Structure of auroral zone phenomena from the data of meridional chains of stations: magnetic disturbances in the nighttime auroral zone and auroras

Abstract

A new method of compulation of the equivalent currents using meridional chain stations' magnetic data is proposed to study the auroral electrojet structure. The correctness and resolving power of the method are estimated by test calculations. On the basis of computer simulation studies, it is shown that the method may be applied in practice when variations in the geomagnetic H-components are sufficiently larger than those in the D-component. Using the method, a fine structure of the westward electrojet was found. This structure is the same at two longitudinally separated meridians (in Scandinavia and the Kola peninsula) and seems to be associated with auroral features. The conclusion is made that the small-scale field-aligned and ionospheric currents with a width of less than 0.5 are not displayed in magnetic observations made on the ground against the effects of larger-scale structures.