EGU21-12569
https://doi.org/10.5194/egusphere-egu21-12569
EGU General Assembly 2021
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Statistical estimates of auroral Pedersen conductance using electric and magnetic measurements by the Swarm spacecraft

Heikki Vanhamäki1, Anita Aikio1, Kirsti Kauristie2, Sebastian Käki2, and David Knudsen3
Heikki Vanhamäki et al.
  • 1Space Physics and Astronomy Research Unit, University of Oulu, Oulu, Finland
  • 2Finnish Meteorological Institute, Helsinki, Finland
  • 3Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada

Height-integrated ionospheric Pedersen and Hall conductances play a major role in ionospheric electrodynamics and Magnetosphere-Ionosphere coupling. Especially the Pedersen conductance is a crucial parameter in estimating ionospheric energy dissipation via Joule heating. Unfortunately, the conductances are rather difficult to measure directly in extended regions, so statistical models and various proxies are often used.

We discuss a method for estimating the Pedersen Conductance from magnetic and electric field data provided by the Swarm satellites. We need to assume that the height-integrated Pedersen current is identical to the curl-free part of the height integrated ionospheric horizontal current density, which is strictly valid only if the conductance gradients are parallel to the electric field. This may not be a valid assumption in individual cases but could be a good approximation in a statistical sense. Further assuming that the cross-track magnetic disturbance measured by Swarm is mostly produced by field-aligned currents and not affected by ionospheric electrojets, we can use the cross-track ion velocity and the magnetic perturbation to directly estimate the height-integrated Pedersen conductance.

We present initial results of a statistical study utilizing 5 years of data from the Swarm-A and Swarm-B spacecraft, and discuss possible applications of the results and limitations of the method.

How to cite: Vanhamäki, H., Aikio, A., Kauristie, K., Käki, S., and Knudsen, D.: Statistical estimates of auroral Pedersen conductance using electric and magnetic measurements by the Swarm spacecraft, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12569, https://doi.org/10.5194/egusphere-egu21-12569, 2021.

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