Characteristics of high energy cosmic ray diurnal anisotropy on day-to-day basis

Tiwari, C. M.; Tiwari, D. P.

doi:10.1134/s0010952508050134

Cited by 5 publications

(4 citation statements)

References 6 publications

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“…A number of investigators have reported the short-term characteristics of the daily variation, where they have selected continually occurring days of high and low amplitudes of diurnal variation (Tiwari, 1994;Agrawal et al, 1974, Tiwari, 1995. These results have pointed out significant departures in the time of maximum as well as their association with higher harmonics.…”

Section: Introductionmentioning

confidence: 84%

“…Special type of consecutive days having abnormally high or low amplitudes in daily variation of cosmic rays have been reported several times earlier with explanation of sources and sinks in anti-garden-hose and garden-hose directions (Jadhav et al, 1983;Rao et al, 1972;Tiwari, 1994). The existence of high and low amplitude anisotropic wave trains have been revealed through the long-term study of cosmic ray intensity.…”

Section: Introductionmentioning

confidence: 99%

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Modulation of cosmic rays at different cutoff rigidity

Agarwal

Mishra

2008

Braz. J. Phys.

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The present work deals with the study of first three harmonics of cosmic ray intensity on geo-magnetically quiet days over the period [1981][1982][1983][1984][1985][1986][1987][1988][1989][1990][1991][1992][1993] for Deep River and Inuvik neutron monitoring stations having mid and low cutoff rigidity. The amplitude of first harmonic remains high for Deep River having mid cutoff rigidity as compared to Inuvik neutron monitor having low cutoff rigidity on quiet days. The diurnal amplitude significantly decreases and phase shifts towards an earlier time during solar activity minimum years at both Deep River and Inuvik. The amplitude of second harmonic significantly enhanced during solar activity minimum as well as maximum at Deep River and remains low during solar activity maximum at Inuvik, whereas the phase shifts towards an earlier time during solar maximum for both the stations. The amplitude of the third harmonic significantly enhanced during solar activity minimum at Deep River and on solar activity minimum at Inuvik, whereas the phase does not show any significant characteristics and fluctuates quite frequently. The amplitude of semi/tri-diurnal anisotropy has a good positive correlation, while the others (i.e. amplitude and phase) have very weak correlation with solar wind velocity on quiet days at Deep River station during 1981-1993. The solar wind velocity significantly remains in the range 350 to 425 km/s i.e. being nearly average on quiet days. The amplitude and direction of the anisotropy on quiet days are weakly dependent on high-speed solar wind streams for two neutron monitoring station of mid and low cutoff rigidity threshold. The amplitude as well as direction of second harmonic has a good anti-correlation with IMF Bz and the product V x Bz on quiet days at Deep River station. However, the direction of second and third harmonic has a good anti-correlation with IMF Bz and the product V x Bz on quiet days at Inuvik station.

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Section: Introductionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Modulation of cosmic rays at different cutoff rigidity

Agarwal

Mishra

2008

Braz. J. Phys.

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“…On the other hand, muons can create a considerable highenergy background for larger area detectors like PVTs (see section 4.4) when used for detecting neutroninduced high-energy gamma-rays [3]. For such detectors, diurnal variation of muon rates, cosmic neutrons and cosmic-induced gamma-rays ( [3], [18], [19]) should be considered for a complete characterization of the background in the high-energy region [3], [15].…”

Section: Cosmogenic Sourcesmentioning

confidence: 99%

Field Response Prediction: Framing the problem.

Cabrera-Palmer

2017

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“…The occurrence of the phase at stations with lower cut-off rigidity is considerably influenced by the drift effect, which is determined by the reversal of the polarity of the solar magnetic field, as mentioned by (Sabbah, 2013). The research conducted by (Tiwari et al, 2005) documented a significant phase shift towards earlier hours starting in 1995, which was particularly evident in 1996 and 1997. This shift is more pronounced at lower latitudes than at higher or mid-latitudes.…”

Section: Introductionmentioning

confidence: 97%

Decades of Diurnal Anisotropy: Unravelling the Time of Maximum of Diurnal Anisotropy

Gautam,

Dubey

2024

eatp

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The diurnal anisotropy in cosmic ray intensity has been the subject of continuous observation and study over the past seven decades. This phenomenon is characterised by diurnal variations in the direction of arrival of cosmic rays and plays an important role in the spatial distribution and propagation mechanism of these high-energy particles. The time of maximum of diurnal anisotropy, which is a key parameter in understanding the fundamental process, has displayed variations that have been attracting researchers for years. This study used 60 years of neutron monitor data to analyse the phase diurnal anisotropy of the cosmic ray flux. The data were collected from the Inuvik and Moscow neutron monitor stations and analysed using the Fourier analysis method. The dataset spanned six decades and was used to identify anisotropic patterns. The results showed that the phase of diurnal variability changed slightly between the A>0 and A<0 polarity epochs, indicating a shift in the anisotropy of the cosmic ray flux arriving at the Earth. During 2019-20, the phase of diurnal anisotropy shifted towards the early hours. This study aimed to better understand these temporal variations.

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Characteristics of high energy cosmic ray diurnal anisotropy on day-to-day basis

Cited by 5 publications

References 6 publications

Modulation of cosmic rays at different cutoff rigidity

Modulation of cosmic rays at different cutoff rigidity

Field Response Prediction: Framing the problem.

Decades of Diurnal Anisotropy: Unravelling the Time of Maximum of Diurnal Anisotropy

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