Coronal Mass Ejections, Interplanetary Shocks In Relation With Forbush Decreases Associated With Intense Geomagnetic Storms

15th International Congress on Plasma Physics; 13th Latin American Workshop on Plasma Physics

Verma, P.L.^1 ; Patel, Nand Kumar^2 ; Prajapati, Mateswari^3

Department of Physics, Govt. Vivekanand P.G. College, Maihar, Satna, M.P., India^1

A.P.S. University, Rewa, M.P., India^2

Govt. P.G. College, Satna, M.P., India^3

关键词: Association rates;    Coronal mass ejection;    Cosmic ray intensity;    Geomagnetic storm;    Intense geomagnetic storms;    Interplanetary shocks;    Neutron monitors;    Solar wind plasmas;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/511/1/012057/pdf
DOI  :  10.1088/1742-6596/511/1/012057

来源: IOP

【 摘 要 】

Coronal mass ejections (CMEs} are the most energetic solar events in which large amount of solar plasma materials are ejected from the sun into heliosphere, causing major disturbances in solar wind plasma, Interplanetary shocks, Forbush decrease(Fds) in cosmic ray intensity and geomagnetic storms. We have studied Forbush decreases associated with intense geomagnetic storms observed at Oulu super neutron monitor, during the period of May 1998-Dec 2006 with coronal mass ejections (CMEs), X-ray solar flares and interplanetary shocks. We have found that all the (100%) Forbush decreases associated with intense geomagnetic storms are associated with halo and partial halo coronal mass ejections (CMEs). The association rate between halo and partial halo coronal mass ejections are found 96.00%and 04.00% respectively. Most of the Forbush decreases associated with intense geomagnetic storms (96.29%) are associated with X-ray solar flares of different categories . The association rates for X-Class, M-Class, and C- Class X -ray solar flares are found 34.62%, 50.00% and 15.38% respectively .Further we have concluded that majority of the Forbush decrease associated with intense geomagnetic storms are related to interplanetary shocks (92.30 %) and the related shocks are forward shocks. We have found positive co-relation with co-relation co-efficient .7025 between magnitudes of Forbush decreases associated with intense geomagnetic storms and speed of associated coronal mass ejections. Positive co-relation with co-relation co-efficient 0.48 has also been found between magnitudes of intense geomagnetic storms and speed of associated coronal mass ejections.