An investigation of ionospheric disturbances over the north-eastern region of Russia in October 2003 using auroral images and data from a network of ground-based instruments

This paper presents the results of analyzing the experimental data from the Irkutsk incoherent scatter radar, GPS receiver in Yakutsk, digital ionosounders for vertical- and oblique-incidence sounding combined with auroral images during geomagnetic disturbances as a consequence of high flaring activity of the Sun from 19 to 29 of October, 2003. Overall the observations can be interpreted in terms of the thermosphere storm model and main ionospheric trough motion. At once the negative critical frequency disturbance observed during the major storm on October 29 can not be explained in terms of the noted models.