Turbulent motion generally exhibits highly “irregular” structures and exists in all types of fluids around us. It can for example be observed within rivers, in the neutral atmosphere, and in the ionosphere, the ionized part of our atmosphere. In the ionosphere in particular, irregular structures in density can have negative effects on our technological infrastructure, as they can for instance impact Global Navigation Satellite Systems (GNSS) signals.
Our key scientific motivation is to understand the creation and behavior of ionospheric irregularities in the auroral regions, where they are known to be strongest. To address this challenging topic, we plan to take advantage opportunities related to the new EISCAT_3D, a cutting-edge radar system currently under development in Norway, Sweden, and Finland.
In preparation for the radar observations, we have developed methods to improve the quality of measurements and observations of the ionosphere by radars. We are also currently investigating and developing observation techniques that will be applicable to the new EISCAT_3D system to monitor the ionosphere in 3D, and to resolve how density structures evolve both in space and time. Furthermore, we have performed modelling work to study the creation of ionospheric irregularities associated with flow shears in the high-latitude ionosphere. Next modelling efforts will study the impact of other energy sources. The simulation results also allow us to identify the typical characteristics of the associated turbulence (such as scale-sizes, how the energy is transferred across the scales etc.), as well to validate and constrain measurements. On the observational side, radar measurements are combined with national and international research infrastructures, including high-resolution cameras, GNSS receivers, and data from existing and future sounding rockets such as those from the Grand Challenge Initiative(s) to study the source regions, development, and features of the turbulence. The project consolidates both national and international collaboration, and the results are being published in scientific literature and presented at conferences in Norway and abroad.
Altogether, the novel methods developed combined with multi-instrument observations and modelling work will allow to resolve outstanding questions about the formation and characteristics of ionospheric turbulence in the auroral regions.
Turbulent media exhibit a spatio-temporal randomness, or “irregular” character, and, in the ionosphere, the irregular structures in plasma density with scales shorter than a few kilometers are of particular interest for space weather applications. They can for instance disturb High Frequency (HF) radio communication, and degrade Global Navigation Satellite Systems (GNSS) signals. Our key scientific motivation is understand how these density structures occur and to identify the dominant mechanisms responsible for their creation in the auroral region, where they are known to be strongest.
Our main objective is thus to characterize plasma density structuring in the auroral region. To address this challenging topic, we will take advantage of the new EISCAT_3D, a three-dimensional (3D) phased-array system currently under development capable of volumetric imaging, and of providing 3D vector measurements at unprecedented temporal and spatial resolution. We will develop novel measurement techniques allowing to resolve the spatio-temporal evolution of density structures, and to monitor the meso-scale electromagnetic conditions in the ionosphere. EISCAT_3D observations will be coordinated with national and international research infrastructures, including high-resolution cameras, GNSS receivers, and sounding rockets from the Grand Challenge Initiative mesosphere lower thermosphere (MLT), a large-scale international collaboration dedicated to study the physics and chemistry of the MLT system. Additionally, theoretical work and numerical simulations will be conducted to validate and understand the observations, as well as to predict and constrain the plausible physical mechanisms taking place. Altogether, the novel methods developed combined with multi-instrument multi-scale observations and modelling work will allow to resolve outstanding issues about the spatio-temporal characteristics of turbulence with space weather impacts on technology.
