Neutron monitor latitude survey of cosmic ray intensity during the 1986/1987 solar minimum

Moraal, H.; Potgieter, M. S.; Stoker, P. H.; Walt, A. J. van der

doi:10.1029/ja094ia02p01459

Cited by 90 publications

(59 citation statements)

References 5 publications

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“…The primary flux is nearly omnidirectional and therefore a complete description of primary cosmic-ray access to the Earth requires calculation of cutoff rigidities for all angles of incidence (Clem et al, 1997). The reliability of R c has been confirmed by numerous sea level latitude surveys (Moraal et al, 1989;Dorman et al, 2000).…”

Section: The Geomagnetic Field and Cosmogenic Nuclide Productionmentioning

confidence: 99%

Interstellar-Terrestrial Relations: Variable Cosmic Environments, The Dynamic Heliosphere, and Their Imprints on Terrestrial Archives and Climate

et al. 2007

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Abstract. In recent years the variability of the cosmic ray flux has become one of the main issues interpreting cosmogenic elements and especially their connection with climate. In this review, an interdisciplinary team of scientists brings together our knowledge of the evolution and modulation of the cosmic ray flux from its origin in the Milky Way, during its propagation through the heliosphere, up to its interaction with the Earth's magnetosphere, resulting, finally, in the production of cosmogenic isotopes in the Earth' atmosphere. The interpretation of the cosmogenic isotopes and the cosmic ray -cloud connection are also intensively discussed. Finally, we discuss some open questions.

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Section: The Geomagnetic Field and Cosmogenic Nuclide Productionmentioning

confidence: 99%

Interstellar-Terrestrial Relations: Variable Cosmic Environments, The Dynamic Heliosphere, and Their Imprints on Terrestrial Archives and Climate

et al. 2007

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“…[5] Latitude surveys have been carried out with shipborne neutron monitors [Rose et al, 1956;Potgeiter et al, 1980;Villoresi et al, 2000] and overland [Bachelet et al, 1964;Carmichael et al, 1969;Moraal et al, 1989]; also, airborne surveys have been made [Simpson and Fagot, 1953;Stoker and Moraal, 1995]. Inter-comparison of surveys at different times became easier when the trajectory-based cut-offs became available [Kondo and Kodama, 1965].…”

Section: Response Functionsmentioning

confidence: 99%

Cosmic ray detector response to transient solar modulation: Forbush decreases

Ahluwalia

Fikani

2007

J. Geophys. Res.

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[1] The observed modulation of galactic cosmic ray (GCR) intensity, on time and spatial scales, contains information regarding their transport in the heliosphere. One way to extract crucial information from the data is to study the rigidity dependence of modulation. A methodology is described to study the rigidity dependence of the short-term variations in galactic cosmic ray intensity Earth, in terms of the median rigidity of detector response (R m ) to cosmic ray spectrum. We define R m as the rigidity below which lies 50% of detector counting rate. For neutron monitors (NMs), it is easily calculated from the latitude survey obtained at sea level and higher elevations. We compute R m values for some NM sites; solar cycle dependence for them is shown to be small. Their practical utility is demonstrated in a study of transient cosmic ray solar modulation (Forbush decreases (FDs)), using data published in the literature. We plot the rigidity dependence of the amplitudes of three large Forbush decreases that occurred during the declining phase of three solar cycles (19, 20, and 21). We show that the Forbush decrease amplitude varies inversely with R m over a large range (1 to 300 GV) of GCR rigidities. Thereby, we rule out the existence of a ''transition rigidity'' suggested by Jokipii even for a short-term modulation (large Forbush decreases). We speculate that the force field model may be applicable to large Forbush decreases.

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“…Repeating this analysis on 20 minute subsets of the data, and using a published response function (Moraal et al 1989), we calculated (Fig. 4) the expected count rate increase for a sea level neutron monitor.…”

Section: Discussionmentioning

confidence: 99%

Solar Energetic Particle Spectrum on 2006 December 13 Determined by IceTop

Abbasi¹,

Ackermann²,

Adams

et al. 2008

ApJ

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On 2006 December 13 the IceTop air shower array at the South Pole detected a major solar particle event. By numerically simulating the response of the IceTop tanks, which are thick Cerenkov detectors with multiple thresholds deployed at high altitude with no geomagnetic cutoff, we determined the particle energy spectrum in the energy range 0.6-7.6 GeV. This is the first such spectral measurement using a single instrument with a welldefined viewing direction. We compare the IceTop spectrum and its time evolution with previously published results and outline plans for improved resolution of future solar particle spectra.

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Neutron monitor latitude survey of cosmic ray intensity during the 1986/1987 solar minimum

Cited by 90 publications

References 5 publications

Interstellar-Terrestrial Relations: Variable Cosmic Environments, The Dynamic Heliosphere, and Their Imprints on Terrestrial Archives and Climate

Interstellar-Terrestrial Relations: Variable Cosmic Environments, The Dynamic Heliosphere, and Their Imprints on Terrestrial Archives and Climate

Cosmic ray detector response to transient solar modulation: Forbush decreases

Solar Energetic Particle Spectrum on 2006 December 13 Determined by IceTop

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