Respuesta de la ionosfera en latitudes medias a tempestades geomagnéticas intensas

Abstract

It is presented an analysis of the mid-latitude ionospheric response to geomagnetic storms using digisonde observations. The the ionospheric behavior for the strongest storms of 2003-2005 has been analyzed making use of the electron density profiles and main ionospheric characteristics foF2 and hmF2. The observed pattern for most of the storms suggests that the main driver of the ionospheric response is the neutral wind dynamics which generates a composition change bulge in the upper atmosphere. The local time dependence of the ionospheric effects supports a possibility of this mechanism as well. There is also experimental evidence that the Traveling Atmospheric Disturbances (TADs) play significant role in the daytime effects. Digisonde measurements demonstrate a systematic uplifting of the ionosphere during storms. The delay between the storm commencement and the beginning of the ionospheric uplifting is consistent with the effect of ionospheric disturbances originating in the auroral oval and propagating equatorward with the speed of a few hundred meters per second. The observed longer delay in the start of the uplifting for the stations located at lower latitudes is in agreement with such picture.