Ionospheric characteristics in response to gradients of magnetic eta index
Abstract
We present the analysis of correlation of typical ionospheric characteristics with the changes of the magnetic eta index. The eta index is defined as the square root of a ratio of the energy of the external part of the vertical component to that of the horizontal components. The values of eta typical ranged between 0 and 0.1 sometimes exceeds 1 or even higher values which means that the changes of the vertical component of magnetic field is larger than the changes of the horizontal magnetic field components. In most cases when eta index indicate some magnetic disturbances other magnetic indices (i.e. Kp, Dst) inform about quiet conditions. During increasing phase of eta index value ionospheric characteristics present large deviations from their monthly median. Our analysis for 2004 present deviations of foE up to +/- 0.9 MHz and both deviations negative and positive appear during enormous increase of eta index. Another ionospheric characteristic, the virtual height of F2 layer (h’F2) decreases in some cases up to 90 km from monthly median value. Here the analysis of correlation between ionospheric characteristics and the eta index will be presented taking into account time interval covering the whole solar cycle for European region.
- Publication:
-
40th COSPAR Scientific Assembly
- Pub Date:
- 2014
- Bibcode:
- 2014cosp...40E.771D