ICI 4DSpace 2014-2016 : Investigation of Cusp Irregularities by 4D Space measurements

Energy from the solar wind give rise to interference to the radio signal in the polar cap. Satellite-based navigation and communication systems are severely disrupted during powerful solar storms. GPS users with demands on accuracy and reliability want a space weather forecast, which can pre-warn GPS problems. In order to create a space weather YR, it is a prerequisite to describe the underlying physics. According to classical physics, radio wave disturbances occur due to fine-scale structures in the electrically charged gas in the atmosphere - the ionosphere. With the ICI rocket series (Investigation of Cusp Irregularities), we take direct measurements of atmospheric disturbances in the Northern Lights. Through this project, we have developed a new tool to do 3D studies of turbulence in the ionosphere. The 4DSpace module that houses 6 daughter payloads was tested twice during this project. The first time on MaxiDusty 1B in 2016, and the second time on Nammo Raufoss hybrid rocket (Nucleus) test launch from Andøya Space Center in 2018. Both times this failed due to technical issues beyond the responsibility of this project, which meant that we did not get to test the novel experiment technology. We believe that the GPS disturbances are strongest in the altitude range between 300-400 km where the electron density in the F-layer ionosphere peaks. High-resolution in-situ measurements are mandatory to explore the physical processes that generate turbulent structures in the F-layer. We have had special focus on two mechanisms: i) Gradient Drift Instability which operates at the rear edge of moving electron clouds, and ii) Kelvin-Helmholtz Instability which occurs where there are strong wind gusts. In the ionosphere F-layer, there are wind speeds up to several thousand km/h. We have received good estimates of growth rates in the disturbances. With ICI-3, we uncovered a third type of instability. We have used ICI observations as input in a numerical stability analysis for "Energy-Density Driven Instability" (IEDDI), and we have shown that IEDDI can drive "Electrostatic Ion-Cyclotron" (EIC) waves in a wide range of wave numbers and frequencies. IEDDI can thus trigger secondary processes that occur in the flow shears between high-speed flow channels. The IEDDI mechanism can also be a very effective mechanism for heating plasma in the F-layer ionosphere, and possibly help to accelerate oxygen particles in connection with the daylight over Svalbard so that they escape the Earth's gravitational forces (ion outflow). This is a forty-year-old problem where classical theory does not seem to extend. We have carried out statistical studies to map where GPS scintillations are located relative to the Cusp auroras (Daytime Northern Lights over Svalbard). It turns out that the GPS scintillations are mainly co-located with Cusp aurora, which indicates that this region is turbulent. Furthermore, using DMSP satellite data inside the polar cap, we have discovered scintillation regions inside the polar cap, which are associated with plasma clouds (high electron density) and electron precipitation. We have developed a multi-needle Langmuir probe experiment to fly on the Japanese research rocket SS-520-3. During the integration of this instrument in autumn 2017, a technical fault was discovered on the electrical system on board the rocket. The launch opportunity in the winter of 2017/18 as lost. The launch was then first postponed until January 2019. However, due to several projects competing for launch in JAXA, the SS-520-3 mission was further delayed, and now most recently due to Covid-19. A new launch time has not been finally decided, but the first opportunity will be in the winter of 2021/22.

Universitetet i Oslo´s miniatyriserte måleprobesystem (multi-Needle Langmuir probe system» som opprinnelig ble utviklet for raketter, er også godt egnet for satellitter. Teknologien ble overført til Eidsvoll Elektronikk AS som nå har kvalifisert instrumentet for ESA satellitter. Et m-NLP instrument skal leverer til den Internasjonale romstasjonen (ISS). Dette er et resultat av den langsiktige satsningen på den norske ICI-serien forskningsraketter, gjennom flere prosjekter finansiert av Norges Forskningsråd, Norsk Romsenter, og European Space Agency. Intensjonen er fagkunnskapen utviklet innen plasmaturbulens i i Nordlyset er et viktig FoU bidrag til å utvikle «Romvær-YR» som kan varsle problemer med GNSS og radiokommunikasjon i Nordområdene.

Despite that plasma instabilities in the F-region polar cap ionosphere, powered by the solar wind, represents a space weather issue for navigation and communication systems, the underlying physical processes are still poorly understood. Research in this a rea has not progressed as fast as in the equatorial regions, as it is geometrically impossible for high-latitude ground based radar to obtain an appropriate backscatter angle at F-regions using VHF and UHF systems, and the resolution of HF systems is too coarse. Therefore, the only possibility to characterize these small-scales irregularities is by means of in-situ experiments, and sounding rockets represent a strong tool. GNSS users want scintillation forecast models, and the ultimate space weather produ ct will be to provide it. However, we are far from having a proper description of plasma irregularity formation and hence we are equally far from having a scintillation forecast model. The ICI-rocket program strategy is to develop building blocks for phys ically based models. The ICI-series of rockets has so far been focussed on testing specific instability modes and to quantify their growth rates. The next step is to investigate spatio-temporal variations with focus on decay rates. Due to ambiguity proble ms with 1D measurement by single rockets, there is a pressuring need to develop 3D in-situ measurement techniques. This will be materialized by the combination of rocket mother and miniaturized daughter payloads. In order to take advantage of 3D micro-sca le measurements we will develop 3D numerical codes to simulate the performance of rocket and daughters. These numerical tools will be used to optimize mother-daughter configurations, and to analyse the data afterwards. The rocket data will also be used in analysing the associated GNSS scintillations observed on ground during each flight. Because scintillations occur under a variety of physical conditions there is a need for the ICI rocket program to continue.