Multi-instrumental investigation of the solar flares impact on the ionosphere on 05–06 December 2006

The sudden increase of X-radiation and EUV emission following solar flares causes additional ionization increased absorption electromagnetic (EM) waves in the Earth’s atmosphere. flare impact on ionosphere above Europe 05 06 December 2006 was investigated using ground-based (ionosonde VLF) satellite-based data (Vertical Total Electron Content (VTEC) derived from GNSS observations VLF measurements DEMETER satellite). Based Kp Dst indices, a quiet day, while there geomagnetic storm 2006. total fade-out EM emitted by ionosondes experienced at all stations during an X9 class variation fmin parameter (first echo trace observed ionograms, it is rough measure “non-deviative” absorption) its difference between period have been analyzed. A latitude dependent enhancement (2–9 MHz) Δfmin (relative change about 150%–300%) every station time (on December) M6 flares. Furthermore, we analyzed VTEC changes after events with respect to mean values reference days. During flare, depending (2–3 TECU 5%–20%). On 2006, (5–10 TECU) representing “positive” ionospheric storm. However, peak related could not be detected. We also quantifiable transionospheric signals ground transmitters detected low Earth orbit associated data. Moreover, amplitude phase ground-based, subionospherically propagating were measured simultaneously analyze reaction evaluate electron density profile versus altitude. For calculated parameters (sharpness, reflection height) important for description modelling this medium under forced ionization.