The amount of solar wind produced continuously by the sun is not constant due to changes in solar activity. This unsteady nature of the solar wind seems to be responsible for galactic cosmic ray flux modulation, hence the flux of incoming galactic cosmic rays observed at the top of the Earth’s atmosphere varies with the solar wind reflecting the solar activity. The aforementioned reasons have lead to attempts by several researchers to study correlations between galactic cosmic rays and the solar wind. However, most of the correlation studies carried out by authors earlier are based on the analyses of observational data from neutron monitors. In this context, we study the effects of solar wind on galactic cosmic ray flux observed at r≈1 AU, using a theoretical approach and found that the solar wind causes significant decreases in galactic cosmic ray flux at r≈1 AU. A short time variation of the calculated flux is also checked and the result is reflected by exposing a negative correlation of the solar wind with the corresponding galactic cosmic ray flux. This means that the higher the solar wind the lower the galactic cosmic rays flux and vice-versa. To obtain a better understanding, the calculated flux and its short time variation at 1 AU are compared to data that shows a good fit to the model making it possible to establish a statistically significant negative correlation of −0.988±0.001 between solar wind variation and galactic cosmic rays flux variation theoretically.
Bibliographical noteThe authors are grateful to the following researchers and groups for their useful contributions: Barry Kellett, RAL Space, UK, H. Moraal, School of Physics, Potchefstroom University, Potchefstroom, South Africa, R.A. Caballero-Lopez, Institute for Physical Science and Technology, University of Maryland, College Park, USA, Members of the QG2 University of Aberdeen, UK, our deep appreciation goes to an honorable anonymous reviewer who’s kind and helpful suggestions were useful in developing this article and G.D.I. thanks the Nigerian tertiary education trust fund (tetfund) for financial support.
- ISM: cosmic rays
- Sun: solar wind
- Methods: analytical
- Physical data and processes: convection