Modulation of Galactic Cosmic Rays Due to Magnetic Clouds and Associated Structures in the Interplanetary Space: 1996-2018

Fadaaq, M.; Badruddin, B.

doi:10.1007/s10511-021-09682-3

Cited by 4 publications

(1 citation statement)

References 32 publications

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“…The seed flux rope can be hot [208] or cold (associated with a filament) [209,210]. We have also not discussed another aspect of CMEs and CIRs, viz., the Forbush decrease (see [211][212][213] and references therein), nor the overall increase in cosmic ray flux due to weak solar activity [214].…”

Section: Discussionmentioning

confidence: 99%

The Sun and Space Weather

Gopalswamy

2022

Atmosphere

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The explosion of space weather research since the early 1990s has been partly fueled by the unprecedented, uniform, and extended observations of solar disturbances from space- and ground-based instruments. Coronal mass ejections (CMEs) from closed magnetic field regions and high-speed streams (HSS) from open-field regions on the Sun account for most of the disturbances relevant to space weather. The main consequences of CMEs and HSS are their ability to cause geomagnetic storms and accelerate particles. Particles accelerated by CME-driven shocks can pose danger to humans and their technological structures in space. Geomagnetic storms produced by CMEs and HSS-related stream interaction regions also result in particle energization inside the magnetosphere that can have severe impact on satellites operating in the magnetosphere. Solar flares are another aspect of solar magnetic energy release, mostly characterized by the sudden enhancement in electromagnetic emission at various wavelengths—from radio waves to gamma-rays. Flares are responsible for the sudden ionospheric disturbances and prompt perturbation of Earth’s magnetic field known as magnetic crochet. Nonthermal electrons accelerated during flares can emit intense microwave radiation that can drown spacecraft and radar signals. This review article summarizes major milestones in understanding the connection between solar variability and space weather.

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Section: Discussionmentioning

confidence: 99%

The Sun and Space Weather

Gopalswamy

2022

Atmosphere

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Behaviour of 27-Day and 13.5-Day Periodicities in Galactic Cosmic Particles as Observed by Spacecraft and Neutron Monitors During Different Solar Polarity Cycles

Kotzé

2023

Sol Phys

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An analysis has been made of the behaviour of the 27-day and 13.5-day periodicities in proton, C, and O galactic-cosmic-ray (GCR) particles at different energies as observed by the Advanced Composition Explorer (ACE) and SOHO (Solar and Heliospheric Observatory) spacecraft during both Solar Cycles 23 and 24. In addition, the behaviour of the 27-day and 13.5-day periods in the solar-wind-modulation parameter $\zeta $ ζ = BIMF × VSW has been investigated during the same time interval to determine the existence of a possible solar-polarity dependence. Ground-based neutron-monitor (NM) observations, corresponding to different rigidity cutoff [RC] parameters, were also studied to determine the temporal behaviour of both the 27-day and 13.5-day periods during Cycles 23 and 24, revealing a statistically significant solar-polarity correlation. The Lomb–Scargle periodogram technique has been employed to extract spectral information from the above-mentioned observations for each individual year from 2001 – 2009 (Cycle 23) and 2010 – 2019 (Cycle 24). Daily mean energetic ACE and SOHO particle measurements are used to identify how both the 27-day and 13.5-day periodicities vary during each individual year during these cycles as a function of particle mean energy. This spectral analysis of proton, C, and O galactic-cosmic-particle data at different energies revealed that both the 27-day and 13.5-day periods are stronger during the minimum of Solar Cycle 24/25 when A > 0 (solar dipole pointing North) in comparison to the minimum of Cycle 23/24 when A < 0 (solar dipole pointing South) at certain energy levels. This showed a particularly strong energy-dependent behaviour for both periodicities. This article reports for the first time an annual time- and energy-dependent behaviour of both the 27-day and 13.5-day periodicities in daily-mean galactic cosmic particles observed by spacecraft and ground-based neutron monitors during consecutive Solar Cycles 23 and 24, corresponding to opposite solar-magnetic-field orientations. Periodicity behaviour in heliospheric solar-wind data corroborate these results in general.

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