Average anisotropy characteristics of high energy cosmic ray particles and geomagnetic disturbance index Ap

Tiwari, C. M.; Tiwari, D. P.; Pandey, Ajay K.; Shrivastava, Pankaj

doi:10.1007/bf02702448

Cited by 4 publications

(6 citation statements)

References 6 publications

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“…The natures of variability of Galactic cosmic rays (GCR) have been studied in short term scales and long term scales [1][2][3][4], and these have revealed significant information about important processes involved in the transportation of GCR from source to the neutron monitor stations. A notable factor is solar activity [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…Many authors have studied the diurnal and semidiurnal anisotropies [2,11], annual and semiannual anisotropies [6,12], and decadal to geologic time scales of GCR flux. Cosmic rays on acceleration through the galaxy become modulated in the heliosphere by the solar wind magnetic field.…”

Section: Introductionmentioning

confidence: 99%

“…Few studies have considered modulations of cosmic rays during solar activity and using certain arrangements of geomagnetic activity level (e.g., [2]), but not much work has been done to understand the association of the solar wind parameters during different levels of interplanetary disturbance. Since a wide range of processes lead to the modulation of GCR flux on the surface of the Earth, search for dominant factors under different interplanetary conditions is needed.…”

Section: Introductionmentioning

confidence: 99%

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

Okpala

2015

Journal of Astrophysics

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The average characteristics of year-to-year variability of Galactic cosmic ray (GCR) flux measured in one mid-latitude neutron monitor stations (Newark) and high latitude station (Apatity) have been studied under different planetary disturbance (Kp) conditions. The year-to-year variability which oscillates in response to solar cycle was analyzed using Fourier technique and the amplitude of variation was obtained using data for 1980-2005. There is a noticeable trend in the difference between the amplitudes of the year-to-year variation of the two stations. The difference is highest during low Kp conditions and lowest during high Kp condition. There is generally lesser association of GCR with solar wind (SW) flow pressure and density as the Kp index increases. Similar feature is observed with the interplanetary magnetic field IMF (total). These observations have important implications for our present understanding of the effect of solar activity to variability in GCR flux.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Okpala

2015

Journal of Astrophysics

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Section: Introductionmentioning

confidence: 99%

“…The anisotropic variations in cosmic ray intensity which are observed only in the heliosphere can be easily detected by the ground based detectors [1][2][3][4][5][6]. Among the various cosmic ray intensity variations, 27-day variations, Forbush decreases and solar daily variations have been widely investigated by number of researchers [6][7][8]. The large differences in the diurnal and semi-diurnal variation of cosmic ray intensity indicate that large changes occur in interplanetary space for continuous periods, which are associated with the spatial distribution of cosmic ray intensity as well as geomagnetic disturbances.…”

Section: Introductionmentioning

confidence: 99%

Study of anisotropic variation of cosmic rays intensity with solar activity

Tiwari¹,

Sharma²,

Tiwari³

et al. 2011

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The annual average values of amplitudes and phases of first two harmonics of cosmic ray anisotropy have been derived by using the harmonic analysis technique for the period 1989 to 2004, which covers mostly the major period of solar cycles 22 and 23. In this paper we have taken the pressure corrected hourly data for Kiel neutron monitor station (cut off rigidity ≈ 2.29 GV) to derive the harmonic component of cosmic ray daily variation and compared with the data of Halekala neutron monitor (cut off rigidity ≈ 13.2 GV) for the period 1991 to 2004. From the analysis it has been concluded that the diurnal amplitude and phase of daily variation of cosmic rays have been found to be correlated with solar activity. However, the semi-diurnal amplitude and phase are inversely correlated with solar activity for both the stations

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

2015

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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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Average anisotropy characteristics of high energy cosmic ray particles and geomagnetic disturbance index Ap

Cited by 4 publications

References 6 publications

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

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

Study of anisotropic variation of cosmic rays intensity with solar activity

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

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