Investigation of Ionospheric Plasma Structuring and Processes related to Auroral Particle Precipitation

Abstract

Radio-waves propagating through the ionised part of the atmosphere, the ionosphere, can get impacted by plasma structures and irregularities. The effects on the signal can be observed by ground based receivers, and are indications of plasma structures the disturbed signal encountered. In this thesis, the aim is to understand how energetic particles precipitating into the ionosphere from space are related to plasma structuring and radio wave propagation disturbances. The signature of particle precipitation are auroral emissions. Auroral emissions are observed by all-sky cameras, with filters for different wavelengths. Studying how the aurora moves in space and time and in relation to it, how signal disturbances evolve in space and time, allows to gain understanding of plasma structuring and instabilities in the ionosphere. To classify plasma instabilities in detail, measurements of plasma parameters, such as electron density and temperature, are required. Commonly used instruments to measure them are Langmuir probes. In this thesis, a method was developed using machine learning, to infer electron temperature measurements at the sampling resolution of the instrument. The topics addressed in this thesis are important for future space weather services, and in particular reliability of the satellite based positioning services.