Long-term cosmic ray modulation in the period 1966-1972 and interplanetary magnetic fields

This paper is concerned with the expected deviations in the production rate of natural 14C on the earth due to changes in solar activity. We review the published estimates of the global production rates of 14C due to galactic and solar cosmic ray particles, and present new estimates of the expected secular variations in 14C production, taking into account the latest information available on galactic cosmic ray modulation and long-term variations in solar activity.

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Interplanetary magnetic fields, their fluctuations, and cosmic ray variations

Journal of Geophysical Research Atmospheres ◽

10.1029/ja081i007p01453 ◽

1976 ◽

Vol 81 (7) ◽

pp. 1453-1456 ◽

Cited By ~ 11

Author(s):

E. Barouch ◽

J. W. Sari

Keyword(s):

Magnetic Fields ◽

Cosmic Ray ◽

Interplanetary Magnetic Fields

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Reconstructing the long-term cosmic ray intensity: linear relations do not work

Annales Geophysicae ◽

10.5194/angeo-21-863-2003 ◽

2003 ◽

Vol 21 (4) ◽

pp. 863-867 ◽

Cited By ~ 15

Author(s):

K. Mursula ◽

I. G. Usoskin ◽

G. A. Kovaltsov

Keyword(s):

Cosmic Ray ◽

Geomagnetism And Paleomagnetism ◽

Cosmic Ray Intensity ◽

Linear Relations ◽

Cosmic Ray Modulation ◽

Interplanetary Physics ◽

Long Time ◽

Time Variations ◽

Cosmic Ray Flux

Abstract. It was recently suggested (Lockwood, 2001) that the cosmic ray intensity in the neutron monitor energy range is linearly related to the coronal source flux, and can be reconstructed for the last 130 years using the long-term coronal flux estimated earlier. Moreover, Lockwood (2001) reconstructed the coronal flux for the last 500 years using a similar linear relation between the flux and the concentration of cosmogenic 10 Be isotopes in polar ice. Here we show that the applied linear relations are oversimplified and lead to unphysical results on long time scales. In particular, the cosmic ray intensity reconstructed by Lockwood (2001) for the last 130 years has a steep trend which is considerably larger than the trend estimated from observations during the last 65 years. Accordingly, the reconstructed cosmic ray intensity reaches or even exceeds the local interstellar cosmic ray flux around 1900. We argue that these unphysical results obtained when using linear relations are due to the oversimplified approach which does not take into account the complex and essentially nonlinear nature of long-term cosmic ray modulation in the heliosphere. We also compare the long-term cosmic ray intensity based on a linear treatment with the reconstruction based on a recent physical model which predicts a considerably lower cosmic ray intensity around 1900.Key words. Interplanetary physics (cosmic rays; heliopause and solar wind termination) – Geomagnetism and paleomagnetism (time variations, secular and long-term)

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Solar Drivers of 11-yr and Long-Term Cosmic Ray Modulation

Cosmic Rays in the Heliosphere - Space Sciences Series of ISSI ◽

10.1007/978-1-4614-9200-9_2 ◽

2011 ◽

pp. 3-19

Author(s):

E. W. Cliver ◽

I. G. Richardson ◽

A. G. Ling

Keyword(s):

Cosmic Ray ◽

Cosmic Ray Modulation

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Cosmic ray modulation in high and middle latitudes during solar cycles 22 and 23

Canadian Journal of Physics ◽

10.1139/cjp-2014-0290 ◽

2015 ◽

Vol 93 (1) ◽

pp. 100-104 ◽

Cited By ~ 1

Author(s):

Kingsley Chukwudi Okpala ◽

Francisca Nneka Okeke ◽

Anselem Ikechukwu Ugwuoke

Keyword(s):

Cosmic Rays ◽

Dynamic Pressure ◽

Cosmic Ray ◽

Galactic Cosmic Rays ◽

Proton Density ◽

Solar Cycles ◽

Middle Latitudes ◽

Cosmic Ray Modulation ◽

Interaction Regions

Galactic cosmic rays are modulated in the heliosphere primarily by the global merged interaction regions with intense magnetic fields, which leads to a decrease in galactic cosmic rays throughout the heliosphere. Using long-term averages of solar wind (SW) component parameters in addition to cosmic ray count rates of four neutron monitors with different rigidity cutoffs, we analyzed the effect of these SW components on the count rates under different interplanetary magnetic field (IMF) disturbance levels. From first-order partial correlation, we found that the IMF-B was the most dominant modulating parameter, especially during quiet conditions and the SW dynamic pressure was more effective during disturbed conditions. The influence of more subtle parameters like wind speed, Bz component, and proton density were masked by these dominant parameters: IMF total B, and SW dynamic pressure.

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