Diagnostics of the Ionospheric Conductivity Based on Spacecraft Observations of the Magnetospheric ULF Waves

摘要

In 27 October 2012 an Alfven wave of the Pc4 range was observed with Van Allen Probe A. The parallel Poynting flux of the wave was directed toward the Northern ionosphere. Assuming that this may be caused by the asymmetry of the ionospheric conductivity between the Northern and Southern hemispheres, its effect on the standing structure of the Alfven wave was investigated. For this purpose, the analytical model with straight magnetic field lines was used. As a result, the method for estimation of the Northern and Southern ionospheric conductivity was developed. It allows to reconstruct the parallel structure of Alfven waves under various conditions of the ionospheric conductivity. With the method developed, the ionospheric conductivity for the 27 October 2012 event was evaluated and compared with ionosphere model IRI-2016 results.