Effects of two types of solar wind streams on intensity variations of cosmic rays

Yadav, Ravi; Sharma, N. K.; Badruddin,

doi:10.1007/bf00679085

Cited by 9 publications

(4 citation statements)

References 6 publications

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“…When A < 0, the global effects of hybrid field are almost negligible. Their model predictions are consistent with the observed results (Zhang 1997;Paizis et al 1999) only when drift effects are included, indicating that drifts are important for corotating modulation.…”

supporting

confidence: 87%

“…Corotating depressions in cosmic rays have been studied in relation to solar wind plasma and field conditions (e.g. Barouch and Burlaga 1975;Duggal and Pomerantz 1977;Iucci et al 1979;Scholar et al 1979;Duggal et al 1981;Venkatesan et al 1982;Burlaga et al 1984;Mishra et al 1990;Badruddin 1993Badruddin , 1997Yadav et al 1994;Richardson et al 1996Richardson et al , 1999Sabbah 2000b;Gil et al 2005;Gupta and Badruddin 2005;Singh and Badruddin 2007; see reviews by Venkatesan and Badruddin 1990;Simpson 1998;Mckibben et al 1999;Richardson 2004). However, consensus eludes the conclusion as regards the solar wind parameters playing important role in these depressions; probably due to near simultaneous variations in a number of parameters (e.g., solar wind velocity, magnetic field magnitude, magnetic turbulence etc.)…”

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confidence: 98%

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Solar magnetic cycle dependence in corotating modulation of galactic cosmic rays

Gupta

Badruddin

2009

Astrophys Space Sci

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We study the temporal evolution of cosmic ray intensity during ∼27-day Carrington rotation periods applying the method of superposed epoch analysis. We discuss about the average oscillations in the galactic cosmic ray intensity, as observed by ground based neutron monitors, during the course of Carrington rotation in low solar activity conditions and in different polarity states of the heliosphere (A < 0 and A > 0). During minimum and decreasing phases in low solar activity conditions, we compare the oscillation in one polarity state with that observed in other polarity state in similar phases of solar activity. We find difference in the evolution and amplitude of ∼27-day variation during A < 0 and A > 0 epoch. We also compare the average variations in cosmic ray intensity with the simultaneous variations of solar wind parameters such as solar wind speed and interplanetary magnetic field strength. From the correlation analysis between the cosmic ray intensity and the solar wind speed during the course of Carrington rotation, we find that the correlation is stronger for A > 0 than A < 0.

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confidence: 87%

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confidence: 98%

Solar magnetic cycle dependence in corotating modulation of galactic cosmic rays

Gupta

Badruddin

2009

Astrophys Space Sci

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“…Previous studies of cosmic ray depressions due to corotating high‐speed streams [e.g., Duggal and Pomerantz , 1977; Iucci et al , 1979; Venkatesan et al , 1982; Burlaga et al , 1984; Mishra et al , 1990; Badruddin , 1993, 1997; Yadav et al , 1994; Richardson et al , 1996, 1999; Alania et al , 2001; Gil et al , 2005] have reached at different and sometimes even conflicting conclusions, probably due to near simultaneous variations in a number of parameters (e.g., solar wind speed, magnetic field fluctuations, and magnitude) within a stream. As a consequence of variations in these parameters, several processes could contribute in recurrent cosmic ray modulation.…”

Section: Introductionmentioning

confidence: 99%

“…Recurrent cosmic ray modulation due to CIRs and high‐speed streams have been studied using ground‐based neutron monitors and spacecraft data [e.g., Vershell et al , 1975; Parker , 1976; Shah et al , 1978; Iucci et al , 1979; Duggal et al , 1981; Venkatesan et al , 1982; Tiwari et al , 1983; Burlaga et al , 1984; Mishra et al , 1990; Yadav et al , 1994; Shrivastava and Shukla , 1994; Kunow et al , 1995; Richardson et al , 1996, 1999; Badruddin , 1997; Zhang , 1997; Paizis et al , 1999; Alania et al , 2001; Reames and Ng , 2001; Gil et al , 2005, Gupta and Badruddin , 2005; Singh and Badruddin , 2005; Venkatesan and Badruddin , 1990; Simpson , 1998; McKibben et al , 1999; Richardson , 2004]. However, such depressions in cosmic ray intensity have been associated with enhanced convection by high‐speed solar wind [ Newkirk and Fisk , 1985; Iucci et al , 1979; Richardson et al , 1996], diffusion in enhanced/compressed field region [ Burlaga et al , 1984; Kota and Jokipii , 1991], and/or particle drifts in large‐scale heliospheric magnetic field [ Kota and Jokipii , 1991, 2001; Burger and Hitge , 2004].…”

Section: Introductionmentioning

confidence: 99%

Corotating high‐speed solar‐wind streams and recurrent cosmic ray modulation

Singh

Badruddin

2007

J. Geophys. Res.

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[1] We studied the solar magnetic cycle dependence of cosmic ray depressions due to the corotating high-speed solar wind streams (CSWS) during different polarity states of the heliosphere. The daily averaged cosmic ray intensity data from Climax, Oulu, and Thule neutron monitors together with simultaneous solar wind plasma and field data were subjected to the superposed epoch analysis with respect to CSWS start time. These analyses were carried out separately in different polarity states of the heliosphere A < 0 and A > 0 during solar minimum as well as during the periods of variable solar activity. Although the average variations in the solar wind velocity, IMF strength, and its variance are almost similar, the amplitudes of CSWS-associated cosmic ray depressions are quite different during different polarity epochs; they are larger during A > 0 than A < 0 periods. Further, correlation analysis between cosmic ray intensity and solar wind velocity during CSWS shows differences in their relationship during A > 0 and A < 0; they are much better during A > 0 than A < 0. Two other solar wind parameters, IMF strength and its variance, do not show a significant relationship with cosmic ray intensity change through the passage of these streams, although the initial depression coincides the enhancement of the two parameters. These results are discussed in the light of existing models of galactic cosmic ray modulation.Citation: Singh, Y. P., and Badruddin (2007), Corotating high-speed solar-wind streams and recurrent cosmic ray modulation,

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Cosmic ray modulation: Effects of high speed solar wind streams

Badruddin

1996

Astrophys Space Sci

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Effects of two types of solar wind streams on intensity variations of cosmic rays

Cited by 9 publications

References 6 publications

Solar magnetic cycle dependence in corotating modulation of galactic cosmic rays

Solar magnetic cycle dependence in corotating modulation of galactic cosmic rays

Corotating high‐speed solar‐wind streams and recurrent cosmic ray modulation

Cosmic ray modulation: Effects of high speed solar wind streams

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