Galactic Cosmic Ray Variability at Two Neutron Monitors: Relation to Kp Index

Okpala, Kingsley Chukwudi

doi:10.1155/2015/961358

Cited by 2 publications

(1 citation statement)

References 14 publications

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“…These particles have varying degree of influence on spacecrafts and aircrafts (Mavromichalaki et al, 2007). Rapid and slow time changes of GCRs have been studied my many authors (Forbush, 1937(Forbush, , 1957Cane, 2000;Richards, 2004;Firoz, 2008;Okpala and Okeke, 2011;Desorgher et al, 2013;Okpala, 2014). Forbush (1937 observed a world-wide decreases in GCR during a strong geomagnetic storm (Forbush decrease) giving the first evidence for a relationship between solar activity and GCRs.…”

Section: Introductionmentioning

confidence: 99%

On the slow-time geomagnetic field modulation of cosmic rays

Friday¹,

Chukwudi²

2019

Int. J. Phys. Sci.

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In this work, monthly means of cosmic ray count rates from two mid latitude (Hermanus and Rome), and two higher latitude (Inuvik and Oulu) neutron monitors (NM) were employed and their variability was compared with geomagnetic stations that are in close proximity to the NMs. The data spans 1966 to 2008 and covers four solar cycles. The difference (CRdiff) between the mean count rate of all days and the mean of the five quietest days for each month was compared with the Dst-related disturbance (Hdiff) derived from the nearby geomagnetic stations. Zeroth-and First-correlation between the cosmic ray parameters and geomagnetic parameters was performed to ascertain statistical association and test for spurious association. The present results show that solar activity is generally strongly correlated (>0.75) with mean strength of GCR count rate and geomagnetic field during individual solar cycles. The correlation between mean strength of cosmic ray intensity and geomagnetic field strength is spurious and is basically moderated by the solar activity. The signature of convection driven disturbances at high latitude geomagnetic stations was evident during the declining phase of the solar cycles close to the solar minimums. The absence of this feature in the slow-time varying cosmic ray count rates in all stations and in the mid latitude geomagnetic stations suggests that the local geomagnetic disturbance do not play a significant role in modulating the cosmic ray flux.

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Section: Introductionmentioning

confidence: 99%

On the slow-time geomagnetic field modulation of cosmic rays

Friday¹,

Chukwudi²

2019

Int. J. Phys. Sci.

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An evaluation of space weather conditions for FORMOSAT-3 satellite anomalies

Shen

Shue

Dombeck

et al. 2021

Earth Planets Space

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The variable electromagnetic environment in geospace plays a crucial role in influencing the occurrence probability of satellite anomalies. FORMOSAT-3 (FS3) is a Low-Earth-Orbit (LEO) mission, which consists of six identical microsatellites that orbit in the altitude of 700–800 km and with an inclination of 72°. The dependences of the FS3 satellite anomalies on space weather conditions have not been investigated in the past. With an exception of a small number of extremely high geomagnetic events, we find that the occurrence rate of the FS3 anomalies is negatively correlated with the level of geomagnetic activity. Moreover, the relationship between numbers of anomalies and sunspots is also anti-correlated. A superposed epoch analysis demonstrates that the intensity of galactic cosmic rays (GCR) is relatively high at the times of the anomalies. All these results infer that the FS3 anomalies predominantly occurred under the conditions associated with low solar activity. The possible main cause for the FS3 anomalies is high-energy trapped protons or GCR. In summary, this paper presents a statistical result that a satellite can be prone to suffer an anomaly under low solar or geomagnetic activity.

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Galactic Cosmic Ray Variability at Two Neutron Monitors: Relation to Kp Index

Cited by 2 publications

References 14 publications

On the slow-time geomagnetic field modulation of cosmic rays

On the slow-time geomagnetic field modulation of cosmic rays

An evaluation of space weather conditions for FORMOSAT-3 satellite anomalies

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