Afternoon mid-latitude current system and low-latitude geomagnetic field asymmetry during geomagnetic storms

摘要

For four geomagnetic storms of middleintensity the relationship between the low-latitude magnetic field asymmetryusing ASY indices and the intensity of the auroral eastward and westwardelectrojet was considered. It was asked whether there exists a connectionbetween ASY and the eastward electrojet. To answer this question equivalentcurrent systems were estimated in mid-latitudes. It was found that theobservations obviously show no correlative relationship between the low-latitudemagnetic-field asymmetry and the eastward electrojet, whereas one exists betweenASY and the westward electrojet. To explain the generally accepted commonthree-dimensional current system between the partial ring current and theeastward electrojet, a condensor model of the three-dimensional current systemwas developed. It could be shown that the short periodic variations of thepartial ring current are shielded by the condensor and cannot influence theeastward-electrojet current.