins that we are still investigating. Finally, the HET also observed several Forbush Decreases (FD), i.e. cosmic ray decreases caused by CMEs and their embedded magnetic field. Here, the capabilities and data products of HET, as well as first measurements of SEPs, GCR and FDs are presented. </p>


2021 ◽  
Vol 502 (4) ◽  
pp. 5821-5838
Author(s):  
Ottavio Fornieri ◽  
Daniele Gaggero ◽  
Silvio Sergio Cerri ◽  
Pedro De La Torre Luque ◽  
Stefano Gabici

ABSTRACT We present a comprehensive study about the phenomenological implications of the theory describing Galactic cosmic ray scattering on to magnetosonic and Alfvénic fluctuations in the GeV−PeV domain. We compute a set of diffusion coefficients from first principles, for different values of the Alfvénic Mach number and other relevant parameters associated with both the Galactic halo and the extended disc, taking into account the different damping mechanisms of turbulent fluctuations acting in these environments. We confirm that the scattering rate associated with Alfvénic turbulence is highly suppressed if the anisotropy of the cascade is taken into account. On the other hand, we highlight that magnetosonic modes play a dominant role in Galactic confinement of cosmic rays up to PeV energies. We implement the diffusion coefficients in the numerical framework of the dragon code, and simulate the equilibrium spectrum of different primary and secondary cosmic ray species. We show that, for reasonable choices of the parameters under consideration, all primary and secondary fluxes at high energy (above a rigidity of $\simeq 200 \, \mathrm{GV}$) are correctly reproduced within our framework, in both normalization and slope.


2015 ◽  
Vol 2 ◽  
pp. 39-44 ◽  
Author(s):  
P. L. Biermann ◽  
L. I. Caramete ◽  
A. Meli ◽  
B. N. Nath ◽  
E.-S. Seo ◽  
...  

Abstract. A model is introduced, in which the irregularity spectrum of the Galactic magnetic field beyond the dissipation length scale is first a Kolmogorov spectrum k-5/3 at small scales λ = 2 π/k with k the wave-number, then a saturation spectrum k-1, and finally a shock-dominated spectrum k-2 mostly in the halo/wind outside the Cosmic Ray disk. In an isotropic approximation such a model is consistent with the Interstellar Medium (ISM) data. With this model we discuss the Galactic Cosmic Ray (GCR) spectrum, as well as the extragalactic Ultra High Energy Cosmic Rays (UHECRs), their chemical abundances and anisotropies. UHECRs may include a proton component from many radio galaxies integrated over vast distances, visible already below 3 EeV.


2018 ◽  
Vol 2018 ◽  
pp. 1-23 ◽  
Author(s):  
Daniele Gaggero ◽  
Mauro Valli

The quest for the elusive dark matter (DM) that permeates the Universe (and in general the search for signatures of physics beyond the Standard Model at astronomical scales) provides a unique opportunity and a tough challenge to the high energy astrophysics community. In particular, the so-called DMindirect searches—mostly focused on a class of theoretically well-motivated DM candidates such as the weakly interacting massive particles—are affected by a complex astrophysical background of cosmic radiation. The understanding and modeling of such background require a deep comprehension of an intricate classical plasma physics problem, i.e., the interaction between high energy charged particles, accelerated in peculiar astrophysical environments, and magnetohydrodynamic turbulence in the interstellar medium of our galaxy. In this review we highlight several aspects of this exciting interplay between the most recent claims of DM annihilation/decay signatures from the sky and the galactic cosmic-ray research field. Our purpose is to further stimulate the debate about viable astrophysical explanations, discussing possible directions that would help breaking degeneracy patterns in the interpretation of current data. We eventually aim to emphasize how a deep knowledge on the physics of CR transport is therefore required to tackle the DM indirect search program at present and in the forthcoming years.


2011 ◽  
Vol 28 (9) ◽  
pp. 094005 ◽  
Author(s):  
C Grimani ◽  
H M Araújo ◽  
M Fabi ◽  
A Lobo ◽  
I Mateos ◽  
...  

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