Heliospheric Modulation of Galactic Cosmic Rays during Solar Minimum of SC 23/24

Abstract

Abstract
Galactic cosmic ray (GCR) flux at earth is modulated by the heliospheric magnetic field. Heliospheric modulation potential during grand solar minimum is observed using an open solar flux (OSF) model, with OSF source based on Sunspot number. Structure of the heliosphere controls the solar outputs and their variability, and produces changes in cosmic ray intensity. Observation was based on the data taken from Omniweb data centre for solar-interplanetary data and yearly mean count rate of cosmic ray intensity (CRI) variation data from Oulu (Rc = 0.80 GV) and Moscow (Rc = 2.42 GV) neutron monitors during 1996–2016. It was observed that slow decline of solar cycle 23 and slow rise of solar cycle 24 resulted in prolonged low solar activity that lasted from about 2006 to 2009 with 2008 and 2009 being sun remarkably quiet. Therefore, solar minimum between cycle 23 and 24 was very extended and deep in contrast to previous solar minima’s and the strength of the interplanetary magnetic field (IMF) has been falling off to new low levels, reducing the GCR entering inner-heliosphere and it was high anti-correlation between sunspot number and GCR flux. The correlation between the count rate of cosmic ray intensity with solar indices and heliospheric parameters was also found.
Keywords: Interplanetary magnetic field (IMF), galactic cosmic ray intensity (GCRI), interplanetary coronal mass ejections (ICMEs), solar activity

Cite this Article
Tiwari BK, Ghormare BR. Heliospheric Modulation of Galactic Cosmic Rays During Solar Minimum of SC 23/24. Research & Reviews: Journal of Physics. 2017; 6(1): 1–4p.