Correlation of MHD Waves observed at equatorial latitudes with magnitude of Interplanetary Magnetic Field

Abstract

The earth’s environment is widely affected by sun and most of the earth’s magnetospheric processes are related with the solar wind parameters. This study is carried out for a sub-group of MHD waves known as Pc4 magnetic pulsations (period range 45-150 seconds) recorded simultaneously at three very low latitude recording stations in India, viz. Pondicherry (Magnet. lat. 2.50^oN), second one Nagpur (Magnet. lat. 11.72^oN) and Hanle (Magnet. lat. 23.38^oN), which were distributed over a geomagnetic latitudinal range of about 21⁰ and its relation with interplanetary magnetic field (IMF). The relation of observed MHD wave parameters with the solar wind and parameters of IMF may become useful for theory prediction for excitation and spreading processes. The recording stations having fluxgate magnetometers were operated by IIG, Navi Mumbai, India. The work for dependence of Pc4 MHD wave’s occurrence on the strength of interplanetary magnetic field was carried out for complete year 2005. The bulk of MHD Pc4 signatures occurred with a narrow range, 2-10 nT, of IMF magnitude however its dependence spread up to 22 nT.  For the different months of whole year 2005, nearly common behavior of Pc4 events with IMF magnitude was found at each station. This study shows that peak of occurrence for IMF range 3-5 nT.