The behaviour of galactic cosmic ray intensity during solar activity cycle 24

Abstract

We have studied long-term variations of galactic cosmic ray (GCR) intensity in relation to the sunspot number (SSN) during the most recent solar cycles. This study analyses the time-lag between the GCR intensity and SSN, and hysteresis plots of the GCR count rate against SSN for solar activity cycles 20-23 to validate a methodology against previous results in the literature, before applying the method to provide a timely update on the behaviour of cycle 24. Cross-plots of SSN vs GCR show a clear difference between the odd-numbered and even-numbered cycles. Linear and elliptical models have been fit to the data with the linear fit and elliptical model proving the more suitable model for even-numbered and odd-numbered solar activity cycles respectively, in agreement with previous literature. Through the application of these methods for the 24th solar activity cycle, it has been shown that cycle 24 experienced a lag of 2-4 months and follows the trend of the preceding activity cycles albeit with a slightly longer lag than previous even-numbered cycles. It has been shown through the hysteresis analysis that the linear fit is a better representative model for cycle 24, as the ellipse model doesn't show a significant improvement, which is also in agreement with previous even-numbered cycles.

arXiv comment19 pages, 10 figures, 6 tables; accepted for publication in Solar Physics

References in corpus (9)

• Observation of a Large-scale Anisotropy in the Arrival Directions of Cosmic Rays above $8\times 10^{18}$ eV
• An Updated Solar Cycle 25 Prediction with AFT: The Modern Minimum
• The 22-Year Hale Cycle in Cosmic Ray Flux - Evidence for Direct Heliospheric Modulation
• Solar cycle 24: an unusual polar field reversal
• Evidence for a Time Lag in Solar Modulation of Galactic Cosmic Rays
• Study of Cosmic-Ray Modulation during the Recent Unusual Minimum and Mini Maximum of Solar Cycle 24
• Solar Modulation of Cosmic Rays during the Declining and Minimum Phases of Solar Cycle 23: Comparison with Past Three Solar Cycles
• Signatures of Solar Cycle 25 in Subsurface Zonal Flows
• A Helioseismic Perspective on the Depth of the Minimum Between Solar Cycles 23 and 24

Cited by in corpus (13)

• Numerical modeling of cosmic rays in the heliosphere: Analysis of proton data from AMS-02 and PAMELA
• Variations of the Galactic Cosmic Rays in the Recent Solar Cycles
• The Chandra Deep Wide-Field Survey: A New Chandra Legacy Survey in the Boötes Field I. X-ray Point Source Catalog, Number Counts and Multi-Wavelength Counterparts
• Cosmic Ray Intensity Variation Lags Sunspot number: Implications of Late Opening of Solar Magnetic Field
• Temporal evolution and rigidity dependence of the solar modulation lag of Galactic cosmic rays
• The exoplanetary magnetosphere extension in Sun-like stars based on the solar wind -- solar UV relation
• On the time lag between solar wind dynamic parameters and solar activity UV proxies
• The Sun's magnetic (Hale) cycle and 27 day recurrences in the $aa$ geomagnetic index
• Galactic Cosmic Rays at Mars and Venus: Temporal Variations from Hours to Decades Measured as the Background Signal of Onboard Micro-Channel Plates
• Deep Learning the Forecast of Galactic Cosmic-Ray Spectra
• Scaler rates from the Pierre Auger Observatory: a new proxy of solar activity
• The Instantaneous Response of Geomagnetic Field, near-Earth IMF and Cosmic-Ray Intensity to Solar Flares
• Extracting Hale Cycle Related Components from Cosmic-Ray Data Using Principal Component Analysis