EGU21-812
https://doi.org/10.5194/egusphere-egu21-812
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Dynamics of ionospheric and telluric currents during large events of geomagnetically induced currents

Mirjam Kellinsalmi, Ari Viljanen, Liisa Juusola, and Sebastian Käki
Mirjam Kellinsalmi et al.
  • Finnish Meteorological Institute, Helsinki, Finland

Geomagnetic variations are mainly produced by external currents in the ionosphere and magnetosphere, and secondarily by induced (internal/telluric) currents in the conducting Earth. Large geomagnetically induced currents (GIC) are associated with large time derivatives of the horizontal magnetic field. Recent results show that the time derivative is typically dominated by the contribution from the telluric currents. Our study aims to find measures to quantify the behaviour of external and internal currents and their time derivatives during large GIC events. Results of this study show that strong external currents have quite narrow directional distributions. Angular variation is larger for internal currents, and especially for their time derivatives. For external currents angular variation is larger at higher latitudes. Similar behaviour is not seen with internal currents.

How to cite: Kellinsalmi, M., Viljanen, A., Juusola, L., and Käki, S.: Dynamics of ionospheric and telluric currents during large events of geomagnetically induced currents, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-812, https://doi.org/10.5194/egusphere-egu21-812, 2021.