scholarly journals Galactic cosmic ray H and He nuclei energy spectra measured by Voyagers 1 and 2 near the heliospheric termination shock in positive and negative solar magnetic polarity cycles

2008 ◽  
Vol 113 (A10) ◽  
Author(s):  
W. R. Webber ◽  
A. C. Cummings ◽  
F. B. McDonald ◽  
E. C. Stone ◽  
B. Heikkila ◽  
...  
Keyword(s):  
Cosmic Ray ◽  
Magnetic Polarity ◽  
Termination Shock ◽  
Energy Spectra ◽  
Galactic Cosmic Ray

scholarly journals Effects of the solar wind termination shock and heliosheath on theheliospheric modulation of galactic and anomalous Helium

2004 ◽  
Vol 22 (8) ◽  
pp. 3063-3072 ◽  
Author(s):  
U. W. Langner ◽  
M. S. Potgieter
Keyword(s):  
Solar Wind ◽  
Cosmic Ray ◽  
Magnetic Polarity ◽  
Termination Shock ◽  
Shock Acceleration ◽  
Diffusive Shock Acceleration ◽  
Cosmic Ray Modulation ◽  
Low Energies ◽  
Solar Wind Termination Shock ◽  
Charge Sign

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

scholarly journals Galactic cosmic-ray energy spectra and expected solar events at the time of future space missions

2011 ◽  
Vol 28 (9) ◽  
pp. 094005 ◽  
Author(s):  
C Grimani ◽  
H M Araújo ◽  
M Fabi ◽  
A Lobo ◽  
I Mateos ◽  
...  
Keyword(s):  
Cosmic Ray ◽  
Space Missions ◽  
Energy Spectra ◽  
Future Space ◽  
Solar Events ◽  
Galactic Cosmic Ray

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

2020 ◽  
Author(s):  
Johannes Marquardt ◽  
Bernd Heber ◽  
Robert Elftmann ◽  
Robert Wimmer-Schweingruber
Keyword(s):  
Energetic Particle ◽  
Solar Minimum ◽  
Cosmic Ray ◽  
High Energy ◽  
Energy Spectra ◽  
Particle Detector ◽  
Quiet Time ◽  
Transport Models ◽  
Galactic Cosmic Ray ◽  
Insight Into

<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>

scholarly journals Energy spectra of carbon and oxygen with HELIOS E6

2018 ◽  
Vol 610 ◽  
pp. A42 ◽  
Author(s):  
J. Marquardt ◽  
B. Heber ◽  
M. S. Potgieter ◽  
R. D. Strauss
Keyword(s):  
Cosmic Rays ◽  
Cosmic Ray ◽  
Energy Spectra ◽  
Quiet Time ◽  
Transport Models ◽  
Radial Gradient ◽  
The One ◽  
Galactic Cosmic Ray ◽  
Good Agreement ◽  
Inner Heliosphere

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.

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