scholarly journals Variability of quiet-time diurnal amplitude and phase of cosmic ray count rates in the mid- and high latitudes

2017 ◽  
Vol 12 (22) ◽  
pp. 295-307
Author(s):  
Ugochukwu Okiyi ◽  
Kingsley C. Okpala ◽  
James O. Tsor ◽  
Friday Egbunu
2005 ◽  
Vol 23 (2) ◽  
pp. 385-391 ◽  
Author(s):  
R. Stening ◽  
T. Reztsova ◽  
D. Ivers ◽  
J. Turner ◽  
D. Winch

Abstract. The records of an array of magnetometers set up across the Australian mainland are examined. In addition to a well-defined current whorl corresponding to the ionospheric Sq current system, another system of eastward flowing currents is often found in the early morning. The system is most easily identified at observatories poleward of the focus of the Sq system, where a morning reversal from eastward to westward currents can be seen. The time of the reversal is usually later, sometimes up to 12h local noon, in June (Southern Winter) than in other seasons. There is some evidence of a similar current system at other longitudes and in the Northern Hemisphere. An important outcome of the study is that it enables identification of which features of a daily variation of the northward magnetic field ΔX relate to an Sq current whorl and which must be attributed to some other current system.


1964 ◽  
Vol 133 (3B) ◽  
pp. B818-B827 ◽  
Author(s):  
C. E. Fichtel ◽  
D. E. Guss ◽  
G. R. Stevenson ◽  
C. J. Waddington
Keyword(s):  

Author(s):  
J. Krall ◽  
J. D. Huba

The Naval Research Laboratory (NRL) Sami2 is Another Model of the Ionosphere (SAMI2) and Sami3 is Also a Model of the Ionosphere (SAMI3) ionosphere/plasmasphere codes have shown that thermosphere composition and winds significantly affect H+ outflows from the topside ionosphere. In particular, O density inhibits upward diffusion of O+ from the ionosphere F layer, especially during solar maximum conditions. In addition, winds affect the quiet-time latitudinal extent of the F layer, affecting densities at mid-to-high latitudes that are the source of plasmasphere refilling outflows. Evidence for these effects is reviewed and prospects for forecasting these outflows are explored. Open questions for future research are highlighted.


1956 ◽  
Vol 34 (9) ◽  
pp. 968-984 ◽  
Author(s):  
D. C. Rose ◽  
K. B. Fenton ◽  
J. Katzman ◽  
J. A. Simpson

Results are presented of cosmic ray measurements taken at sea level during 1954–55 from the Arctic to the Antarctic. The equipment consisted of a neutron monitor and a meson telescope. Latitude effects of 1.77 for the nucleonic component and 1.15 for the meson component were measured. The longitude effect at the equator was much less than expected on the basis of the geomagnetic eccentric dipole and the longitude effect at intermediate northern latitudes shows that the longitude of the effective eccentric dipole is considerably west of that of the geomagnetic eccentric dipole. In a previous paper by the same authors, the positions of the equatorial minima were combined with other published cosmic ray measurements to calculate a new cosmic ray geomagnetic equator. In this paper new coordinates are derived on the assumption that these equatorial coordinates apply to a new eccentric dipole, and, therefore, that the equatorial coordinates may be extended to high latitudes. When the complete results are plotted on these coordinates, it is found that an eccentric dipole representation of the earth's magnetic field is inconsistent with the combined observations at all latitudes.


2020 ◽  
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.


1978 ◽  
Vol 83 (A4) ◽  
pp. 1633 ◽  
Author(s):  
W. -H. Ip ◽  
W. Fillius ◽  
A. Mogro-Campero ◽  
L. J. Gleeson ◽  
W. I. Axford
Keyword(s):  

1955 ◽  
Vol 99 (1) ◽  
pp. 198-209 ◽  
Author(s):  
L. H. Meredith ◽  
J. A. Van Allen ◽  
M. B. Gottlieb

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