Schmidt Institute of Physics of the Earth, Moscow, Russia
Abstract. Using data of the ionosonde in Sodankyla, (SOD, 67° N, 27° E, Finland), parameters of variations of foF2 critical frequency in the Pc5/Pi3 (1–5 mHz) frequency range are studied. For that, a technique of automatic detection of critical frequency from an ionogram is developed. The variations of foF2 are compared with the Pc5/Pi3 geomagnetic pulsations on the ground and in the magnetosphere. The variations of foF2 are in the majority of cases decoupled from the Pc5/Pi3 on the ground. Meanwhile, the analysis of geomagnetic and foF2 variations at SOD show intervals with noticeable coherence for both horizontal components. These coherent pulsations are predominantly registered in the afternoon MLT sector. Statistically, their spectral content, polarization and spatial distribution differs from those of background variations. Coherent pulsation tend to occur under moderate geomagnetic and auroral activity, SW speed, and dynamic pressure fluctuations. The fraction of coherent geomagnetic and foF2 pulsations is higher for the geomagnetic pulsations registered in the magnetosphere, than on the ground.
How to cite. Yagova, N., Kozlovsky, A., Fedorov, E., and Kozyreva, O.: Geomagnetic pulsations in the Pc5/Pi3 frequency range and fluctuations of foF2 frequency, Ann. Geophys. Discuss. [preprint], https://doi.org/10.5194/angeo-2019-155, 2019.
Received: 10 Nov 2019 – Discussion started: 03 Dec 2019
We present a study of ultra-low-frequency waves in the ionosphere and on the ground (geomagnetic pulsations). They can influence particle flux in the magnetosphere, which modify the ionosphere. However, there is no simple dependence between geomagnetic and ionospheric pulsations. We study not only selected pulsations with very high amplitudes but also usual pulsations and try to answer the question, which pulsations' parameters are favorable for modulation of the ionosphere.
We present a study of ultra-low-frequency waves in the ionosphere and on the ground (geomagnetic...