Cosmic ray intensity variation with solar flare index, solar coronal index and sunspot numbers solar indices during the period of 1986-2007


It has been known for a long time that the cosmic ray intensity variations are directly related to changes in different solar activity parameters such as sunspot numbers (SSN), solar flux (SF, 10.7 cm), solar flare and grouped solar flares (GSF), solar flare index (SFI), solar coronal index (SCI), and tilt angle (TA),In present investigation we have analyzed  yearly mean value data of sunspot numbers (SSN) solar flare index (SFI)solar coronal index (SCI) and yearly mean values  of cosmic ray count rate observed during the period of 1986-2007 to investigate the possible relationship between cosmic ray variation with solar flare index(SFI) and solar coronal index (SCI) .We have observed that  yearly mean of cosmic ray intensity is anti-correlated with yearly mean of solar flare index (SFI) , sunspot number(SSN)  and solar coronal index (SCI).Further the solar parameters solar flare index, sunspot number and coronal index is positively correlated with cosmic ray intensity .Large negative correlation with correlation coefficient  -0.76 has been determined between yearly mean value of solar flare index and cosmic ray intensity,-0.89 between yearly mean value of sunspot number and cosmic ray intensity and -0.85 between yearly mean value of coronal index and cosmic ray intensity. Further large positive correlation with correlation coefficient 0.93 has been determined between solar flare index (SFI) and sunspot number (SSN), 0.96 between solar flare index (SFI) and solar coronal index (SCI) and 0.97 between sunspot number (SSN) and solar coronal index (SCI).It is concluded that cosmic ray intensity is highly influences by solar activity parameters solar flare index (SFI) sunspot numbers (SSN) and solar coronal index (SCI).

Keyword: – Sunspot numbers (SSN), Solar flare index (SFI), solar coronal index (SCI) Cosmic ray intensity (CRI).

Rooplata Chaturvedi1, Jaypal Singh Lodhi2, Surendra Kumar Khandayat3, Chitranshi Tiwari4, P. L. Verma5*, Amit Kumar Nigam6