Angular dependence of wide altitude ion line enhancements (WAILEs) during ionospheric heating at the EISCAT Tromsø Facility

This thesis presents the first sub-radar beam resolution determination of the angular width of wide altitude ion line enhancements (WAILEs), found to be 0.5 degrees around magnetic zenith, observed during a HF radio wave heating experiment at the EISCAT Tromsø Heating facility on 27 November 2014. The results of ray tracing simulations are detailed. The simulations are based on the hypothesis that WAILEs are caused by ducting of UHF radio waves due to artificial field aligned irregularities and the results of the experiment. Ducting of a 930 MHz radio wave was caused by 15.7% depletions from the background density in an IRI model atmosphere with fOF2 = 10.04 MHz. The data analysis and modelling methods used to achieve these results are explained. The fundamentals of HF radio wave interactions in plasma and the theory of incoherent scatter radar are discussed. The thesis concludes with recommendations for further research on WAILEs and field aligned irregularities caused by X-mode heating