1. Department of Physics, Rishi Bankim Chandra College, Naihati, W.B. 743165, India
2. Indian Centre for Space Physics, Kolkata 700084, India
3. Sun Yat-sen University, 135 West Xingang Road, Guangzhou 510275, China
4. S. N. Bose National Centre For Basic Sciences, Kolkata 700098, India