Study of long-term cosmic ray intensity variation with sunspot numbers, solar flare index, interplanetary magnetic fields and Alfven Mach number during solar cycle 24

Abstract  

We have studied yearly average values of cosmic ray intensity observed at Kiel super neutron monitor with yearly average values of sunspot numbers (SSN) ,yearly average values of solar flare index (SFI),yearly average values of interplanetary magnetic fields (IMF) and yearly average values of Alfven Mach number during the period of solar cycle 24 and it is observed that yearly average values of cosmic ray intensity are anticorrelated with yearly average values of sunspot numbers (SSN) and yearly average values of solar flare index (SFI). Large negative correlation with correlation coefficient -0.80 has been found between yearly average values of cosmic ray intensity variation and yearly average of sunspot numbers and large negative correlation with correlation coefficient -0.78 has been found between yearly average values of cosmic ray intensity variation and yearly average values of solar flare index. we have also obtained negative correlation with correlation coefficient -0.49 between yearly average values of cosmic ray intensity variation and yearly average values of interplanetary magnetic fields. Further it is seen that yearly average values of cosmic ray intensity are positively correlated with yearly average values of Alfven Mach number. We have determined large positive correlation with correlation coefficient 0.81 between yearly average values of cosmic ray intensity variation yearly average values of Alfven Mach number.

Keywords: – Cosmic ray intensity (CRI), Sunspot number (SSN), Solar flare index (SFI), Interplanetary magnetic fields (IMF) and Alfven Mach number.

Rooplata Chaturvedi1*, Amit Nigam2, Sunil Kumar Khandayat3