Abstract:
This paper investigated the variation in the F1 and F2 region electron density during a
geomagnetic activity at East Asian mid-latitude stations. In this analysis, D(foF1) and D(foF2)
representing deviation of the critical frequency for the F1 and F2 ionospheric regions respectively
were employed. The F1 region appears to be much more stable than the F2 layer during the
stormy event, as there was no significant effect on the F1 layer in most of the ionospheric stations
under investigation. It was also observed that independent of the sign of the storm effect on
NmF2, the electron density, if any, in the F1 region is always negative. Moreover, no F1
ionospheric response was observed at midnight (0000UT) throughout the storm event in all the
stations; but recorded its maximum effects between 0600UT-1800UT during the day.
Conclusively, there is a considerable intra-hour variability of F2 electron density NmF2 during
ionospheric disturbances.
