Abstract Details
| Name: Bhupendra Kumar Tiwari Affiliation: A.P.S. University Rewa M.P. Conference ID: ASI2016_422 Title : Heliospheric Modulation of Galactic Cosmic Rays during Solar Minimum of solar cycle 23/24 Authors and Co-Authors : B.K.Tiwari Department of Physics A.P.S.University, Rewa (M.P.)INDIA Abstract Type : Poster Abstract Category : Sun and the Solar System Abstract : Heliospheric Modulation of Galactic Cosmic Rays during Solar Minimum of solar cycle 23/24 B. K. Tiwari Department of Physics, A. P. S. University, Rewa (M.P.), btiwari70@yahoo.com Galactic cosmic rays (GCRs) flux at earth is modulated by the heliosphereric magnetic field and the structure of the heliosphere, controls by solar outputs and their variability. Sunspots numbers (SSN) is often treated as a primary indicator and 10.7 cm solar radio flux are an important gauge of solar activity (SA). GCRs entering the helioshphere are affected by the interplanetary magnetic field (IMF) and solar wind speed, their modulation varies with the varying solar activity. The observation based on data recoded from Omniweb data Centre for solar- interplanetary activity indices and monthly mean count rate of cosmic ray intensity (CRI) data from neutron monitors of different cut-off rigidities(Rc) (Moscow Rc=2.42GV and Oulu Rc=0.80GV). During minimum solar activity period of solar cycle 23/24, the sun is remarkably quiet, weakest strength of the IMF and least dense and slowest, solar wind speed, whereas, in 2003, highest value of yearly averaged solar wind speed (~568 Km/sec) associated with several coronal holes, which generate high speed wind stream has been recorded. It is observed that GCRs fluxes reduces and is high anti-correlated with SSN (0.80) and IMF (0.86). Modulation in CRI produces by a strong solar flare, however, CME associated solar flare produce more disturbance in the interplanetary medium as well as in geomagnetic field. It is found that count rate of cosmic ray intensity and solar- interplanetary parameters were inverse correlated and solar indices were positive correlated. Keywords- Galactic Cosmic rays (GCRs), Sunspot number (SSN), Solar activity (SA), Coronal Mass Ejection (CME), Interplanetary magnetic field (IMF) |