Geomagnetic Field Disturbances with Solar Features and Solar Wind Plasma Parameters During The Period of 2009–2012

We have studied geomagnetic storms (Dst ≤ 80nT) observed during the period of 2009-2012, with halo and partial halo coronal mass ejections ,X-ray solar flares ,interplanetary shocks and disturbances in solar wind plasma parameters . We have found that 81.25% geomagnetic storms are associated with halo and partial halo coronal mass ejections. The association rate of geomagnetic storms with halo and partial halo coronal mass ejections are found 61.54% and 38.46% respectively. We have found positive correlation with correlation coefficient 0.69 between magnitude of geomagnetic storms and speed of associated CMEs. Further we have observed that geomagnetic storms are also associated with X ray solar flares of different categories. The association rate of B-class, C-class and M-class X-ray solar flares are found 20.00%, 40.00% and 40.7% respectively. Majority of the geomagnetic storms 68.75% have been found to be associated with interplanetary shocks . From the study of geomagnetic storms with storms in solar wind plasma parameters we have determined positive co-relation between magnitude of geomagnetic storms and peak values of associated storm in solar wind plasma parameters with co-relation co-efficient, 0.72 between magnitude of geomagnetic storms and peak values of associated storms in interplanetary magnetic field, 0.28 between magnitude of geomagnetic storms and peak value of associated solar wind plasma temperature, 0.24 between magnitude of geomagnetic storms and peak value of associated solar wind plasma pressure. Omkar Prasad Tripathi P. L. Verma Research Scholar Govt.P.G.College Maihar Satna M.P.India Department of Physics Govt.Vivekanand P.G.College Maihar Satna M.P.India. Govt.Vivekanand P.G.College, Maihar Satna, M.P., India 1-Introduction The physical condition on the sun and in the heliosphere responsible for the production of appreciable geo-magnetic perturbations is still under investigation. They are commonly related to powerful non stationary process on the time scale from less than one hour to many hours in the solar corona and deeper layers of the solar atmosphere. It is generally believed that geomagnetic perturbations are produced by heliospheric magnetic fields and solar wind plasma streams related to the active regions, disappearing filaments and prominences, solar flares, coronal mass ejections (CMEs) and coronal holes (CH), and heliospheric current sheet (HCS). Impulsive and long duration solar flares, disappearing filaments, CMEs transient brightening and coronal holes, are the most popular solar signatures to date used for the study of geomagnetic storms . Since the beginning of the space age, the cause of geomagnetic activity has been sought in a number of correlative studies (Akasofu 1983). It is suggested that geomagnetic, activity is related to variety of interplanetary plasma/ field parameters, e.g. Solar wind velocity V, interplanetary magnetic field (IMF) B and Bz (Akasofu 1983, Joselyn and McIntosh1981,Gonzalez,et al 1994). Furthermore, the strong geomagnetic disturbance is associated with passage of magnetic cloud (Gonzalez, 1994), which causes intense and severe geomagnetic storms. (Weigel 2010). Wu & Lepping (2006) have investigated geomagnetic activity induced by interplanetary magnetic cloud (MC) during the past four solar cycles, 1965~1998 and found that the intensity of geomagnetic storms is more severe in a solar active period than in a solar quiet period. Borovsky & Denton (2006) have studied the coronal mass ejection (CME)-driven storms and co-rotating interaction region (CIR)-driven geomagnetic storms and showed that there are many differences between coronal mass ejection (CME)-driven storms and co-rotating interaction region (CIR)-driven storms. According to their findings, CME-driven storms have denser plasma sheets, stronger ring currents, disturbance storm time (Dst) perturbation, and solar energetic particle events, while CIR-driven storms have longer duration and hotter plasma sheets. On the other hand, many studies have examined the role of solar wind parameters in the development of geomagnetic storms. Some other scientists have reported that the properties of the earth-directed CMEs, such as the internal structure of the magnetic field, may determine whether or not a geomagnetic storm subsequently occurs (Burton et al. 1975; Cane et al.2000). Some other scientists have associated geomagnetic storms with coronal mass ejections (Caneet al., 2000; Cane and Richardson, 2003; Gopalswamy et al., 2007; Gopalswamy et al., 2007; Howard et al., 1982; St. Cyr et al., 2000; Webb et al., 2000; Zhao and Webb, 2003; Zhang et al., 2007,verma 2012) and all found good associations between front side halo CMEs and geomagnetic storms. Tsurutani (2001) concluded that that major geomagnetic storms are caused by solar wind structures that possess strong (>> 5 nT) southward components of the interplanetary magnetic field at 1 AU, which are usually, but not always at wind speeds higher than average. Gopalswamy (2009) studied geo-effectiveness of halo and partial halo coronal mass ejections and concluded that the geoeffectiveness of partial halo CMEs is lower because they are of low speed and likely to make a glancing impact on the Earth. Rather than halo coronal mass ejections. Michalek et al. (2005) concluded that halo coronal mass ejections (HCMEs) originating from regions close to the center of the sun are likely to be geoeffective. They have showed that only fast halo CMEs (with space velocities higher than ~1000 km/s) and originating from the western hemisphere close to the solar center could cause intense geomagnetic storms. In this investigation we have studied geomagnetic storms (Dst ≤ 80nT) observed during the period of 2009-2012 with coronal mass ejections X-ray solar flares and disturbances in solar wind plasma temperature, pressure and interplanetary magnetic fields to know the role of these parameters to generate geomagnetic storms.