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FRINATEK-Fri prosj.st. mat.,naturv.,tek

LIPS: The Lifetimes of Ionospheric Plasma Structures

Alternative title: Plasmastrukturers levetid i ionosfæren

Awarded: NOK 3.8 mill.

The LIPS project sets out to shed light on how turbulent plasma in the ionosphere disappears. Turbulent plasma dissipation is an important topic for the future, with a direct impact on key space technologies. Indeed, without a proper understanding of how turbulence dissipates in space we cannot safeguard technological assets in space from the dangers caused by it. The ionosphere is Earth’s closest space environment – here, radiation from the Sun is strong enough to ionize a small portion of the atmospheric gases. Through known physical processes, turbulence forms throughout these gases. In some cases, radio signals are diffracted by plasma turbulence, resulting in disruptions in services that rely on GPS or satellite communication. Though the growth of such plasma turbulence has been shown great attention, its decay and subsequent decline has not. LIPS will build on recent research into the subject of turbulence dissipation, and seek to answer a number of unanswered questions: why does the traditional theory of plasma diffusion not match recent observations? Why does dissipation in equatorial and polar regions seemingly operate with different principles? What is the impact of simultaneous growth and decay of turbulent structures? To answer these questions, LIPS will utilize new observations from a state-of-the-art Korean satellite constellation called SNIPE. The SNIPE constellation will orbit in 2022, and consists of four small satellites, each equipped with several scientific instruments. Unique for SNIPE, the satellites will orbit in a tightly controlled formation. Such a tight orbit control has never been performed with low Earth orbit satellites, and will yield detailed information about small-scale plasma properties in the ionosphere, with so called multi-point measurements. The findings to be uncovered by LIPS will form the foundation for a wider plasma turbulence dissipation framework, with applications in real-world industries such as space exploration.

LIPS intends to shed light on plasma structure decay in the upper ionosphere, in both the polar and equatorial regions, by performing direct measurements of structure lifetimes, using a novel set of multi-point plasma measurements. In the ionosphere, plasma structure lifetimes are a result of chemical recombination and plasma diffusion. Whereas the growth of plasma irregularities have been paid considerable attention, their decay have largely not been studied, and plasma structure lifetime has consequently been paid little attention in the scientific literature. However, the topic is important, as every technological problem associated with plasma irregularities (radio scintillations, e.g.) are directly impacted by the lifetimes of those irregularities. LIPS identifies three main challenges in the field of F-region plasma structure lifetime. First, the measured scale-dependency in high-latitude plasma structure lifetime deviates strongly from the theoretical predictions. Second, measurements of equatorial F-region plasma structure lifetimes yield results that are completely scale-independent, suggesting that the mechanisms are not fully understood. Third, small-scale plasma structures result from instabilities, meaning the growth of turbulence can badly offset structure lifetime calculations. LIPS will resolve these issues by use of completely new multi-point plasma measurements performed by the Korean SNIPE satellite mission, which will be launched in 2021. A constellation of four satellites will orbit in tightly controlled formations. Whereas researchers performing power spectral density analyses on conventional satellite data have to contend with treating 3D plasma structure projections to 1 dimension, LIPS will be able to approach plasma structures without this simplification. The methodology we propose has real potential as a tool to scrutinize scale-dependent physical phenomena in ionospheric plasma, paving the way for future scale-dependent investigations.

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FRINATEK-Fri prosj.st. mat.,naturv.,tek