Midlatitude ionospheric F2-layer response to eruptive solar events-caused geomagnetic disturbances over Hungary during the maximum of the solar cycle 24: a case study

TL;DR

This case study investigates how geomagnetic storms during solar cycle 24 affected the midlatitude ionospheric F2-layer and sporadic E-layer over Hungary, revealing significant dawn-time electron density increases and layer fade-outs unrelated to sporadic E-layer activity.

Contribution

It provides detailed analysis of ionospheric responses to geomagnetic storms at midlatitudes during solar cycle 24, highlighting the timing and nature of electron density changes.

Findings

Significant electron density increase at dawn during storms

Ionospheric layer fade-out occurs independently of sporadic E-layers

Different storm phases show distinct ionospheric behaviors

Abstract

In our study we analyze and compare the response and behavior of the ionospheric F2 and of the sporadic E-layer during three strong (i.e., Dst <-100nT) individual geomagnetic storms from years 2012, 2013 and 2015, winter time period. The data was provided by the state-of the art digital ionosonde of the Sz\'echenyi Istv\'an Geophysical Observatory located at midlatitude, Nagycenk, Hungary (IAGA code: NCK, geomagnetic lat.: 46,17{\deg} geomagnetic long.: 98,85{\deg}). The local time of the sudden commencement (SC) was used to characterize the type of the ionospheric storm (after Mendillo and Narvaez, 2010). This way two regular positive phase (RPP) ionospheric storms and one no-positive phase (NPP) storm have been analyzed. In all three cases a significant increase in electron density of the foF2 layer can be observed at dawn/early morning (around 6:00 UT, 07:00 LT). Also we can observe the fade-out of the ionospheric layers at night during the geomagnetically disturbed time periods. Our results suggest that the fade-out effect is not connected to the occurrence of the sporadic E-layers.