The actual state and variability of the Earth’s ionosphere are important aspects of the space weather system. Their understanding is crucial for ionospheric modelling and building the capability of predicting and mitigating severe space weather effects. One example of such effects is the degradation of communication or positioning with the Global Navigation Satellite Systems (GNSS), which is due to ionospheric plasma irregularities impacting the propagation of radio waves. Ionospheric irregularities at various scales are a result of dynamic processes in the ionosphere.
Through the project Swarm Variability of Ionospheric Plasma (Swarm-VIP), as a part of the Swarm+ 4DIonosphere initiative, we provide spatiotemporal characteristics of ionospheric plasma at different geomagnetic latitudes and uncover coupling between various scales in response to geomagnetic conditions. The project employs data from the Swarm satellites, such as the IPIR dataset [1,2], as well as auxiliary datasets. Taking advantage of the orbital characteristics of the Swarm satellites and using complementary scale analysis techniques such as wavelets or Fast Iterative Filtering, we ascertain the dominant scales at given geomagnetic conditions. Our focus is primarily on the characteristics of ionospheric plasma, i.e., plasma density and total electron content as measured respectively by the Langmuir probes and GPS receivers onboard Swarm satellites.
The result of Swarm-VIP is a semi-empiric model for the ionosphere based on the generalized linear modeling. The model determines the probability of occurrence of different scales in ionospheric plasmas with respect to geomagnetic conditions and the magnetosphere-ionosphere coupling. It also gives insight into ionospheric structuring and coupling between scales. The model can be understood in the context of space weather effects, such as scintillations of trans-ionospheric radio signals. The Swarm-VIP model is provided globally, along the whole orbits of the Swarm satellites, and a special emphasis is put on high latitudes, Arctic and Antarctica, and the European sector, where the validation study is carried out with a network of ground-based instruments.
The Swarm VIP project is funded by the European Space Agency’s in the Swarm+ 4DIonosphere framework (Contract No. 4000130562/20/I-DT).
 A. Spicher, L.B.N. Clausen, W.J. Miloch, V. Lofstad, Y. Jin, and J.I. Moen, Interhemispheric study of polar cap patch occurrence based on Swarm in situ data, J. Geophys. Res. Space Physics, 122, (2017), pp. 3837– 3851, doi:10.1002/2016JA023750.
 Y. Jin, C. Xiong, L. B. N. Clausen, A. Spicher, D. Kotova, S. Brask, G. Kervalishvili, C. Stolle, W.J. Miloch, Ionospheric plasma irregularities based on in-situ measurements from the Swarm satellites. J. Geophys. Res. Space Physics, 124, (2020), e2020JA028103. https://doi.org/10.1029/2020JA028103